passivhaus Archives - House Planning Help

HPH293 : What is Passive House Accelerator? – with Zack Semke

November 18, 2020 by Lucy Cowell Leave a Comment

Zack Semke explains why he's passionate about facilitating the communication and flow of information around Passive House.

Interview with Zack Semke

Zack is based in Seattle, where he works in marketing consulting services for the high-performance building industry. He is also a director of Passive House Accelerator: a website that brings together different sources of information to educate, inform, and promote the work that is being done by the Passive House community.

The construction industry has lacked innovation

Compared to other industries, construction has been famously lacking in innovation, but Zack says that Passive House is changing that. By using physics to understand how to design and construct buildings better, Passive House is re-thinking the basics of the skeleton and skin to improve performance.

The learning from new technologies will drive down costs

Zack uses the example of solar energy to show how there has been a massive drop in the cost in recent years.

He attributes this to Wright's Law and the learning curve effect, which applies to all technologies. It says that for every doubling of units produced, there will be incremental reductions in the costs. This is brought about by the additional learning and micro-innovations that happen across the supply chain. In the case of solar energy, Zack says it looks as though every doubling of solar panels across the world brings about a fall in prices of 30%.

The same principles can be applied to Passive House buildings, so that costs can be driven down to more of a cost parity with conventional construction.

There has also been progress in the components supply chain over recent years, with triple glazed windows for example coming down in price.

And once costs become on a par, it becomes a no-brainer to build Passive House, with all the lower energy and health benefits too.

“That’s why I’m so passionate about facilitating communication and flow of information between practitioners, policymakers, marketers and whoever it is, because we want to accelerate this process as much as we can so that when a project happens in the UK and there are lessons learned from that project, we can see that learning being applied in Seattle for example.”

We know what we're getting with Passive House!

Zack credits the focus on physics as providing such an important contribution to the sustainability movement. The development of tools like PHPP, which are not too complex or too simplistic to use, mean that there won't be the performance gap that can be found with other green building standards.

There will be a wave of uptake

Zack is encouraged by the explosion of Passive House that is happening across parts of North America, particularly in Vancouver where enlightened public policy is incentivising Passive House and net zero construction, and New York City where carbon emission restrictions on existing buildings are being imposed, paving the way for huge numbers of deep energy retrofits.

And whereas the Living Building Challenge has been incentivised, it was designed to be exactly what it says – a challenge. Zack says that it doesn't factor in scalability and is seen as the moon-shot of green building. Passive House on the other hand is set up to be cost optimised.

“As cities become actually serious about delivering on climate goals, they’ll recognise that there is no other green building standard or approach that rivals Passive House on reducing operational carbon emissions.”

He gives the example of affordable multi-family buildings in Pennsylvania. The body that oversees the funding, the Pennsylvania Housing Finance Agency, has prioritised Passive House in their scoring for projects that are looking for funding. It doesn't cost the state anything to add that as a priority, and the result is that developers know if they include Passive House in their schemes they will be at greater chance of securing funding against competitors. This has seen a wave of Passive House construction of affordable housing in the state.

Pax Futura Passive House apartment building in Seattle. An example of the kind of urban infill, multi-family Passive House building that we will need to see more of in order to address the climate crisis.
Image Copyright Cascade Built

Embodied carbon is a challenge we have to address

“Operational carbon is the first thing that we need to tackle in my view, but just like so many things in the climate action space, it’s not an either/or conversation.”

Zack credits the Living Building Challenge for the new zero carbon certification, which is one of the first to consider how to reduce and offset embodied carbon.

He says the Passive House community is embracing embodied carbon as a challenge, and the Passivhaus Institute is dedicating resources to its research and thinking about tools for how it could be addressed. He would be keen to see them including energy-related embodied carbon calculations and looking at the implications of those decisions.

The Passive House Accelerator shares information and innovation

Created just over a year ago, the Passive House Accelerator is an open source global platform, that is partly a place that shares content that others have created about Passive House. They also host virtual weekly presentations by Passive House experts, followed by Q&A sessions on screen.

In addition, they present a podcast, and host roundtable discussions, on a variety of related topics.

Find out more

Visit the website of Passive House Accelerator

Follow Zack on Twitter

Transcript

Download a transcript of the interview with Zack Semke.

Climate Champions Podcast

Hattie Hartman, Sustainability Editor at the Architects' Journal, has launched a new podcast with architect George Morgan from One Point Five Architecture.

It aims to share knowledge in an era of climate emergency, speaking to change-makers and innovators who are transforming architecture as we know it by designing in ways that respect planetary boundaries

Find out more.

Please connect with me

Subscribe, rate and review the podcast in iTunes

Rate and review the podcast on Stitcher

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HPH288 : Renovating a 1960s house for comfort and efficiency – with Russel Hayden

September 9, 2020 by Lucy Cowell Leave a Comment

Architect Russel Hayden explains how he sought to renovate a derelict 1960s house to EnerPHit standards.

Interview with Russel Hayden

Russel is an architect who, up until four years ago, had spent his whole working life in London. Prompted by a desire to leave London and move closer to family, he and his wife bought a derelict house in Stockport with the intention of it being a project to renovate, before selling it on and moving out of suburbia.

They bought the house through a sealed bid system

At the time, Russel and his family were renting out their house in London and lodging with his in-laws in Stockport when the house opposite came on the market. It had been left in a state of abandonment for around ten years after the owner had died and heirs were being sought.

The house went to sealed bids, and they won it with a bid of 5-10% over the asking price.

The budget was set by what they thought the house would be worth when complete

At around the same time they left London, they received an inheritance which enabled them to buy the house in Stockport, with enough left to cover the renovation works. Despite a few little extravagances, they mostly kept things simple, and having the budget set gave them a clear direction and target. They did end up spending a little more than they expected to, but felt they got good value.

Upon completion, they had the house valued at significantly more than they had expected. And despite thinking this project would be a stepping stone to something else, they love the house and the area, and have no intentions of moving.

Time pressures meant there was no fixed price with the builder

As they hadn't finished all the drawings, they recruited a local builder to get the house stripped back while they were still living in London. Once they moved, Russel was able to take on the project management role, finish the drawings and oversee the procurement of materials.

Having that experience and understanding now, he does acknowledge a new found respect for builders for the work they put into getting the materials, finding the right price and coordinating their delivery.

The builder embraced the learning involved

The builder had been recommended to them, and although he had never done a project like this before, he had a good attitude and a genuine interest in learning about Passivhaus. That's not to say there weren't also times where he found it frustrating not being able to carry on with his work in the usual way.

Russel paid him and his team of two helpers a daily rate, which isn't something he would necessarily recommend a self-builder do, but he was living opposite with his in-laws and could be on-site every day to keep a close eye on things.

Passivhaus consultants were employed

Russel had done the Certified Passivhaus Designer course before leaving London, so understood the principles involved, but knew that he didn't have the experience to tackle it on his own.

They engaged Enhabit to help with the Passivhaus consultancy, who set out four options of how far they could take it: getting it to Building Regulations standard, to AECB Silver, to EnerPHit, and to Passivhaus standard.

With Russel effectively wanting to use it as his business card for his new venture in the north, they felt it was important to do something that was certifiable and within a reasonable cost. Settling on EnerPHit basically then set their brief.

“On reflection, it was a very helpful device actually because it then made everything very clear about what we had to do. I think that’s one of the beauties of Passivhaus. Although there are infinite ways of achieving it, you do have a very real target.”

The building was wrapped externally with insulation

The house needed a new roof, so making the decision to go with that and wrapping the brickwork in external wall insulation, gave them a clear steer of how they were going to develop the project.

They sought planning permission because the 280mm insulation would increase the house footprint by around half a meter, and with an extra foot of height on the roof ridge line.

One of the biggest challenges was with the concrete slab floor, and the problem of the cold bridge at the perimeter. Without wanting to spend huge amounts of money on it, they decided to accept there would be a cold bridge there, but put insulation on the retained slab. They mitigated that by dropping 150mm of insulation externally down to the foundation level.

They kept structural changes to a minimum

By deciding not to move windows and doors around unless absolutely necessary they were able to keep the costs down. They did need to remove a chimney breast though, as it wouldn't have worked with Passivhaus.

Adding the floor insulation meant the floor was raised to the level of the first step on their stairs. On the first floor they removed the ceiling plasterboard to expose the joists and give a sense of a bit more height.

One of the big changes they made was reducing the size of the garage and extending onto the back of it to make a space that is used as a garden room, office, and exercise studio. It has a timber frame construction with a straightforward flat roof, making it a cost-effective addition to the project.

