Tag: triple glazing

HPH265 : Preserving the beauty of a building while renovating to EnerPHit standard – with Jonathan Kearns

Jonathan Kearns of Kearns Mancini Architects, describes how he tackled a high performance retrofit of a century-old building.

Interview with Jonathan Kearns

Originally from Dublin and a keen environmentalist, Jonathan emigrated to Toronto in 1975. He became an architect and by 2008 was looking to incorporate his interest in sustainability into his designs. This led him to take the Passivhaus training, with his first project using this methodology being the Reach Guesthouse renovation.

Reach Guesthouse

Reach Guesthouse before renovation

Reach Guesthouse was an experimental exercise

Located two hours east of Toronto in Prince Edward County, Jonathan took on a late 1800s post and beam farmhouse. At around 1700 square feet it had a ground floor with smaller upper floor.

“And so, that project became my learning tool and sort of an experimental exercise in how to renovate an older building and draw all the best qualities out of it while at the same time enabling it to be superbly energy efficient.”

Renovations tend to be more tricky than new builds

Jonathan explains that the Passivhaus training that was developed for new buildings hadn’t entirely prepared him for the task. It took a period of stripping away and demolishing the worst parts of the house to establish whether it would even be worth renovating, but the more raw structure that they uncovered, the more they realised that they could end up with something very interesting and unique.

A friend of Jonathan’s was an artist who in his free periods would also do some construction work. He moved to the site to carry out the selective demolition, using his artistic eye and considered approach to decide what would be worth keeping. This approach did mean the time schedule became stretched, but Jonathan considers it to have been time well spent.

The house was enveloped in Structurally Insulated Panel cladding

Jonathan worked with a local contractor specialising in Passivhaus home projects, who built modular pre-fabricated components in his shop in the local town.

Using 12 inches of SIPs cladding as an insulated jacket to the building, they were able to create a house form very similar to the original. Jonathan describes it as being somewhat surreal to cross from the entirely white exterior through to the contrasting original woodwork inside.

Later additions to the original farmhouse had been poorly built, so they chose to demolish them but use the same foundation to construct a kitchen / dining space on the back of the house.

“So, again, even within the house, you have a very nice contrast of the intimate, richly wooded finishes of the original house, and then you go through into the kitchen dining room and it’s a one-and-a-half storey high open cathedral ceilinged space that is painted white on the inside and is white on the outside and has larger windows that overlook the garden.”

Excluding the basement from the Passivhaus envelope was a painstaking process

With the basement being shallow and built of local stone, Jonathan says there wasn’t much opportunity to incorporate it into the house, so lots of insulation had to be added to the underside of the floor to achieve an air seal.

As they wanted to keep the beautiful, original wooden floorboards, they lifted each one from the ground floor, recorded where they had come from, and preserved and set them aside until later. A layer of Oriented Strand Board (OSB) was laid, taped and sealed, with all the edges being sealed to the outside of the exterior cladding of the original house, so that when the house was wrapped with an air vapour barrier it could be taped to the edge of the floor. The original floorboards were then re-laid.

A particular challenge was the four posts of the house. To complete the air barrier they had to tape three or four inches vertically up each post and down to the floor membrane.

The next project will be a Passivhaus new build

“It makes me want to do new build more than renovation because with renovation, it’s a journey and you don’t know the route. You know what your objective is but you’re starting with something where you can’t see all of the challenges. So, it’s not until you get in and you strip away and you discover all the nuances, that only then can you really make the right decision, make the right design choice.
So, the renovation project really needs you as the architect and designer to be very hands-on and very engaged in the process all the way through. Whereas with a new build, you can really design, think out, calculate and detail every aspect of your new build before you start construction.”

Following Jonathan’s renovation experience, he is now constructing a new Passivhaus guesthouse, called Endymion Guesthouse, which is also in Prince Edward County. Being a completely new build he has been able to site it facing south the way he wanted, and has chosen an ICF construction which could be built by a builder without much Passivhaus experience.

His approach to sustainability has changed

Jonathan says he has always liked the landscape and ecological approach to architecture. He went through periods of being very immersed in looking at photovoltaic panels, wind turbines and the use of geothermal for heating and cooling, but when he studied the Passivhaus methodology he realised they were all secondary to building the primary architectural enclosure to an extremely high performance level.

At the Reach Guesthouse, they have very low energy consumption in summer and winter months for heating and cooling, and the shoulder seasons quite often rely only on keeping the energy inside the building that has been generated by people and appliances.

Something Jonathan enjoys about Passivhaus is he feels it allows him the freedom to work with any material that is appropriate to the design, programme, location and landscape, whilst applying the science as stringently as possible.

Find out more

Visit the website of Kearns Mancini Architects

Follow Kearns Mancini Architects on Twitter

Read Lloyd Alter’s Treehugger article about the Reach Guesthouse

Transcript

Download a transcript of the interview with Jonathan Kearns

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October 6, 2019
HPH263 :A step-by-step EnerPHit retrofit of a mid-terrace home – with Harry Paticas from Arboreal Architecture

Harry Paticas of Arboreal Architecture explains why care and hard work have been so important to the retrofit of his 1978 mid-terrace townhouse.

© Agnese Sanvito

Interview with Harry Paticas

Harry has a background in art and maths, which he then followed with a degree in architecture. He says the turning point in his twelve years in practice as Arboreal Architecture was taking the Passivhaus training course and suddenly being able to understand how buildings perform.

Together with his interest in building performance and the natural world, he also has a passion for retrofit, and is currently getting towards the halfway point of a phased retrofit of his own house, a project which was overall winner at the inaugural ASBP Awards 2019.