Russel's wife Anna is also an architect and she spent a lot of time researching materials for the interior finishes, and finding fittings which weren't necessarily particularly expensive.

They chose a parquet flooring for the ground floor and a lighter oak parquet for the upstairs, which together with the full height doors in the rebuilt partitions, gives continuity between the spaces.

They fell just short of their airtightness target

One of the biggest challenges on the project was getting the connection to the existing house right, and particularly minimising the thermal bridges where the garage and extension connect.

Russel thinks the workmanship around that connection was responsible for them just failing to achieve their airtightness target, with a result of just over 1.1 (where 1.0 is required for EnerPHit). By the time they had that final airtest they were past the point of being able to go back and remedy where the problem may have been. This did mean that frustratingly they weren't able to get the certification they were hoping for.

The hands-on experience has been invaluable professionally

Among the things Russel learnt from this project, was about having the right and patient approach with people. This was particularly the case with having employed a builder on a daily rate rather than a contract.

He also found that being so involved on site and doing the taping himself, meant that he was gaining a much better understanding of things that worked and things that didn't, which invariably will influence the way he goes back and details buildings.

“I think what’s been brilliant about the Passivhaus Designer Course is that I’ve realised that for the last thirty-odd years I’ve been detailing and designing buildings not terribly well without a proper understanding of moisture and how buildings work, thermal bridges and things like that.”

He is now working on a Passivhaus self build

They have since bought a 1960s concrete panel bungalow in the Lake District which was won through another sealed bidding process. With the bungalow quality not living up to that of the view, it became quickly apparent that their best option would be to demolish and replace it with a new building. It is currently at the planning stage and they are looking to make it a timber frame construction built to Passivhaus, or ideally Passivhaus Plus, standards. Being in a World Heritage Site they are keeping their fingers crossed!

Know your limitations and keep things simple

For anyone thinking of carrying out their own retrofit, Russel says the budget will be key but it can be very difficult to know how far you can go within that. The balance between getting to the level of comfort required without spending a huge amount of money can be a challenge.

It is easier if a particular standard is the target, but without that you are left with a number of options.

It is best therefore to understand the difference between what you want to spend and what you need to spend. Spend it carefully and you'll get what you pay for. By keeping it simple it will be easier to design and build, and you'll get a lot more for your money.

Find out more

Visit the website of HESKETHHAYDEN

Follow Russel on Twitter

Transcript

Download a transcript of the interview with Russel Hayden.

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HPH287 : A beginner’s guide to retrofit – with Russell Smith

August 26, 2020 by Lucy Cowell Leave a Comment

Russell Smith of Parity Projects explains why a whole house plan is the best way forward for tackling a renovation.

Interview with Russell Smith

Russell is a chartered civil engineer whose interest in renovation began after a secondment with the charity Forum for the Future. He began to understand the gravity of climate change and learn about the impact of energy and carbon emissions attributed to the housing stock. This led him to tackle his own housing renovation project, around 16 years ago, at a time when most of the talk was about new builds.

The renovation of his Victorian property managed to get his heating bills down to around £50 per year. He opened his house up to around 3,000 visitors during the three years he worked on it and was honest with them about what he had discovered, how hard it was and how much it cost.

Russell realised there was a business opportunity in it and started his own company, Parity Projects.

A ‘whole house retrofit' is something of a misnomer

Russell describes retrofit as being the bits and pieces that are retrospectively fitted. A whole house retrofit is actually a deep refurbishment where everything is done at once.

“Provided you’ve got a game plan right at the start knowing how everything should fit together in the long-term then your retrofits should add up to a whole house refurbishment in the long-term.”

Too much information can scare off new customers

Providing full and detailed calculations and drawings at the outset is likely to overwhelm the majority of people, as they wouldn't be aware that quite so much was needed.

Instead, Russell starts by using just enough data to help a customer understand the size of the problem and the opportunity of what is possible with the house. By displaying what the priorities are, they can agree on an appropriate package of measures before moving to the next phase. This would involve much deeper analysis and calculations for every element of the building.

Phasing a renovation over time takes extra consideration

Russell explains it can be particularly difficult to get all the elements to fit together if they're not carried out together in one plan.

“If you’re only installing some of the measures or you’re only tackling some of the things that you would want to do upfront, really you want to make sure that those things don’t have to be undone to do the next things later on.”

So ideally it makes the most sense to carry it out in one go if possible. It's the least costly way of doing it, materials can be bought in bulk, it can all be carried out while no one is living there, it doesn't have to be tidied away completely at the end of each day, and the airtightness layer and ventilation can be considered for the whole building rather than just room by room.

Russell does acknowledge that this won't always be possible as people might not have somewhere else to stay or the finances available all at once.

Ultimately we want to reduce our demand for heat

The first step therefore is looking at where heat is being lost. Using the example of a three-bedroom semi-detached property, he explains the different areas:

Solid walls

The biggest proportion of heat loss will be through the walls, and without a cavity the insulation will need to either go on the outside or the inside of the building. Careful consideration needs to be given into the way the building was designed to behave, and whether there is already moisture in the brickwork that needs to dry out before any work can start. External wall insulation can be relatively straightforward provided it's designed properly.

Windows and doors

This involves heat loss both through the windows and doors themselves, as well as infiltration around the outsides where they have been installed. If they're not going to be replaced then the gaps around the structures need to be dealt with very well.

Under-floor

Russell says typically around 15% of the heat loss can be through the floor so it's important to address it early on.

Roof

The roof makes up a large part of the surface area of the house and there are plenty of elements which make each unique, such as the different type, orientation, and rainfall.

Ventilation

Once the building has been made more airtight and insulated, you need to ensure a good level of ventilation so that the air quality for the occupants is of a high standard.

“Once you’ve got all of those things dealt with in combination, you’ve resulted in a much lower energy demand than you would have done in the first place. And that’s the point to start considering your heating system and how you would put some heat into the building.”

The Passivhaus standard deals with these elements

It is important to ensure that you are ventilating and insulating in combination to get to such low levels of heat demand where a heating system can be virtually unnecessary. But while that's an aim for every property, the restrictions of budget, priorities and logistics will mean that not every building will be able to reach that.

There needs to be government backing

Russell believes there needs to be a government campaign to make people understand the potential of their property and where it can get to provided that strong decisions for a whole house plan are made.

“It’s got to happen. We’ve got no choice. That is going to happen so that when they are planning their shiny new kitchen, the new bedroom or they’re just redecorating, they can incorporate those things into their thinking.”

There also need to be low-interest finance options to enable people to move forward.

Quality depends on good communication

Quality starts with the design, putting the right list of things together and communicating it properly to the contractor.

“I think people tend to bash contractors in the first instance for poor quality but the bottom line is, if the contractor’s not been told what to do very well then it’s never going to work.”

Something Russell has been working on for the last seven years with a cooperative he set up called RetrofitWorks, is bringing those disparate parts of the industry together as part of one organisation. The aim is to give everyone tools at their disposal to do the design, communicate with each other and implement the work so that they can all check anything at every step of the way.

Cosy Homes Oxfordshire is a manifestation of the key partners they have built up in that area. With some central government funding buying into the model they have been able to define the marketing, clearly describe the approach they think their customers want, design their processes as a cooperative, push forward with the advice, the whole house plans, the detailed design and putting a tender process in place so the right contractors are selected and they can make sure their work is done well.

Charlie Luxton visits a deep retrofit in central Oxford

Charlie Luxton visits a refurbishment of a listed barn

Charlie Luxton checks out a retrofit of a semi-detached property

They have also used their established supply chains with the creation of the Warmer Sussex scheme, and Ecofurb which will be launching in London soon.

There aren't enough skilled workers to meet government targets

Parity Projects have used modelling tools to identify that the current workforce of around 160,000 in the sector would need to be virtually tripled in order to achieve the government's target of every house in the UK hitting a minimum EPC score of C by 2030.

Russell sees this time as a massive opportunity to be training people up from other industries for working in managerial roles as well as the labourers. He thinks that all students in the building sector should complete the same one year course before branching out into their specialities. That way there might be more respect and understanding on site.

Select a team that is willing to learn

Russell's advice to a homeowner considering a renovation project would be to contact a local retrofit coordinator. They will be able to give you advice and technical knowledge to put a plan in place for your property.

He stresses that if you're going to do your home up you will probably need to accept that some people working on it might need to learn something new, so ensure that you team up with people that have the right attitude, a genuine interest and are keen to help. Even if they don't necessarily know it, they will learn and find out.

There are also free resources available on the AECB website in their Knowledgebase section, and from the Centre for Sustainable Energy.

Find out more

Visit the website of Parity Projects

Learn more about RetrofitWorks

Follow Russell Smith on Twitter

Check out our previous episodes with Parity Projects, about what to expect from a detailed energy assessment, and how an assessment can inform retrofit measures.

Parity Projects carry out an energy assessment at Ben's parents' house

Transcript

Download a transcript of the interview with Russell Smith.

Please connect with me

Subscribe, rate and review the podcast in iTunes

Rate and review the podcast on Stitcher

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HPH285 : Developing plant-based building materials – with Judith Thornton

July 29, 2020 by Lucy Cowell Leave a Comment

Dr Judith Thornton of Aberystwyth University explores how plant-based materials are being used in the building industry, and why they are so important for our future.

Interview with Judith Thornton

Judith works within the Department of Biological, Environmental and Rural Sciences at Aberystwyth University. She specialises in projects at the interface of plant science and material function, with her main interest being the use of plants as building materials.

It's about more than just building with straw or hempcrete

Judith says that, historically, because of the finely honed skills required for each approach, there has been a tendency for the natural building industry to divide off into those that build with straw, and those that build with hempcrete. There are of course many other plant types that can be used, depending on the design criteria.

She explains that we shouldn't assume that we could build the whole project out of plants either, and nor should we assume that only one plant type will be suitable for each of the different building elements.

Judith uses walls as an example, where because they provide the dual functions of structure and insulation, it might make sense to separate those elements out and use different materials. She says that otherwise, wherever you're trying to get a particular product to perform multiple functions, you may well end up with significant compromises.

Do your research

Even within strawbale building there are different types of straw that can be used, but Judith says people rarely demand a particular variety, and generally just accept what they're given.

“I have yet to meet a strawbale builder who knew what wheat variety was in their building!”

Historically the tendency is to use wheat straw, within which there are also a number of varieties, but sometimes barley straw is used. Barley straw however is far more prone to rotting than wheat straw, which Judith says should be a bit of a red flag when thinking about building with it.

In Wales they have tested out building with miscanthus straw, which is a grass that can grow to three metres high, so is much tougher than wheat or barley, and presumably should be more resistant to breaking down.

Judith says that there tends to be an assumption that strawbale buildings are inherently low energy, but that's not necessarily the case. If they're not built properly they can be leaky and rot, not very airtight and have high energy bills in the same way that any other building can.

There is a lack of aspirational standards

“We’ve got a regulatory system where we’ve got a fairly ineffectual stick and absolutely no carrot. So, ‘this will comply with building regs’, and people will say that as if that’s a good thing. Well, complying with building regs is as bad as you’re allowed to be before you get prosecuted. That isn’t an aspiration, is it?”

Judith believes that there is a lack of incentive to build to the Passivhaus standard using low impact materials. She sees it is a combination of lacking aspirational standards and not valuing building enough as a trade, when it's actually a very skilled profession and a challenging undertaking to build to Passivhaus standards.

One of the key challenges with Passivhaus is getting the airtightness, and particularly concentrating on the junctions between different materials. It can be as problematic for man-made materials as it is with plant-based materials though. Particular care needs to be taken when designing details at junctions between timber and straw for example, where you might get some shrinkage in the plaster when it's butted up against a timber frame.

There would be no sense in trying to build an entirely plant-based building

Judith thinks it would be ludicrous to even try. Using airtightness tapes as an example, she explains it as the law of diminishing returns: where a small amount of a very high tech materials provides a massive benefit. She says there is no point in obsessing about whether your strawbales are tied with polypropylene string or whether your airtightness membrane has got formaldehyde glue in it.

“Partly because it makes almost no difference to the total carbon in the building and partly because it’s based on this completely false premise that natural things are safe and manmade things are dangerous. That simply isn’t true. But it’s a very commonly held environmental world view.
“We do this weird moral balancing in the UK where we say, ‘I’ll fly abroad on holiday, but I did do my plastic recycling’. The whole plastic debate for me is seeking to shift blame to manufacturers as an alternative to examining our own behaviours.
“It’s not rocket science. As individuals, we need to eat virtually no meat, we need to stop flying on holiday, and we need to insulate our houses.”

Establish what the building industry needs

Judith thinks that academics can have a tendency to come up with solutions for problems that don't necessarily exist. So part of her role is having conversations with the building industry and the plant scientists to work out the areas that need new materials, and how the plant science community can contribute.

One example is of insulating solid wall houses in Wales and doing that with vapour permeable materials. She says that hemp lime or another material mixed with lime is an excellent way of achieving internal wall insulation whilst minimising risks of interstitial condensation. It then becomes a question of analysing what it is that the plant material is doing in that mixture, seeing whether other plant materials are available, and then carrying out testing.

Prevent biodegradable building materials from biodegrading!

There are significant differences between various plant materials in how easily they biodegrade, and this will impact on the longevity of a building. The key thing is to stop moisture from getting in.

Plants contain variable amounts of silicon and lignin in their cell walls which are protective against being broken down by microorganisms. Even different wheat straw varieties will contain different levels of lignin, which would impact on how quickly an individual piece of straw would rot if it were exposed to moisture.

So one of the initial decisions to make when planning your build is as to how you plan to deal with moisture, and whether for example you have a vapour-permeable construction where moisture can diffuse into and out of the wall, or whether it will be a completely sealed envelope that relies on mechanical or window opening systems for moisture management.

We will need to move to a plant-based economy

Before fossil fuels we had a plant-based economy, and going forward this is something that we will need to revert to once again.

Judith is involved in the university's BEACON project, which looks at plants as products and how biorefining can help us move to a natural feedstock-based economy.

“Everything we use on a day-to-day basis, be it building materials or plastics or everyday items, is going to need to be made out of plants and it’s a question of how we best do that.”

Online Learning Resources

Check out these sites for online resources, including webinars and training:

Find out more

Learn more about the work of BEACON

Read Judith's Blog

Transcript

Download a transcript of the interview with Judith Thornton.

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Subscribe, rate and review the podcast in iTunes

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HPH283 : Modelling the embodied carbon of your build – with Tim Martel

March 25, 2020 by Lucy Cowell Leave a Comment

Tim Martel explains how to model the embodied carbon of your build using PHribbon, a tool that plugs in to PHPP (Passive House Planning Package).

Interview with Tim Martel

Tim is a qualified architectural technologist and Passivhaus designer. He also works for the AECB and is a course tutor for the CarbonLite retrofit course. Helped by a background in programming he has used his research and experience of working on new builds and retrofits to create PHribbon – a tool which enables people to model the embodied carbon on their build.

PHribbon is designed to specifically work with the PHPP software

While there are other specialists who do work on embodied carbon, PHribbon is unique in that it has been designed to work specifically with the Passivhaus Planning Package (PHPP). This is a benefit because around 80% of the information needed is already in PHPP. The additional information needed will be the things that aren't covered by PHPP, such as internal walls, floors and roof coverings.

The calculation is built around a RICS document

The Royal Institute of Chartered Surveyors (RICS) wrote a document in 2017 called ‘Whole Life Carbon Assessment for the Built Environment.' It's a statement of what members have to adhere to and sets out in detail what is expected of the calculation. While the RICS calculation can only be done once a building is complete, Tim is able to use quantities that are in PHPP to give a good estimate of what the embodied CO₂ of the building is likely to be.

Information is gathered from Environmental Product Declarations

CO₂ results can be shown in different ways

As long as you are able to provide the net internal area (NIA), results can be shown as kilograms of CO₂ per metre squared of net internal area. In addition the graph can be customised to show total CO₂ for the whole building, kilograms of CO₂ per metre squared of TFA (that's usable space in Passivhaus language), and even CO₂ per occupant.

Awareness is drawn to potential inaccuracies

Tim stresses this isn't an official calculation, but it does closely follow the RICS standard. There will however be some inaccuracies, and these are highlighted by a colour coded system in PHribbon to draw attention. Some EPDs they can be fairly certain about so will be coloured green, but others that they're less confident of will be orange or red. They might be ones that are based on RICS assumptions like 300km being the assumed transport distance from various manufacturers to the site if its a national product, whereas in reality it's likely to be more or less than that.

Generally speaking, the information is likely to get more accurate as more EPDs are produced, and with more available it's highlighting just where the missing information is. In particular, it would be useful to show information for the end of life stage, and include reuse and recycling benefits.