“When you put passion in, you get something out”

The house was purchased in 2016 with the aim of doing a retrofit project. Although they had intended on finding something a bit cheaper so they would have more money to spend on the works, this house cost rather more than they had budgeted for which is the reason they are not currently as far along as they had hoped.

It is a south facing, slightly staggered mid-terrace property. It is a combination of a solid brick and block front wall that is tile clad, while the back wall is brick both sides with a cavity.

© Agnese Sanvito

It has been an intensive couple of years working on the house, with every Sunday taken up by long hours of DIY. It has been a massive learning journey which Harry says has also been of benefit professionally.

Not only has the DIY element of the project been hugely rewarding, but it works in parallel with his professional role where he can now speak even more confidently and knowledgeably to clients. This could be about how the MVHR functions, how often you need to change the filters, how the pipes connect etc. Likewise, it aids with speaking to builders and helping them do a better job, which gains more respect from them in turn.

The strategy involves four phases

The first phase involved work being carried out before they moved in. They had sold a property and were renting so that they could get any of the dangerous, dusty and cold work out of the way while living in their rental accommodation. This included asbestos removal from ceilings, airtightness works to the ceiling on the top floor, putting in and taping vapour block boards to each other and to the walls, adding insulation to the loft, making the house secure and weathertight and installing three triple glazed windows.

Generally the plan has been to work from the top of the house down to the bottom. Following the loft works and triple glazing to the front elevation they added insulation to the walls of those rooms. By this time they were living in the house and noticeably felt the thermal shift during the winter weekend when they added the cork insulation to the walls.

A key part of the strategy was maintaining good quality ventilation before the MVHR unit was even installed. With the existing leaky double glazing they knew it wouldn’t be a problem, but when they were replaced with the triple glazing they specified night vents. These allow the handle to be put to 45 degrees off the vertical which gives a 3mm opening in the window at the top. This meant they could maintain decent air quality as an interim measure without the need for installing trickle vents.

By doing lots of monitoring of particulate matter, nitrous oxide, carbon dioxide, temperature and moisture content, they could use the information to decide whether night vents should be open or not.

Harry is currently finishing off bits of airtightness work and interior decorating of phase two before working on the next big phase which will be working out where the living space is going to be. The plans they submitted to the Passivhaus Institute had it on the first floor, but they’re now thinking of having it on the ground floor.

© Agnese Sanvito

According to their EnerPHit retrofit plan, the next phase is to temporarily insulate the garage door. This will instantly reduce heat loss through the whole of the living room floor, the ground floor hallway and a back wall of the garage. In order to do that they will need to block the door and create a new entrance into the garage.

Along with insulating the porch and insulation to the bathroom, these will form phase three, with phase four being the ground floor front and back insulation, and insulation to the floor.

Cork has been used for internal insulation

Harry was always going to use an insulation material that was from renewable sources. He also wanted something that wouldn’t off-gas but be neutral in terms of air quality.

His work with Jane Anderson on embodied and sequestered energy in a range of insulation materials has shown that cork actually has lower embodied energy than wood fibre, and is very good on both counts.

It hasn’t performed as well as hoped in the heat

While internal temperatures have reached 27 degrees, it hasn’t overheated in the Passivhaus terms of over 20 degrees for 10% of the year. With the new windows they are getting 20% less sun through, but with the cork they’re not getting much effect from decrement delay. They have a medium thermal mass and the top floor doesn’t cool down very quickly because of the blockwork walls and brick party walls.

Currently being made are three bright yellow sails which can be attached to the front of the house and shade 100% of the top two windows and over 50% of the large living room window. They will provide a low carbon, low tech solution to shading and reducing overheating, and which can be packed away in a bag in the loft when not needed for the rest of the year. They will also be able to judge their effectiveness scientifically as they have installed sensors on the inside and outside of various rooms of both theirs, and their neighbour’s house for comparison.

It’s also about respecting materials that are already in the building

The process they have adopted has been to try not to replace something if it actually works quite well.

“So there’s a little bit more of a lean towards embodied carbon, rather than very demanding interior design aesthetics.”

This has led to what Harry calls some ‘fun moments’ and to a little bit of variation, which they’re accepting of and saying that’s what this is about, rather than trying to put his architectural stamp on everything and making it as perfect as possible.

It has been an education for his son

With Harry’s son soon turning eight, he was keen for him to be involved and remember the experience as much as possible, with a deep understanding of what it is they were doing and why.

With only a little encouragement at first, his son has been producing a series of A3 posters with images, annotations and diagrams, about cork, airtightness, a thermographic survey, insulation and mechanical ventilation with heat recovery.

© Agnese Sanvito

His teacher engaged with the process and has encouraged him to display them in school and do presentations about them to his class.

A direct result of the school presentations is that Harry is starting a charity or community interest company which will be about retrofitting schools. He will be delivering thermal performance workshops to school children and doing research with them where they look at the fabric of their classrooms and the school and coming up with a retrofit masterplan.

There have been particularly pleasing elements

Having never had them before, Harry particularly loves the triple glazed windows, which is an opinion shared by visitors to the house. They are inward opening with a central flying mullion which allows them to open up a whole elevation and achieve very rapid night time cooling.

© Agnese Sanvito

Another favourite feature is the MVHR unit. They still open windows when they want, but for general air quality which has been backed up with numerical evidence from their monitoring, it has been particularly pleasing.

© Agnese Sanvito

Harry says that working with and getting to know materials has also been lots of fun, particularly with the cork.

Find out more

Visit the website of Arboreal Architecture

Follow Harry Paticas on Twitter

Support Harry’s petition for zero rate VAT on deep retrofit

Transcript

Download a transcript of the interview with Harry Paticas

Please connect with me

Subscribe, rate and review the podcast in iTunes

Rate and review the podcast on Stitcher

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September 8, 2019
HPH255 : How do you specify high performance windows? – with Chris Herring

Chris Herring, Director at Green Building Store, explains why careful consideration should be given when specifying windows.