Results can be tailored to show alternatives

With several examples already completed, Tim says his findings show a typical semi-detached house as having around 14 tonnes of CO₂ for the whole life of the building, with about 10 tonnes of that just for the materials themselves. The benefit of using PHribbon is that comparisons can be made in a graph by using different options, such as what the figure might be if the house was made out of brick, as opposed to timber.

Example of whole building using timber, PIR versus brick

Example showing 100m2 wall using timber, cellulose versus brick

More information is needed about the end of life stage

With some of the more typical timber constructions where I-beams and cellulose are used, both of those have quite a large storage component so a large bar represents that storage which offsets all of the emissions in the RICS calculation.

Tim says there's a catch with this though, as one of the assumptions is that in order to include storage you have to do a full life calculation. That then uses the RICS assumption that 75% of the timber is incinerated at the end of life stage, with the other 25% going to landfill. Unfortunately there isn't currently enough information about recycling and reuse to produce those in the EPDs as an alternative.

“If you could say, ‘this building has been built so that it can be taken apart and recycled. This material is ideal for being recycled so it can be made into OSB, MDF or anything’, if that can be done and we can prove the figures for it with an EPD for that process then you could legitimately add that as another option.”

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HPH282 : How to share knowledge, test and debunk! – with Nick Grant

March 18, 2020 by Lucy Cowell Leave a Comment

Nick Grant shares his thoughts on the lessons learned from 30 years of the AECB (Association of Environment Conscious Building).

Interview with Nick Grant

Nick Grant from Elemental Solutions is a Passivhaus consultant and also Technical Director of the Passivhaus Trust. He's been on the podcast a couple of times before talking about value engineering and integrated design.

Nick has had a long involvement with the AECB (Association of Environment Conscious Building) and at the conference last year, celebrating 30 years of the AECB, Nick and Alan Clarke gave a presentation about lessons that have been learned during that time, and Ben was keen to explore this further.

The AECB has an openness of critical thought

Nick highlights that the AECB has a strong ethos of accepting when you're wrong, realising mistakes that are made and learning from each other's mistakes. That's not to say it's an easy thing to do, particularly when you've spent years becoming an expert in something and then admitting that's perhaps not the best way of doing it.

“So, some of these things, it’s better to know than not know because you could carry on for the rest of your life to your grave doing things that turn out to not be worthwhile.”

Becoming aware of all the negatives and then getting rid of them, leaves you with the bits you want, which turns it into a positive.

Passivhaus works!

Nick explains that when he built his own house, he'd heard of Passivhaus bu there wasn't enough information in English to know much more, other than it was about thermal bridges and airtightness. His own house was designed intuitively without any energy modelling, because with the walls over a foot thick and a foot thickness of loft insulation, there didn't seem much point. It was only later when they modelled it that they realised it wasn't great, primarily because of the form factor.

Sheila makes the engineered DIY rafters (to save a bit of cash)

The term ‘thermal bridges' wasn't in the Building Regs, and while they knew what it meant, they didn't realise that around a third of the heat could be escaping through them if they weren't dealt with. It's only now, having done the analysis on hundreds of buildings, that they have a learnt intuition.

Nick attended the first Passivhaus conference, back in 2007, partly to debunk it, and partly out of curiosity. But having been to the talks and seeing some of the buildings, he realised that it actually worked and was very impressed with what he saw.

Whereas before there would be arguments about thermal mass and all sorts of discussions that were points of opinion, now Passivhaus is a simple model that can be used to give the answers.

It's important to use critical thinking and questioning

This is something that Nick says the AECB has been particularly good at, and should be a fundamental part of learning.

Not everyone does this however. Particularly among some designers there can be a resistance to it, because of not wanting to have constraints that will mean their visual design won't work.

He would rather embodied carbon be kept separate from the Passivhaus Standard

In the early days of the AECB, Nick says where there tended to be more emphasis on using natural materials, then the performance aspect had to be abandoned and the building justified in other ways, such as lower embodied energy.

Nick says this doesn't have to be the case and just because you might be talking about one aspect, it doesn't mean the others have to be ignored.

“I think the problem is when you pursue one and it causes a problem for the others or it excludes the others. So, if the energy performance requires things that are ugly or polluting or something like that, then that’s a problem. But that’s not what I’d want to do. So, it’s a compromise.”

In terms of whether Passivhaus should go down the route of incorporating more about embodied carbon, Nick doesn't believe that it necessarily should. He would rather it be kept separate from the standard, otherwise there can potentially end up being trade-offs that happen in other green building standards, like where there's lower embodied energy there can sometimes be higher operational use.

The problem with embodied energy is complex

There are conflicting views, with a good example being timber.

“Depending on how you do the accounting, some people see timber as a negative thing and that leads to the idea that the more you put in the building, because you’re locking up carbon, even to the point where the building is not emitting carbon until ten years into the future when the operational has overtaken the embodied.
We think that’s nonsense. Most of our buildings do use timber but we don’t see that as negative. It’s still every time you cut down a tree and turn it into a building, carbon is emitted. I’m not an expert but I’m assuming there’s less emitted than if we use steel or masonry and so on. That’s why we like to use timber. But we don’t see it as negative.”

A timber frame construction using i-beams

Off-setting alone isn't enough

When it comes to off-setting, Nick says there aren't enough trees that can be planted to do all the things that we need for building, flying, running vehicles, heating homes, making electricity etc.

“We’ve got to do off-setting in the sense that we’ve got to plant loads of trees and we’ve got to do all that stuff. But we can’t do that instead. We can’t say, ‘I’ll fly to America and plant a tree and that’s fine.’ We’ve got to do the not flying to America and the planting of trees and the not using energy. There’s not enough off-setting possible.”

Existing building stock is a problem

Nick says that most of his work is new buildings, partly because it frustrates him that the new buildings of today are being done so badly and are the retrofits of the future. But a bigger challenge is what should be done with all the existing building stock, and this is something that he doesn't have the answer to.

One thought is to retrofit them all to Passivhaus standard, but that seems incredibly difficult, particularly with listed buildings. In some cases where they're in a state of disrepair, adding in extra insulation or triple glazed windows is a no-brainer, but a lot of retrofit isn't like that. Many are perfectly good buildings that are going to cost nearly as much to retrofit as a new building would cost.

Designing buildings for the future gives a false sense of security

Nick says that designing buildings that can adapt to higher temperatures or flooding in the future can be a dangerous thing as it gives a false sense of security that we can survive this. We need to be designing for the hot summers and extreme weather that we get now.

With so much change happening so quickly, such as a rise in fascism and better awareness of climate issues, Nick says it's hard to predict even one year ahead.

“But that’s what keeps us going I suppose, thinking that at least we’re doing the right thing. On one level, incredibly pessimistic; absolutely can’t see any way this is going to end well. But at the same time, what else do you do?”

The AECB has had a big impact

Nick explains that although the AECB is a small organisation, it has had a big impact, with most of the best performing buildings having had AECB members involved.

In contrast, he says things like the World Green Building Council seemed to be made up just of people who had paid to have membership, with no Passivhaus buildings, and none that the AECB would consider to be exemplary.

“Within our little group, it feels like things are moving forward. But if you step out of the bubble then it feels like it’s unknown what we’re doing.”

Image credit Lancaster Co Housing and Eco-Arc

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HPH281 : What’s it like to be an owner builder? – with Tully Gallagher

March 11, 2020 by Lucy Cowell Leave a Comment

Tully Gallagher of Beartooth Passive House, explains what it was like to take a leap of faith in swapping a desk job with building a ‘forever home' for his family.

Interview with Tully Gallagher

Tully had been working as an engineer in Denver for ten years when he and his family decided to move back home to Montana.

“We went from having a very stable income, stable benefits, a pretty consistent life, to moving back home, not having jobs, living in rental houses.”

With intentions to return and build their “forever home” for his family that would be a healthy and comfortable place to live, Tully had originally selected a builder to achieve their high performance house. When that fell through in 2017, and with the chance of finding an alternative that had even heard of Passivhaus, let alone built one, being fairly unlikely, it seemed the natural decision to take on the project themselves.

Tully took on the house building project full-time while his wife found work at the local school to keep an income coming in.

Passivhaus Builders' Training gave him confidence and connections

With his construction experience amounting to limited remodels of previous accommodation, Tully took the Passivhaus Builders' Training in 2017. With that came access to highly knowledgeable people that he could lean on for tips and feedback during the planning phase.

Keeping it simple was crucial

From the outset when they decided to build the house themselves, they opted to keep the form very simple: a two-storey rectangle with engineered roof trusses.

Emu Systems, who delivered the Passivhaus training, were trying to standardise construction methods for different climate zones and were looking for partners to pilot their system. It was a good fit with what Tully was looking for so they worked together on the construction system, building science, wall details, window installs etc.

The remote location brought its own challenges

Located about four miles from the town of Red Lodge (population of around 2,000), their site was relatively flat at the top of a hill in a sparsely populated area. One of the biggest problems about the location was the absence of any major DIY store; the closest being an hour and a quarter away.

The location for the house was based on a transformer being a couple of hundred feet away so they could connect electricity without a problem.

For waste water they had a septic system installed, and for incoming water they hired a company to drill a well. A pump runs from the well and is connected to a line that runs into the house, with a pressure tank supplying the pressure to the house and holding a reserve of the water.

They used a pre-determined build system

Partnering with Emu meant the construction system was already determined, which was a Passivhaus double stud wall system. Overall wall thickness is around 20 inches, incorporating mineral wool batt insulation, interior finishing and exterior siding.

With the house being a basic rectangle shape the airtightness strategy didn't pose any problems. The only junction that took more consideration was at the second storey floor system and how to get the air barrier out and around the floor joists.

“But it was definitely something that we thought of early on and we picked the materials that we used for that air barrier specifically because they were really easy to work with and they were really strong and robust. They could stand up to if somebody accidentally bumped into them or something accidentally hit it and ripped it. It was pretty easy to repair and get it back to air-sealed.”

They have moved in while finishing the interior

Tully and his family moved into their home during November 2019. It isn't yet finished but the pace of work has only slowed a little now that they're in and are working on finishing the interiors. Interior doors are due to arrive soon, then it will be finishing the window trim and putting a lime plaster on all the interior walls. The bathroom installation is currently underway which Tully sees as a fairly big undertaking because of its size and his lack of experience.

Make time to have a break

A particularly difficult part of the build was the roof, which he saw as his nemesis and was one of the times he wished he was back at his desk job! Although not afraid of heights, he doesn't particularly love them and with the ridge of the house being around 30 feet off the ground even getting the sheathing up there was difficult.

He remembers one specific heart-sinking day where they had stapled all the underlayment down when it started getting very windy. Looking up from where he was having lunch at his parent's house nearby he could see it starting to billow in the wind before a big length of it gave way and started flapping about. They ended up putting a metal roof on the house, with Tully admitting that the first couple of panels while they were figuring it out weren't the prettiest and were put at the back of the house where they wouldn't be seen!

The biggest challenge Tully faced was knowing when to walk away and take a break.

“I was wanting to get things built and it got to the point where coming out every day, I started to become a little bit more easily agitated and I just needed a break. That’s something that was a struggle for me all the way through building, knowing that I want to continue making progress so that we can move in, but at the same time I needed to take a break so that mentally and physically I could recover.”

Take your time in the planning stages

Tully says that although it's been hard and taken a long time, if they hadn't first gone through such a detailed design and planning stage it would have been a lot more difficult.

“So, from a design phase and early implementation phase, that’s the time where it doesn’t cost you really much more money to take another month or two months to really get things lined out and understood. So, that was a big learning experience for me.”

From a teaching perspective going forward, he would like to specialise in high performance building envelopes and the installation of that system, including the air barrier, insulation and windows. He would also like to explore the possibility of doing that in a pre-fabricated manner where the walls, floors and roof can be made into panels that can be trucked to the site and installed within a matter of days.

It's been a stressful but satisfying experience

Tully's advice to anyone taking on something similar, is to be prepared for it to take a very long time, especially if you're doing it yourself. Spend time planning and thinking everything through as it's a lot better to make the mistake during the planning stage than when you're actually building it.

Tully spent a lot of time doing 3D modelling in SketchUp, using it to model every single framing member before cutting any timber at all. He found it helped him to think through all the different junctions and how it would all work together.

He also says to be prepared for it to cost a lot more than you are expecting.

“So, if a budget constraint comes up and you have to choose between having really nice counter tops or spending the money to put in an additional X amount of insulation and focus on airtightness, I would say really consider that airtightness and insulation piece because you’ll probably never do that again or never have the opportunity to do that again. But you can save up for a year and upgrade your kitchen counter tops really easily.”

“It’s stressful. I’d like to say that I’ve had way more stress in the last year-and-a-half than I had in the previous eight years probably combined. But I think I’ve also lived more and experienced more in the last year-and-a-half both in emotion and physical, actual achievement, than I had in previous years.
I’d had an office job for the most part. I did a little bit of fieldwork. But when you go in and you’re on a computer, you can build some really cool spreadsheets or do some cool stuff in software but it’s not the same thing as being able to go to work, work hard all day, then leave and look at a forty foot long, nine foot tall wall that you built and stood up that day.”

Find out more

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HPH280 : A beginner’s guide to the Passivhaus Standard – with Jon Bootland

March 4, 2020 by Lucy Cowell Leave a Comment

Chief Executive of the Passivhaus Trust, Jon Bootland, explains the processes and benefits of building your house to the Passivhaus Standard.

Interview with Jon Bootland

When Jon Bootland finished his university degree he began his employment first as a building services designer, and later working on good practice for sustainable low energy buildings, now with nearly 30 years experience. He has also been involved with the Passivhaus Trust since it was formed back in 2010. With initially very slow progress since the first Passivhaus was completed in the UK in 2010, numbers are now increasing rapidly at around 1,200 completed buildings (of which around 200 are individual owner-occupied homes), with another thousand already in the pipeline.

Carrowbreck Meadow – Image copyright Jefferson Smith

There's nothing hugely complicated about Passivhaus

The origins of Passivhaus come from Germany, where the physicist Wolfgang Feist wanted to find a way of making sure that high performance buildings actually delivered on their claims, and performed the way that they were designed to do.

“It’s all about building physics. There’s nothing hugely complicated about it. It’s just what do we need to do to actually make it work and do what we said it was going to do.”

High in comfort levels, low in energy use

The fundamentals of a Passivhaus are:

Insulation – This is an important part of reducing the energy required to heat the building. A typical Passivhaus might have up to 30cm of insulation, meaning that the walls will be very thick.

The building fabric and airtightness – The other parts of the building will also need to have a very high performance. Windows for example will need to be triple glazed with good quality frames and careful detailing about how they fix together. The airtightness of the building is important with the aim being to stop draughts coming in and heat leaking out.

Ventilation – Because the building is now free of draughts, attention then needs to be paid to how to ventilate it. A mechanical ventilation system is used (MVHR) to bring fresh air into the building, while recovering the heat from the outgoing air.

As well as dealing with keeping the house warm in winter, Passivhaus formulae also look at the sun and other heat sources coming into the building and how the ventilation and insulation can work to keep it cool in the summer.

Old Holloway – Image copyright Juraj Mikurcik

Have a Passivhaus expert in your team

Jon says that building a Passivhaus is harder to do than a normal house, but that doesn't necessarily mean you have to employ a team of specialists. He would however recommend having someone in your team that does have Passivhaus training, and preferably experience. It doesn't have to be the builder, but could be the architect or a consultant.

The Passivhaus Planning Package does the calculations

You will need someone who knows what they're doing to fill in the Passivhaus Planning Package (PHPP) and work out the answers to the calculations with you. It is a tool that takes a holistic approach to making all the elements work together, to make sure you end up with a building that has the performance and comfort that you are looking for.

There are benefits to having certification

PHPP should be used right from the beginning to look at the size and shape of the building, the window locations, balconies or anything else that might penetrate into the building etc. A certifier is able to check what is being put forward and advise on whether what you're suggesting is actually going to work in the way it is intended.

Without having a certifier on board you will not be able to call it a certified Passivhaus, which does have some value in being able to sell the project. Certification is the best way of ensuring that your building will meet the required standards and provide the comfort and energy performance that you are looking for. If you're not planning to use a certifier, then Jon recommends ensuring your team of architect, builder and consultants have plenty of Passivhaus experience between them to give you confidence it will perform as intended.

There are health and cost benefits

Jon outlines some of the key benefits of a Passivhaus:

Lower energy bills – The extra insulation and airtightness means less heat is escaping from the house, and therefore less energy is needed to heat it. Typical heating bills for a standard sized Passivhaus might be around £100, compared to several hundred for a non-Passivhaus equivalent.

Health benefits – Jon says there are research projects planned in the next few years looking into this, but there is still plenty of anecdotal evidence from occupants talking about the health benefits of living in a Passivhaus. As well as thermal comfort, the air that comes in can filter out air pollution and pollen, and people have reported improvements in asthma conditions. The mechanical ventilation also reduces moisture levels in the building which prevents condensation and mould.