Interview with Chris Herring

With a father who was a keen environmentalist, Chris was raised with an awareness of ecological issues from a young age. A builder by trade he has been in the industry since the 1980s and is now a director at Green Building Store.

Windows aren’t just another building element, they’re a critical one

Chris emphasises how important it is to get the right windows on a building project. They matter to the feel of the house and how we feel in the house.

They have physical and architectural functions, they’re part of the fabric and the thermal performance, there are safety issues in that you need to be able to get out of them, they might have to protect against fire, and obviously let light in.

When it comes to specifying windows and bringing all that together, many of those functions can actually be in conflict with one another. Often it can be a case of finding the best compromise.

Manufacturers and suppliers should be part of the design process

With components and performance levels in buildings becoming more complex, Chris would like to see manufacturers and suppliers becoming more part of the team. They can bring their expertise at an earlier point and be more involved in helping to specify the right windows for the job.

Triple glazing as standard

Chris says that with a little more attention to detail and extra skill, a building can, and should, be made considerably better. With the thermal envelope key to the performance of the building, triple glazing should be standard in the UK climate to make it work.

“So, we need triple glazing because the Passivhaus Standard drives us there, and it drives us there because the building physics drives us there. The key to that is, in many ways, comfort, because we need every surface to be warm. Because then we don’t need to heat the building very much. As soon as you get a cold spot, you’re going to get mould, you’re going to get discomfort, you’ve got down-drafting, you’ve got all these problems. So, the system stops working. So, it’s the building as part of the system that drives us to triple glazing in this climate.”

Determine the energy balance

There is more energy loss from windows than any other part of the fabric of a building. Their thermal transmission will always be a weak point, but they do also bring solar heat into the building. That energy balance between the gain and the losses is what’s so significant with windows.

Being around 10-15% of the area of the building, they typically make up a disproportionate amount (roughly 30%) of the losses.

If you’re north facing you have no significant energy balance. It’s just a loss so the logic then would be to have small windows.

With a Passivhaus, it’s about looking at how to get the best balance between those window heat losses and gains, and typically they’re approximately in balance, so are neutral in their effect.

Understand their performance

Chris thinks it’s worth taking time to understand a little bit about these values so you can understand more about the performance, rather than just being led by someone else.

U-value: the heat loss through the piece of glass – measured as the heat loss per metre squared per degree kelvin difference between inside and outside. So, watts per metre squared K (W/m²K).

A measurement can also be taken for the heat loss through the window frame (usually worse than through the glass).

The Psi-value is the heat that is lost through the edge of the glass where it meets the frame. That is measured as a heat loss per metre perimeter of glass.

Those three factors, the frame value, the glass value and the Psi value, are added together to give the U-value of the total window.

Each window will have a different U-value so they are all modelled separately in PHPP.

G-value: this is the measurement of how much solar gain actually gets through the glass. The more panes and coatings there are, the more you restrict the amount of sun that can get through.

In a triple-glazed window it would likely be in the 50-60% range. In double-glazed it might be around 70%, and in single-glazed closer to 80-90%.

Lambda-values: this relates to thermal conductivity. It applies to every material and is actually the inherent quality of the material.

“Obviously, if we take a piece of aluminium or a piece of expanded polystyrene, they’ve got very different amounts of thermal conductivity, the amount that heat can get through per metre thickness of that material. So, a λ-value is given as the heat loss, which is given in watts, per metre thickness of the material per degree difference between the inside and the outside. So, that’s watts per metre K (W/mK). So, the metre is the thickness of the material.
It’s quite different from the U-value, which is about an area value, if you like; it’s per metre squared. And we’ll use that thermal conductivity to then calculate the U-value.”

PHPP calculates the U-value

Chris explains that PHPP has a standard calculation which takes the heat loss from the glass, the heat loss from the edge of the glass and the heat loss from the frame, and adds them together. It calculates the total heat loss and gives the U-value of the window.

PHPP also builds in the Psi-value for the installation, which is given as the heat loss per metre perimeter of the window. To get the installed value for the window, that heat loss is added to the total heat loss of the window. The calculation shows how important it is that the window is installed properly, and the implications for if it’s not. A triple-glazed window installed badly for example, could effectively end up with the performance of a double-glazed unit.

“So, that detailing is incredibly important and something people struggle with and architects struggle with.
Coming back to what the suppliers and manufacturers offer, I think this extra value of supporting people further, supporting architects, supporting clients, is actually critical. I think it will become more and more important for suppliers to add those extra values to supply. It’s not just a widget that’s somebody else’s problem how they fit it, the supplier should be going further down the chain and advising people how to fit it and helping them to get that detailing right.”

Understand risks of overheating

While PHPP gives an idea of overheating across the whole building, it doesn’t differentiate by room. Understanding some of the causes can be helpful. A full height window for example, while perhaps desired architecturally, won’t increase the light level a great deal because you’re only lighting quite a small area (it’s higher light that has more effect in terms of lighting the building). However, it will result in increased overheating because it’s still heating the floor up fairly close to the window, and that’s heating the room up.

Trying to get round that by using shading would need a much bigger overhang to fully shade the window, which is probably unlikely to be used. So in that case, although the overhang can be shading the top half of the window, the bottom half going down to the floor is not shaded and will result in overheating.

Something else to bear in mind is that a window above 800mm from the floor doesn’t require safety glazing, which can make considerable cost savings.

Timber-clad windows are recommended

Green Building Store made the decision some years ago that triple glazed would be the only window they would offer, but there are different types of cladding. They don’t engage very much in the conversation around uPVC windows because the evidence they’ve seen shows how environmentally damaging they are.