Some construction methods will be harder than others

Jon says that although you could achieve Passivhaus with any construction type, it will be harder to achieve with brick and block for example than with timber panels. Although it's possible to do, it will just need to be approached differently.

The extra outlay is money well spent

Jon uses social housing to get comparable benchmarks for how much more a Passivhaus will cost to build over a standard form of construction. Typically the additional cost of building a Passivhaus will be around 4-8% higher. Jon says that probably half of that is just on better quality building, which actually should be applied to all new buildings anyway, regardless of whether they're Passivhaus.

So on a £200,000 – £400,000 build cost, that's likely to add on just £8,000 – £16,000 extra.

“So, say you’re going to get a much better quality building that will make you more comfortable, more healthy and will perform better for 50, 100 years or more, it’s a very small amount of money in my book and it’s a much better way to spend your money than on a super flashy designer kitchen.”

There are ways to keep costs down

The shape and form of your building is crucial in keeping the costs down. Adding on multiple wings, outlying parts, differing floor levels, balconies additional roofs, lots of corners and odd shapes, will all make it more difficult to make a Passivhaus work, and will be more costly.

Jon wouldn't recommend everyone try and build a square box as being the answer, but the closer you aim to a square box shape the easier it is to achieve Passivhaus.

Another way to keep costs down is to bring in your Passivhaus expert as early as possible. Don't wait for the design to be finished and then call them in to do the calculations, but involve them at the design stages to help develop the building shape, window sizes and locations etc.

Multiple heating sources are not needed!

Jon explains that it can be challenging mentally to think of a house not needing multiple heat sources in it, but really they're not needed.

Commonly though, people might put a radiator by the front door so that as you walk in there is a perception of extra warmth, while your body adjusts from the cold outside to the comfortable 20-21 degrees inside. A heated towel rail in a bathroom is also quite popular.

The design needs to minimise overheating risk

With homes becoming more energy efficient, the risk of overheating in the summer is becoming more significant and has to be planned for.

The main source of heat coming into the house in the summer will be from the sun, mostly in the late afternoon and evening. To stop the heat coming in without losing the views, Passivhaus buildings will often have some kind of shading or overhang on the west or south facing walls which keeps out the heat until later in the evening when the temperature drops.

There are also other heat sources to take into account such as the occupants and appliances, which heat the house slowly during the day. This data also feeds into PHPP to calculate how much heat will need to be taken out of the building to keep it cool. This can be done using the mechanical ventilation, or by opening the windows, particularly overnight. The temperature fluctuation in a Passivhaus will only be a few degrees, compared to 10-15 degrees in other houses.

“But the extra insulation and the extra performance of the windows, the doors and so on helps in the summer. Just as much as it helps in winter in keeping the heat in, in the summer it keeps the hot air out.”

The Passivhaus Trust oversees the standard in the UK

The standard was invented and developed in Germany, but in the UK it is looked after by the Passivhaus Trust. Their job is to look at how to apply and make the Passivhaus work in the UK, with our differing weather patterns and culture. Jon gives an example of these different considerations being parts of Scotland, where people don't want to open their windows for night-time cooling because of midges coming in, so different approaches have to be developed.

The second aspect to their work is promote the adoption of the standard, by engaging with central government, local authorities and trying to get people on board.

Jon accepts that while it's a great standard it's not perfect, so the third part of their work is carrying out research on specific aspects that can be changed and improved over time.

There are different levels of Passivhaus standard

There are two main standards: Passivhaus Classic for new build and EnerPHit for refurbishment. The criteria for achieving EnerPHit are slightly less stringent because it is that much trickier to do a retrofit. Certain aspects of the building are fixed and can't be changed, so an allowance is made that if you can't change those things you can still get Passivhaus.

The Barrel Store – an EnerPHit Standard youth hostel. Image copyright Mac McClure

In addition there are also two new standards: Passivhaus Plus and Passivhaus Premium, which are effectively the Passivhaus Classic but with renewables. Passivhaus Plus is where the energy generated by the renewables will exceed the energy demand of the house and reach zero carbon. So the energy generated will be equal to or more than your energy used during the year.

Passivhaus Premium takes that a step further with enough renewables to create an energy positive house, so you're generating more than you need and reclaiming money back from the grid.

PHPP can be used to calculate embodied energy

Within the planning tool they are now looking at add-ons which consider the embodied energy of the materials that you use and form part of the Passivhaus calculations. This will benefit people who are keen to use natural materials or who are just interested in understanding how much embodied energy there is. Jon stresses it is not a requirement for achieving the standard, it's just developing the capacity to do it for those that would like it.

Find out more

Visit the Passivhaus Trust website, and learn more about their Passivhaus goes Personal campaign

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HPH279 : A beginner’s guide to building terminology – with Lee Fordham from Architype

February 26, 2020 by Lucy Cowell Leave a Comment

Lee Fordham from Architype simplifies some of the terminology you might come across if you're thinking about doing a sustainable self build.

Interview with Lee Fordham

Shortly after qualifying as an architect in 2004, Lee spent time travelling and working for architecture practices in New Zealand and Australia. When he returned to the UK he decided to pursue his passion for sustainable design and started working at Architype, one of the UK's leading sustainable architects, where he is now an Associate Director.

A beginner's guide to terminology

For those that are just setting out in their self build journey there can be an overwhelming array of technical terminology used that can be baffling to anyone outside of the industry. Lee takes us through some of the common terms that you might come across in a sustainable self build.

Passivhaus / Passive House

Passivhaus (Passive House in the United States) is a building standard that was developed in Germany around 30 years ago. Using physics, the aim is to reduce the performance gap between how the building is designed to perform, and how it actually performs.

The aim is to make the building more comfortable for the occupants and reduce how much energy the building uses, which is done with a better quality of build.

Liz and Mike Hill's Passivhaus – designed by Architype

The experts will use the Passivhaus Planning Package (which you'll hear referred to as PHPP), which essentially is a very complicated spreadsheet of data that allows them to design a building that will meet the Passivhaus criteria. The contractor will use that information to construct the building, and a certifier will guarantee the work and certify it if it meets the required standard.

MVHR

You'll commonly hear a Mechanical Ventilation Heat Recovery system referred to as an MVHR. They're most likely to be used in Passivhaus buildings, but not exclusively. It is a ventilation system which extracts the used air from inside a building. It takes the heat from that air and mixes it with fresh air which is being brought into the building from outside, to provide every room with fresh, pre-warmed air.

The air is filtered coming into the building, and different filters can be used according to whatever is in the external air in that area.

A key benefit over natural ventilation is the element of control over any given space, ie removing moisture from bathrooms etc.

An MVHR for a domestic dwelling is roughly the size of a combi-boiler and will need to be incorporated into the building's design.

MVHR unit at Landsdowne Drive Passivhaus – Green Building Store

Foundations / Footings

These will usually be designed by a structural engineer and are what sit under the building to evenly transfer the weight of the building to the earth. The type you use might be dependent on what your ground conditions are like, but some examples are pile foundations, deep strip foundations and raft foundations.

U-value

A complicated one to explain, but essentially it's a way of measuring how thermally conductive a component or a series of components (like a piece of glass, wall or roof) is. It is the rate at which heat travels through. The lower the U-value, the better it is.

The aim is to have fairly consistent U-values across all the components in a building. Having just one element that isn't consistent could act as a magnet for moisture and potentially damage the structure. This can partly be achieved by better insulation, triple-glazed windows etc.

The U-values form part of the data that feeds into the PHPP system.

Airtightness

At a very basic level, this is about eliminating drafts in a building. It's relatively easy to achieve but needs to be thought about at the design stage. At Architype they denote the airtightness layer on their detailed drawings using a red line, which shows the contractors where to take particular care in the construction so as not to damage it.

To meet building regulations, when the building is finished an air test will be carried out. The building has a giant fan attached to it and is either positively pressured, ie blowing air in, or negatively pressured, ie extracting air. The rate at which the air leaks gives you your air test result. It is a measure in pascals of the pressure of an internal area. Building regs require you to get a result of 10 or less.

The method in a Passivhaus building is slightly different. This takes an average reading from the building being both positively and negatively pressured, to give an n50 value which is how many volumes of air changes there are in an hour. The Passivhaus requirement is that it should be less than 0.6, so significantly better than building regulations.

Build system / construction method

This is a way of describing what method you are going to use to construct your building. Examples include timber frame, masonry, brick and block, insulated concrete formwork (ICF), pre-cast concrete, in-situ concrete, and cross-laminated timber.

Pre-fabrication

Pre-fabrication is where components, or indeed whole buildings, are made off-site. This could be from wall panels, to timber frames, to bathrooms that are fully plumbed and tiled, to entire houses.

You can even go to the factories and choose your handles, paint finishes, floor finishes etc. When they reach the site they are connected together. The advantages of building the elements off-site is it can be quicker, they're not subject to delays or damage from the weather, and often it can result in better quality and working better when brought to site.

Zero carbon

Lee says that this is a difficult one to explain as there are many different interpretations of what it means.

Generally it refers to off-setting the energy use in a building. So the better your building is, ie a Passivhaus, the less carbon you have to off-set because you're not using as much energy.

Looking deeper into it, some people will be referring to zero carbon in use, which is the energy that is used starting from the point of when it's been built, through to its end of life.

But there's also embodied or sequestered carbon, which takes into account everything to do with the design and construction of the building, together with the in-use energy and sometimes through to the demolition. This is more complicated to account for, although there are tools which can help explain for instance, how much energy is used in getting a tree from Germany to the UK to use in a timber frame.

Custom build

Whereas self build has many decisions for you to make, whether or not you're doing it in the purest sense of building it yourself, or whether you're commissioning someone to carry that out for you, custom build can take some of those decisions away from you. There will be an offering from the custom build company, but with options for you to customise it. That could be in terms of the style of the house, the layout or the finishes. It might not be as individual as you would get with a self build, but it can take away a lot of the headaches!

Solar shading / brise soleil

Effectively the same thing, brise soleil or solar shading would be used on the south facing side of a building to limit the sun coming in during the summer months when you don't want the building to overheat, but allowing it to come in during the winter when the heat is required. Generally it would be a horizontal component that sits over the south facing glazing, whether that be a roof overhang, external canopy or series of louvres.

External louvres – Charlie Luxton Design

Wimbish Passivhaus Scheme – Parsons & Whittley

Ditchingham Passivhaus Scheme – Parsons & Whittley

On an east or west elevation you would usually have a vertical component, and that's just to do with the angle of the sun at certain times of day and certain times of year. Windows on the east and west elevation can be harder for dealing with glare and overheating issues.

Lee says the ideal situation is to have the building facing south where the solar gains can be controlled more easily.

Design team

The core members of a design team are likely to include: an architect, structural engineer, civil engineer, mechanical and electrical (M&E) engineer, and possibly a project manager.

Beyond that, depending on your site and your level of involvement and interests, you might also have: landscape architect, ecologist, arboriculturist, quantity surveyor, Passivhaus designer etc.

Renewables

Renewables refers to technology that generates energy. This could be photovoltaics, wind turbines, hydro power etc.

Air source and ground source heat pumps

An air source heat pump takes energy from the temperature in the air. Any air above zero degrees has energy in it and this can be taken and transferred into heat or hot water for your house. Similar in size to a washing machine, they're put on the outside of a building.

The ground source heat pump works in much the same way but will take the energy from the ground. They have pipes which can either be spread horizontally in the ground which will require a lot of space, or as a vertical spread of pipes, which need less space but are a lot more expensive.

Plans, elevations, sections and details

These are examples of the different types of design drawings, created by Parsons and Whittley for Ben Adam-Smith's house:

Plan – This is an aerial view, looking down onto the building. You can have different plans to show each floor of the building, but they can show the roof, doors, walls and windows, together with the internal layout.

Elevation – An elevation is a drawing of what the outsides of the building look like from where you're standing. A south elevation for example would be the side of the building that is facing towards the south.

Section – This is like slicing down through a building to show what's inside. It will show the components of the walls, floors, roof etc.

Details – By taking a section drawing and zooming in you will create a detail. They can be various scales, such as 1:2 or 1:10, and are an in-depth analysis and instruction for the contractor showing how to construct that part of the building. It would show them where the airtightness line is, where the insulation is, and how wide cavities would need to be.

Soft landings and performance monitoring

A soft landing is about making sure that once the building has been constructed, that the operator of that building knows how to use it. Obviously if you've built it yourself then this wouldn't be necessary, but if you've largely commissioned other people to complete the project then you should have someone tell you how it all works.

Performance monitoring can take place throughout the build process but in particular Lee refers to monitoring once the building is complete. This uses sensors to check on things like the internal temperature, humidity and CO₂ levels, to make sure the building is performing as it was designed to do.

Tender

The way you tender will depend on what kind of contract you will have, but essentially a tender is a set of information that is put out to someone for a response. They will price up the aspects on the tender and return it with their figure and requested documentation. It can be a tender for a design team or for a contractor. The returned tender documents are then scored and weighted according to whatever your priorities might be. For some that might be 80% of the marks will be based on how competitive the price is, but for others they might weight it more heavily in favour of quality and not necessarily who is the cheapest.

A key thing is to make sure the information and drawings you are sending out are as comprehensive as possible. That way it can be priced accurately for what you will be needing. Without that detail they will be adding an element of price risk to their response which will invariably make it much more expensive.

Window parts

Sill – The ledge at the bottom of the frame.
Head – The top of a window where it meets the wall. It can be internal or external.
Jamb – The side of the window
Reveal – The part next to the jamb. Can be internal (usually plasterboard) or external (usually timber or brick). If the reveals are set very deep into the thickness of a wall they can provide some shading to the window
Mullions and transoms – Found on traditional Victorian style windows, the mullions are the vertical bar in the middle of the window, and the transoms are the horizontal bar.

Roof parts

Trusses – The pieces, usually made of wood, that actually make the roof structure
Joists – A horizontal structural element that supports the floor and/or ceiling
Eaves – The part of the roof that overhangs the wall. Usually if it's a sloping roof it would be the part which overhangs the gutter
Soffits – Underneath the eaves, the soffits are the horizontal section that you can see
Ridge – The point right at the top of the roof, usually where two pitches come together
Verge – The part at the side of the house. Usually there would be a bargeboard or piece of wood that goes down the side
Parapet – Usually a piece of wall that protrudes up above a flat roof

Find out more

Visit the website of Architype

Follow Architype on Twitter

Transcript

Download a transcript of the interview with Lee Fordham.

The Hub

If you're new to self build and looking for more information, then be sure to check out The Hub. It's full of great resources, video diaries and support from a community of like-minded self-builders.

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HPH278 : A beginner’s guide to self build – with Geoff Stow

February 19, 2020 by Lucy Cowell Leave a Comment

Having worked on his own hands-on group self build project, and site managed others, Geoff Stow shares his experience on where to start when it comes to self build.

Interview with Geoff Stow

Geoff's involvement with self build started years ago when he worked with a community arts project in south London, making a video with a group of self builders who were promoting their scheme in Lewisham. So when Lewisham decided to do another scheme he put his name down, chairing and being part of a group of 13 that built their own houses on a Walter Segal project. From there, his involvement continued with working as a site manager for other group self build schemes, including the Hedgehog project in Brighton.

“My background isn’t as a builder really but I think in some ways that’s quite interesting because it’s actually coming at it as a novice. I’m sympathetic with people who are trying to get a scheme off the ground.”

Geoff also runs courses on timber frame self build, and self build project management at the Centre for Alternative Technology in Wales.

It's likely to be harder than you're expecting!

Geoff says he's never met anyone who said they wished they hadn't done it, but does stress that you should be prepared for a lot of hard work. He thinks there is actually very little in place to make things easier, with the majority of things at the beginning like planning and finding out how to connect services, being geared up to failing.

Whereas most people spend their time at the beginning sketching designs for a plot they don't yet have, he recommends instead taking that time to research and understand the issues involved. That could be around planning, environmental issues, insulation, ventilation etc.

Take the opportunity to go to the exhibitions to grow your understanding and help you talk the same language as the experts, but bear in mind that a lot of it is sales focused.

Understand the issues around claiming back the VAT, and get yourself organised with a good accounting system so you can keep track of staying within budget.

Build your knowledge by checking out some of the self-build books around, like Mark Brinkley's Homebuilder's Bible. They're worth reading for finding out about things like health and safety requirements, working out how you're going to organise your project, whether you might be able to site manage it yourself, and understanding what the relevant issues around that might be.

Use your suppliers by asking for detailed information, and if they can't provide it then don't use them. Geoff gives the example of a window supplier, where you should be providing wall designs and asking what's the best way of fitting them.