There are also questions around the environmental impact of aluminium clad windows. The energy use in smelting and even recycling aluminium is quite high.

“We’ve always tended to encourage people to go to non-aluminium clad windows because we think that the evidence seems to show that it lowers the environmental impact of the window. We have bowed to demand, if you like, and now offer aluminium clad as well.”

Timber windows do need painting every 10 years and adding up that expense will probably make it similar to the cost of aluminium cladding. But what most suppliers won’t tell you is that the aluminium cladding will fade over time and you will likely lose the appearance within 20 or 30 years.

“If people come to us and ask for aluminium clad, we’ll give them aluminium clad. If they want to discuss the issues then we’ll certainly discuss that with them. And we do outline some of that information on our website as well, so that people can think about those issues.”

Find out more

Visit the website of Green Building Store

Follow Green Building Store on Twitter

Transcript

Download a transcript of the interview with Chris-Herring.

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June 19, 2019
HPH193 : Should you specify uPVC windows? – with Simon Corbey from ASBP

Simon Corbey from ASBP shares some of his research into the costs and life cycle of plastic windows and suggests some considerations for self-builders.

Interview with Simon Corbey

Simon Corbey worked as a chartered surveyor in the ‘90s, and went on to become a specialist in natural paints for London’s first eco builders’ merchant, Construction Resources. He has also worked for BioRegional, the Sustainable Development Foundation, the Good Homes Alliance and the Alliance for Sustainable Building Products (ASBP). Last time we spoke to Simon, he talked to us about healthy building products.

We should question the chemicals in uPVC

Simon Corbey has been working on behalf of the ASBP to compare plastic and timber windows. Consumers tend to be more concerned with how windows will look and last than where plastic comes from and the issues around it. Simon remarks that plastic windows are manufactured widely in the UK, but these impacts are not really considered, adding, “I do think that there’s an opportunity for the UK to develop their building physics and approaches to making windows.”

Simon notes that plastic windows appeal, as they are generally cheaper and available in a range of styles. He describes the marketing as aggressive, adding, “It’s well funded, of course. It’s the petrochemical industry.” Plastic windows contain a range of chemicals but no research has suggested a negative effect on indoor air quality. The window itself may be benign, but Simon has also been researching product manufacture and life cycle.

Manufacturing chlorine is hugely energy intensive

Simon explains that uPVC (unplasticized polyvinyl chloride) contains chlorine. Used in swimming pools and our water supply, it’s common enough to not raise concern. However, he explains that its manufacture has an incredible impact on the environment.

Simon estimates that producing 80% of the UK’s chlorine uses more electricity than Liverpool. Production of PVC in Europe in 2015 used 8.6 million tonnes of chlorine. “So it’s hugely energy intensive,” says Simon, adding, “From a life cycle analysis it’s a terrible, terrible thing.”

Simon’s research shows the hidden costs of uPVC windows

Simon has further researched Ineos, who produce most of the UK’s chlorine. Describing it as “a very murky world,” he says he feels motivated to bring this to people’s attention. The site of the Ineos plant in Cheshire is of particular concern. Simon describes how Ineos were caught dumping mercury into the Manchester Ship Canal in 2014 and the land contains a dump once used to “make everything from nuclear weapons to World War II stuff”.

Previously owned by ICI, the dump was linked to toxic chemical leaching and reports of ill health in the early 2000s. Today, explains Simon, if you look at the Land Registry, this dump apparently has no owner. “There is a completely toxic dump just there which the council don’t own,” he says. “Ineos have somehow redrawn the lines of their site and conveniently they don’t own it any longer.”

Timber windows struggle to compete on price and marketing

Despite their significant environmental price, plastic windows remain cost effective for manufacturers. The price of oil and gas is still low, making the raw materials cheap. The process of gathering timber, processing, sawing and milling it is quite energy intensive in comparison and the end product is heavier to transport. All of this adds to cost.

Simon further points out that the UK timber industry is quite fragmented, containing many different disparate interests. Conversely the plastics industry markets products with “one voice”, typified by slick campaigns, such as that for Everest windows. Moreover, Simon describes it as quite litigious, recalling a threat of court action when his former employer persuaded a Scottish Housing Association to cancel their order for plastic windows.

Plastic windows may not outlast timber

There is a perception that timber windows will rot, requiring repeated maintenance, while plastic is assumed to be tougher. Simon questions these preconceptions. While acknowledging that timber windows have a finite life cycle he points out that plastic windows are prone to yellowing after a while. Simon himself has 120-year-old timber windows, which are “going strong”. “They’re a bit leaky,” he says, “but they’re okay as far as I’m concerned.”

Other options for window materials do exist. Simon recommends considering factors such as product life cycle and building location. Aluminium is very durable but highly energy intensive; composite timber and aluminium windows are one alternative.

The quality of UK timber windows is improving

Windows are an essential part of the building fabric’s performance. With improvements in building science, double glazed and triple glazed windows are appropriate for new builds and both plastic and timber windows can achieve Passivhaus Trust certification.

Where good indoor air quality is maintained by natural ventilation, windows must function well, being easy to open and clean. There have been some issues of quality with some timber windows but Simon sees this improving, following the standard of European and Scandinavian manufacturers.

Recycling plastic windows involves additional expense, chemicals and risks

The Scottish Civic Trust suggests that the recycling rate for windows might be 3% and according to the Green Guide, BRE suggest that the UK average is about 15%. However, Simon suggests the many issues with recycling, such as the chemicals and risks involved, make that figure optimistic.

The formulation of plastic has changed quite a lot since the ‘60s and the industry has made great attempts to clean itself up. Substances considered by REACH to be of very high concern, such as lead and cadmium, are being phased out although tiny quantities are still allowed.

Plastic is worse than wooden windows in a fire

Simon believes that toxicity is a huge issue. He confirms that plastic windows pose a greater risk than wooden ones in the event of a fire and believes that more research is needed. However, currently all the testing institutes are very busy “as a result of Grenfell”.

Simon notes that in the USA, The Healthy Building Network has liaised with the Fire & Safety community to argue for a complete halt to use of plastic products. Likewise, the ASBP has initiated contact with Kent Fire and Rescue and the London Fire Brigade. As Simon explains, “there is some research underway but it’s early doors, I would suggest, this type of testing.”

Industry and consumers are moving away from plastic

Techniques and attitudes continue to change. Acetylated wood is an example where window science has improved. This process basically uses vinegar to extend the maintenance life of timber to over 60 years.

Simon notes a growing interest in health and wellbeing, as well as a global campaign against plastics. He summarises, “I think at ASBP we’re trying to suggest that as a society we’ve just got to start using less plastic through and through, in all the things that we do and windows being one of those things.”

Find out more

Visit the website of the Alliance for Sustainable Building Products (ASBP)

Follow the ASBP on Bluesky

Transcript

Download a transcript of the interview with Simon Corbey

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October 3, 2017
HPH188 : What are Paragraph 80 builds and how do they work? – with Richard Hawkes from Hawkes Architecture
Richard Hawkes from Hawkes Architecture tells us about the exceptional circumstances in which planning for rural new builds may be granted.

*Since recording this podcast, the government has updated the National Planning Policy Framework. ‘Paragraph 55’ (or ‘Para 55’) policy changed in name to ‘Paragraph 79’ and then ‘Paragraph 80′, although the content remains largely unchanged. *

We have amended the show notes but the interview will still talk about Paragraph 55.

Interview with Richard Hawkes

Richard Hawkes’ self-build, Crossway, helped launch his own practice Hawkes Architecture nine years ago. Before that he worked at a large commercial practice in London.

As planning is rarely granted for new rural homes, Richard had to learn what circumstances were considered exceptions. His expertise then led to work gaining planning consent for others in similar circumstances. Nowadays Richard even sits on a Design Review Panel, made up of professionals including landscape architects and engineers, that advises planners whether or not a proposal is meeting policy.

Crossway

Planning policy allows rural development in exceptional circumstances

Paragraph 79 has four special circumstances that can permit a new dwelling in the countryside:
1. An agricultural worker’s dwelling. It’s quite difficult to create a business case for these so they don’t happen very often.
2. Re-use of a heritage asset, e.g. saving a listed building.
3. Re-use of redundant farm buildings. Relaxation of permitted development legislation has made this moot for now.
4. If the dwelling is of exceptional quality or innovative in its nature of design. All of Richard’s Paragraph 79 projects fall into this last category.
Four tests determine if a design is sufficiently exceptional

For a dwelling to be of exceptional quality or innovative in its nature of design, it has to pass all of these tests:
- Help to raise the standards of design more generally in rural areas
- Be of the highest standards in architecture
- Significantly enhance the immediate setting
- Be sensitive to the defining characteristics of the local area
Hawkhurst

Paragraph 79 is an important design-led policy

Since Planning’s introduction in 1946, there has been a reluctance to approve new homes in the countryside. Green Belt, Areas of Outstanding Natural Beauty (AONB), Heritage Coast and other designations evidence this. Even Paragraph 79, which Richard describes as a piece of national policy originally introduced in 1997 to enable landowners to get permission for their “English country house”, states that planning authorities should generally seek to resist new dwellings.

In 2003 the Labour government sought to get rid of (then) Paragraph 55 which they felt was an elitist policy, but were lobbied by the Royal Institute of British Architects (RIBA) who argued the policy would move forward dwelling design. As a result, the policy evolved into PPS 7, Paragraph 11 and actually used the term ‘contemporary architecture’.

The policy recognises the mediocrity of typical dwelling design, and has a practical significance in terms of architects’ professional development. It encourages them to learn how to respond to a setting and produce amazing buildings. Richard explains that the principles of good design can be looked at entirely objectively, even if people’s responses to design are inherently subjective.

Sustainability must be factored into the design

A beautiful house isn’t enough. A house of the highest standards in architecture will incorporate lots of insulation, heat recovery ventilation, triple-glazing, and passive solar gain. Richard describes these Passivhaus principles as just sensible design and something planners would expect to see in a Paragraph 79 scheme, not reasons why they would grant consent.

The nature of the site and its management will often tie in to the energy strategy they develop for each individual building.

West Pearroc

There are different types of Paragraph 79 house

Some locations suit a contrasting building, like an English country house. Richard describes this as unapologetically “dominating its landscape. Enhancing it but very much in contrast to it.”

Conversely, one of his own Paragraph 79 houses on a Green Belt / AONB site needed to show sensitivity to the defining characteristics of the local area and significantly enhance the immediate setting. His architecture enhanced the farmstead by reinforcing the positive qualities of stable buildings on the site while removing other buildings that were “detractors”.

Likelihood of planning consent must first be weighed up

Richard’s team must first establish whether the site has the right ingredients to get a planning consent. He uses the analogy of a set of weighing scales, and there are several factors weighing down the ‘wrong side’:
- You’re not allowed to build a house in the open countryside.
- In Green Belt, there is the principle of openness. If the site has other buildings on it, you can potentially look at “consolidating building form” as a strategy. If there are no buildings there at all, it becomes very difficult.
- AONB are protected by National Policy. It is possible, but more complex as these are highly protected pieces of land.
- If it’s a Site of Special Scientific Interest (SSSI) or on top of a hill, any development is likely to have a big visual impact.
No one can guarantee planning consent, so Richard tries to manage that risk. To “balance the scales” he carries out a rigorous analysis of local and national policy to find benefits that could come with a scheme.