Have a sensible budget

Keep in mind that things rarely come in under budget or ahead of schedule, so have a sensible budget that is based on real costings, not just how much you'd like to spend or how much other people have spent. Be wary of the figures that people quote when they say their house cost X amount per square metre, as you never quite know what has been included and what has been omitted.

Budget high for all of the initial stages. Things like the foundations, services and access roads can have plenty of unknowns and it's much easier to price up more accurately for the above ground works. Add on a good contingency once you get quotes in as this should free up money later on.

In addition to budgeting for the overall cost of the build, if you're using a self build mortgage you will need to consider your cash flow. They work by releasing money once a stage is finished, so although you might have enough money in total, you might find the project grinding to a halt if you do not have it available at the right times.

Finding land will probably mean making compromises

Geoff's key piece of advice for finding land is to be flexible, as there's not that much of it around. He thinks it best to spend time in the area where you're looking as quite often word of mouth can be helpful.

Take the time to understand your site

Geoff estimates that, depending on your skill base and level of organisation, around a year is a good length of time to spend on your research. As part of this he recommends spending time on your site and understanding how to place the house so you can get the best out of it. This will include things like orientation, window placement and learning how the sun falls on the site at different times. During this period you can also be going to exhibitions and talks, doing courses, going on Passivhaus open days and speaking to other people that have built their own homes.

Focus on getting the fabric of the building right

Geoff says you're never likely to hear someone say that they wish they'd put in cheaper windows or used less insulation! So concentrate on getting the insulation, windows, detailing of doors, heating systems etc right, and getting it to the best quality that you can afford. It doesn't necessarily have to be the perfect house straight away, and you can always retrofit your dream kitchen or build a second stage later when finances allow.

Speak to other people for advice

Get as much information as you can from suppliers and manufacturers about their products and their detailing. Also speak to builders' merchants who might be able to suggest alternative products that you might not have come across.

Geoff follows a couple of Facebook groups which he says, if you filter through a lot of the rubbish and sales pitches, can actually have really good information and experience that people are willing to share.

“There's no right way of doing it…what there are is a lot of wrong ways!”

Geoff stresses that there is no right build system to use, and the method that you choose will be based on a lot of criteria. Whatever method you do choose, just make sure that it's of the highest quality you can afford.

A lot of it will be down to personal preference, and whether you like timber, stone, brick etc.

Geoff's preference is for timber frame, partly for the accuracy and speed which it affords. He personally would also avoid very innovative systems by very small companies as there can be a question of whether or not they can actually deliver.

Also consider what kind of products you want to be using. Some people might want high performance foam insulation, whereas others will want to go as natural as possible and use sheep's wool or Warmcel type insulation.

“Whatever building method you go with, you just need to really understand what the issues and the criteria are. The good points and the bad points. And ignore what people say about their method being the best, it’s modern or it’s developed by NASA or something ridiculous. Just understand what the issues are with all of them and base it on real costs.”

Decide how much involvement you're going to have

As a client there are options as to how involved you will be on the project, ranging from paying huge sums of money to a building company who will do everything for you, to getting hands-on and doing practically everything yourself.

Probably the biggest deciding factor is thinking about what skills you have, but not necessarily assuming that because you can do something yourself it will necessarily be quicker or cheaper.

“So, if a job that a skilled person can do quickly and well and you can do fairly well and take a long time over, that might mean that it’s longer before you move in and you’ve got more mortgage repayments, more insurance, if you’re renting a house then there’s the rent that you’re paying while you’re doing it. So, you might think you’re saving some money but actually, are you really?”

You might also find that by doing a job yourself and taking longer about it, you might be holding up the next trade that can't come in and do their job until you've finished. Instead there might be jobs that you can do which won't involve holding anyone else up, like prepping and putting up cladding for example.

When it comes to managing the project, you have the choice of paying someone else to do it, or doing it yourself. Obviously doing it yourself in theory should save you money, if done well, but consider whether you have the expertise to: keep things on track and on budget, get prices and employ subcontractors, nudge people when needed, make sure the work is being done to a high standard, check health and safety standards are being adhered to, keep neighbours on side etc.

Do it on the terms of what you can afford, what skills you have and what you want your level of involvement to be.

Being too fixated can be a common pitfall

Geoff sees people that might become completely fixated on building a straw house for example, when actually the site they have might not actually be ideally suited.

“It’s just understanding the issues around those sorts of things and not necessarily getting very fixated on one thing where you end up making your build really complicated because you’ve got this one fixed idea that you saw somewhere on television that you want.”

He also says that no matter what you do there will be people saying that you shouldn't have done it that way. And maybe even you yourself will look back and think you might have done it differently, but just try to get as much right as you can based on the knowledge and research at the time.

People always say they want to be in by Christmas!

Geoff suggests when it comes to how long a project will take, that if you're planning to do a lot of the work yourself then try and avoid it going over two winters, as the second is always particularly tough (especially so if you're living in a caravan!) Realistically you could be looking at 12 to 18 months on site, but less than that if you have builders.

He also recommends trying to get as much finished as possible before moving in, even if that means throwing money at some good contractors to speed things up. Finishing off works once you're living there is much harder to do and becomes less likely to ever get done.

To help keep on track with the budget and schedule, try not to make changes as you go along. You can make minor changes but you don't want to be deciding to change window placement or move walls once work is on site.

Work with an architect who is on your wavelength

Keep a scrapbook of ideas and images that you like and can show to a designer or architect, and make sure you work with someone who is going to design the sort of thing you want.

Although it's not necessary to employ an architect, having a good one on board that is sympathetic to your ideas can elevate your plans and give you a wow factor, rather than simply being a series of rooms joined by a corridor.

Having an architect involved could just be paying someone for a simple check over your plans and offering advice, to a full package of designing the house, getting it through planning and building control, and seeing the whole project through to completion and sign-off at the end.

A key consideration in choosing who to work with is finding someone who is on your wavelength that you feel you can work with. Ask for proof that they really understand the issues that matter to you, as some might claim to be providing a sustainable and energy efficient building just because it complies with current building regulations.

Find out more

Visit the website of the Centre for Alternative Technology

Join House Planning Help's Facebook group

Transcript

Download a transcript of the interview with Geoff Stow.

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Subscribe, rate and review the podcast in iTunes

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HPH293 : What is Passive House Accelerator? – with Zack Semke

Interview with Zack Semke

The construction industry has lacked innovation

The learning from new technologies will drive down costs

We know what we're getting with Passive House!

There will be a wave of uptake

Embodied carbon is a challenge we have to address

The Passive House Accelerator shares information and innovation

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Transcript

Climate Champions Podcast

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Interview with Russel Hayden

They bought the house through a sealed bid system

The budget was set by what they thought the house would be worth when complete

Time pressures meant there was no fixed price with the builder

The builder embraced the learning involved

Passivhaus consultants were employed

The building was wrapped externally with insulation

They kept structural changes to a minimum

They fell just short of their airtightness target

The hands-on experience has been invaluable professionally

He is now working on a Passivhaus self build

Know your limitations and keep things simple

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Transcript

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Interview with Russell Smith

A ‘whole house retrofit' is something of a misnomer

Too much information can scare off new customers

Phasing a renovation over time takes extra consideration

Ultimately we want to reduce our demand for heat

The Passivhaus standard deals with these elements

There needs to be government backing

Quality depends on good communication

There aren't enough skilled workers to meet government targets

Select a team that is willing to learn

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Transcript

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Interview with Judith Thornton

It's about more than just building with straw or hempcrete

Do your research

There is a lack of aspirational standards

There would be no sense in trying to build an entirely plant-based building

Establish what the building industry needs

Prevent biodegradable building materials from biodegrading!

We will need to move to a plant-based economy

Online Learning Resources

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Transcript

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Interview with Tim Martel

PHribbon is designed to specifically work with the PHPP software

The calculation is built around a RICS document

Information is gathered from Environmental Product Declarations

CO2 results can be shown in different ways

Awareness is drawn to potential inaccuracies

Results can be tailored to show alternatives

More information is needed about the end of life stage

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Interview with Nick Grant

The AECB has an openness of critical thought

Passivhaus works!

It's important to use critical thinking and questioning

He would rather embodied carbon be kept separate from the Passivhaus Standard

The problem with embodied energy is complex

Off-setting alone isn't enough

Existing building stock is a problem

Designing buildings for the future gives a false sense of security

The AECB has had a big impact

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Transcript

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Interview with Tully Gallagher

Passivhaus Builders' Training gave him confidence and connections

Keeping it simple was crucial

The remote location brought its own challenges

They used a pre-determined build system

CO₂ results can be shown in different ways