The landscape and architecture have to work together

Assuming there’s a robust enough case to proceed, Paragraph 79 applications are not for the faint-hearted; they represent a big investment on the client’s part and are about the land as much as the house. It takes months before Richard will even know what they’re designing.

Time is spent with landscape architects and commissioning reports and surveys to adequately understand the ecology, biodiversity and resources of the site. This long process uncovers minute details about animals, sun, prevailing wind direction, climate and geology.

Richard explains that involving a landscape architect right at the start helps them to lay down some rules about the site: sensitivities to avoid and opportunities to embrace. The ‘master plan’ is holistic and everything included in the plan can be justified.

Examples of ways to enhance the landscape might include:
- Binding the site together with areas of woodland
- Linking habitats
- Bolstering woodland edge
- Introducing wildflower areas and a proper mowing regime to increase biodiversity
- Putting management plans in place
Flight Farm

Designs reflect a rigorous understanding of the site and client

The practice’s design framework originates from Richard’s self-build experience. He developed the design for Crossway using two distinct, parallel processes. Firstly, responding to the client (his wife) meant considering the “mechanics of a plan”. These are things like securing the best views, ensuring low running costs, opening up the house to the south, etc. A client lifestyle analysis is done, including everything from what time they wake up to how often they entertain.

The other process is analysing how the landscape changes as you approach the plot from different directions, to determine what the house needs to do sculpturally to respond to each of the views. This was something Richard did intuitively with his piece of land: “For me, the context of any site has got rich things for you to respond to. You’ve just got to find them.”

The design then emerges from these two processes. Crossway’s distinctive arch grew from a desire for the house to sit in amongst the ecology and the biodiversity of the land. And the design for one client project interpreted the qualities of the local flint to respond to the “defining characteristics of the local area”; the building is sharp and crisp outside, like the inside of flint but the white, soft-flowing curves of the courtyard evoke the outside of the stone.

Crossway

We need to keep pushing house design forward

As well as acting as a good training mechanism for architects, Richard has a philosophical argument for protecting Paragraph 79. “If the policy weren’t there, I’d find that quite a sad reflection on where we are with design, where we are as a country with architecture. Look at all these houses going up with no aspirational policy there. I’d find that quite a sad place to be and quite short-sighted.”

Find out more

Visit the website of Hawkes Architecture

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Transcript

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August 24, 2017

HPH172 : The impact of setting your energy target – with John Palmer from Enhabit

John Palmer from Enhabit explains what happens if you choose not to go all the way to Passivhaus standard, including how this impacts on cost, energy efficiency and comfort. He also outlines a best practice approach if you are going to build with Passivhaus principles.

Interview with John Palmer

John is the Managing Director of Enhabit, a company that helps to improve building performance, efficiency and comfort levels. John is a qualified Passivhaus consultant, SAP and BRE Assessor, systems engineer and experienced project manager. Prior to joining Enhabit, he ran his own low energy design consultancy.

First understand the implications of Passivhaus for your project

If you are trying to set an energy target, John’s advice is to start by reviewing your plans in line with Passivhaus standards. This will allow you to fully appreciate what it might take to achieve Passivhaus. Once the implications are understood, you may take the necessary steps or make a conscious decision to compromise and aim slightly lower.

Invest in professional advice at the design stage

John says that Passivhaus is not so much more complicated than a normal build, it just requires more thought at the beginning. One of the key thermal bridges to eliminate or mitigate is where the ground floor meets external walls, which will require careful detailing and potentially some specialist materials. Paying for some extra time with your architect or Passivhaus consultant is a worthwhile investment.

When clients commission a design review with Enhabit, they are shown a Passivhaus model of their design and given graduated options to see what’s possible with their house and how close they can get to Passivhaus, with indicative costs for extra requirements.

Focus on a fabric first approach, not eco technology

John says it’s easy to get bamboozled by all the technology available. Ground source heat pumps, solar panels, boilers, etc. all have a design life of around 20-25 years and will need to be replaced. However the walls of your building will be there for 80-100 years, so the extra investment you put into them at the start will repay itself time and time again.

Architectural aspirations may make Passivhaus harder to achieve

John explains that in Passivhaus terms, the shape of your house is the ratio of your liveable area to outside heat loss area. So you may need to compromise on an ambitious design if you want to target Passivhaus.

If your plans have already incorporated professional advice, and you intend to follow a very high-performing fabric first approach, it may be you just need to add in a MVHR (mechanical ventilation with heat recovery) system.

Alternatively you may find you haven’t gone far enough with the fabric of the building and need to change the specification of insulation, glazing, etc. This is typical of retrofits, where John says it’s quite hard to achieve the levels required for Passivhaus with the existing fabric.

Heating a Passivhaus costs a very small amount

The annual space heating demand in a Passivhaus should be no more than 15 kilowatt hours per metre squared per year. John comments that this is a very specific number and you may decide this is unachievable.

The key is to understand what number you can get down to, and what that means. For example, a target of 30 kWh will cost you twice as much to heat your property in any given year than it would have done if it were a Passivhaus. But heating a Passivhaus costs very little, so doubling very little isn’t that much and is likely to be better than other new build properties in the UK.

Every design decision will impact on comfort levels

Doubling your space heating demand to 30 kWh will impact on comfort but the nature of this impact will depend on why you haven’t achieved the Passivhaus target of 15 kWh. John gives a few examples:

Issue	Implications	Impact On Comfort
Insufficient insulation in walls	Heat loss from walls	Feeling cold off the walls
Poor detailing where walls meet ground floor	Thermal bridging	If bad, noticeable cold spots and possible condensation/mould
Window specification isn’t triple/ high-quality double glazing	Cold will radiate off the glazing	Feeling cold in rooms at certain times of year

Thermal comfort is all about constant temperatures

Many homes, especially Victorian buildings, tend to have rooms that are hot near the ceilings but cold at lower levels due to drafts and a lack of insulation below the ground floor. John explains that although the average air temperature in the room might be ok, having cold feet and a hot head will feel uncomfortable! Paying attention to thermal bridges and insulation will help to achieve what John calls good temperature stratification.

Building regulations rely on people opening windows for required ventilation

Although our awareness of temperature is quite good, it’s harder to detect poor air quality. We may notice smells and detect when rooms are a bit stuffy, but that’s about it.

Humidity, VOCs (volatile organic compounds), odours and nitrogen oxide levels are all examples of pollutants within buildings. John advises we need about 30 cubic metres of fresh air per person per hour moving through a property to deal with pollutants, but this isn’t achievable with trickle vents and extractor fans unless you start opening windows.

An MVHR system will deliver the required level of ventilation, but there are other mechanisms out there superior to extractor fans that will give extra ventilation but perhaps not cost as much.

Insulation, glazing and ventilation will cost more, but not much more

These three aspects are typically more expensive than a normal new build, as a Passivhaus requires:

More insulation – but you’ll only be paying more for materials (approx. 0.5% increase on overall cost); the labour costs are the same
Triple glazing, for thermal performance and to avoid condensation and mould – the gap is closing between triple and double glazing prices
An MVHR system – for an average sized house this may cost £9-10k for supply and installation

Of these, the greatest return on investment will be insulation.

Some builders are willing to learn

Hiring the right people to build a Passivhaus is another factor to consider. Although it’s still relatively new to the UK, John has found that builders relish the challenge of doing something that requires more detail and thought; they appreciate the ability to measure how well they’ve done, and revel in achieving the standard. He adds, “You have big, hairy builders hugging each other on site when they get their final air test and they’ve got down to the right levels.”

Five helpful tips from John

1) Visit a Passivhaus or speak to someone who lives in one, to see what it can deliver from a living experience

2) Find out what would be involved in achieving Passivhaus for your project

3) Understand how each decision affects the final design, floor space, efficiency and comfort

4) Put an MVHR system in, regardless of your airtightness target; ventilation and air quality are worth doing as standalone

5) Have some form of quality control in place, even if you’re not targeting Passivhaus, to get the results you’re expecting

Find out more

Passivhaus Trust

Transcript

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April 12, 2017

HPH134 : A new build cavity wall Passivhaus – with Angie and Paul Dallas
Angie and Paul Dallas explain why they opted for a Passivhaus, and the benefits of getting involved with the build.

Interview with Angie and Paul Dallas

Angie and Paul had been looking to build a comfortable, energy efficient house that they could retire in. There was no issue with finding land as their existing house had enough land available, albeit with its own planning challenges.

It took 5 years to be granted planning permission

Angie says that the planners weren’t necessarily against their plans, but the Highways department had to consider the problem of access because of the limited number of houses that could be on their unadopted road. The house is in a conservation area so that presented its own challenges, and there were a number of trees in their garden which had preservation orders on them.

After initially having their application rejected, they won on appeal in London.

A planning consultant helped with the process but in hindsight they think they should have appointed him earlier and benefited from his expertise in areas where their architect was struggling.

The decision to build to Passivhaus standard was taken after planning permission had been granted

It was on a trip to look for triple glazed windows that Paul started chatting with one of the directors of the Green Building Store who explained the differences that Passivhaus had from normal building practices. Coming away from that meeting Paul was convinced that, even if they didn’t strive for the full Passivhaus standard, he wanted the building to at least use the principles of high design quality.

Deciding to pursue this approach meant some design changes to their original plans. The amount of glazing had to be adjusted together with the orientation, but the actual size and construction wasn’t altered.

Being involved in the construction had its benefits

It had always been important to Paul to be actively involved in the construction of his house, however once the decision had been made for Green Building Store to take on the project to Passivhaus standard he was unsure what his role would be because his knowledge of the area was limited.

Whether Paul would be able to assist with the labouring was a decision for the building team, and Paul was careful to take his time and show that he could muck in and not be a pushy owner. Eventually he was invited to join the team and he relished learning on the job and taking their instruction.

One of the greatest challenges that Paul found was working on the site throughout the British winter. If the roof could have gone on during the summer months it would have been a much easier build.

A key benefit of Paul being on site was that if a problem arose or a decision needed making, he understood what was going on and could make the choice straightaway.

Paul found the camaraderie of being on site extremely enjoyable and believes the pride in the house afterwards far outweighs the efforts of doing it.

“And to be honest I don’t think I’ve ever laughed as much during a job ever. I thought it was great fun.”

The comfort of the house has lived up to their expectations

The temperature of the house remains fairly constant and the mechanical ventilation heat recovery system means that the air quality is good everywhere. Angie also notes that it seems to stay cleaner and that since having pollen filters put in she has also seen health benefits compared with their old house.

Take time to appoint your design team

Their first architect, although designing a great scheme, didn’t have the time to take it from there. Paul and Angie wish they had taken time to research, interview and appoint a replacement architect but instead they appointed someone on recommendation, who professed to be an architect but actually wasn’t. He claimed that the original plans couldn’t be built, but it took Angie and Paul several months (and £6,000) to have the courage to dismiss him and get somebody else. Thankfully the next architect they appointed confirmed that they would be able to build to their original plans. Paul emphasises the importance of researching specialists and finding someone that you feel comfortable with.

“If you’re building a Passivhaus you want somebody with experience of Passivhaus or at least is willing to learn and look at the differences between that and a normal house and take those on board.”

Deciding to use the services of an interior designer they were fortunate to have them involved at an early stage to assist with the layout of the interior and pick up on areas, such as space for hanging curtains, which would have been difficult to rectify after the construction work had been completed.

Green Building Store provided them with knowledgeable and skilled builders who Angie and Paul both say were a pleasure to work with. They used their own electrician and were also happy with the services of the plumber.

Paul stresses that it’s important to take your time at the stage of getting your team together. They were thankful that their whole team worked well together and that they enjoyed working with them.

“And it’s people you can work with as well. It’s not just a good track record but if you’re not comfortable with those people then it’s going to be a problem down the line.”

Find out more

Visit the website of Green Building Store

Check out the shortlist for the 2016 UK Passivhaus Awards

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June 22, 2016
HPH103 : Is Building a Passivhaus Expensive? – with Geoff and Kate Tunstall
Geoff and Kate Tunstall explain how they were able to create a fantastic Passivhaus in Denby Dale with a budget of around £150,000.

Interview with Geoff and Kate Tunstall

When Geoff and Kate decided to self-build and downsize for their retirement, their first idea was to build a dormer bungalow with a conservatory. Following a conversation with Green Building Store, they were encouraged to explore Passivhaus as an option.

Back in 2008 there weren’t any examples of Passivhaus in the UK that they could visit, so they travelled to Austria. After visiting two properties there which had temperatures of 20/21 degrees, despite outside temperatures of -4 degrees, they made the decision that if they could afford it, this was how they wanted to build.

Paying a Ransom Strip Demand Used Up Their Contingency Budget

The plot for their build was at the bottom of the garden of their existing house. Unfortunately a builder had bought the plot of land behind this and, based on the value of the plot, demanded £30,000 for a six inch ransom strip that they needed to provide them with access from their building to the road behind. After a year of fighting this, and the builder realising that the money was their contingency so it was this or nothing, they eventually agreed to pay a total of £18,000, which used up their contingency before the build had even started.

During that year however, the designs for the house were all researched and finalised to the extent that as soon as the ransom strip issue had been resolved they were able to progress straight away with the build.

Making a 3D Model Helped Their Understanding of the Scale and Spaces

Originally they wanted to build a bungalow but the plot size didn’t make this feasible. Kate found it useful to create a 3D model out of balsa wood to get a better idea of how well furnishings would fit and how comfortable the spaces were likely to feel. They also found using the model was a helpful way of explaining their ideas to the building team throughout the process.

An Important Feature was to Have Light and Warmth Throughout the Fabric of the House

Particularly because their last property was a dark and draughty cottage, Geoff and Kate were keen to build a warm and contemporary home with lots of natural light. They had to abandon their original conservatory idea after running it through PHPP, but instead they remodelled it to feature a two-storey solar space which beams the light throughout the house.

Using Kate’s 3D model they realised that one of the bedroom windows seemed uncomfortably small. Again using PHPP the design could be changed to accommodate a larger window by adding higher performance floor insulation to compensate.

Keeping Within Budget was a Collaborative Process

From the outset, everyone knew the budget was only around £140,000. With regular meetings between themselves and the design team throughout the design process and the build, they were able to keep on top of what was happening, when, and how much things were going to cost.

Living on site was a help because they were able to spot any little details that needed changing before the build progressed too far and became too expensive to amend.

Geoff explains that on a Passivhaus there are certain non-negotiable things that need to be budgeted for and for which there are no short cuts, such as triple glazing and the ducting for the MVHR. Where they saved money was by spending time researching things like inexpensive lighting and kitchen units.

“But it was a good discipline for the Green Building Store and ourselves to actually work to a figure, a limited figure, because it proves that Passivhauses can be built to a reasonable budget. And the budget for our house isn’t a lot for what we’ve got.”

The Build Wasn’t Without its Challenges!

One of the biggest challenges they faced was building throughout one of the coldest winters in a generation. It was too cold to use the paint they had planned, mould spores started showing on the clay plaster and they had to put up a screen so they could continue working in the howling gales and snow.

A further challenge was the corner windows of the solar space, both from a Passivhaus point of view but also a structural one. They needed to make sure there wouldn’t be too much solar gain, and also ensure that the structural support would be inside the thermal envelope.

The House Exceeds Expectations

Geoff and Kate have been living in their house for around five years. They wanted a house that could be kept clean easily, that would provide warmth when needed, that would be energy efficient and not amass big fuel bills during their retirement. It has achieved all of these and something which Kate hadn’t focussed on before they started was how important it is to have a healthy house. She describes it as being a calm, tranquil and healthy place which will benefit them in their old age!

One of the Passivhaus buildings they visited in Austria had some underfloor heating so Geoff and Kate assumed they should put it in their kitchen and bathroom. In hindsight they didn’t need to as it’s actually never been used.

Geoff is adamant that anyone embarking on a self-build project should go and visit a Passivhaus. Once they’ve experienced it he’s quite sure that’s how they will then go on to build. He says that even if the initial outlay is a little more expensive, it will pay for itself within three or four years, and be future proofed against rising fuel prices.

Find Out More

Find out more about Denby Dale in the Green Building Store blog.

Transcript

Download a transcript of the interview with Geoff and Kate Tunstall.

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October 13, 2015
HPH038 : What Type of Windows Do You Need in a Passivhaus? – with Bronwyn Barry from One Sky Homes
Bronwyn Barry from One Sky Homes explains the evolution of windows and why modern windows are really pieces of equipment. She also shares what’s involved when it comes to choosing high performance windows for a project.

Interview with Bronwyn Barry

Bronwyn Barry is originally from South Africa but she studied architecture in America and never left!

Her passion is for integrating good design with comfort and performance. When Bronwyn discovered Passivhaus, she felt it had the whole package.

The Smartwin window system

Windows Have Become More Sophisticated Over Time

A window traditionally has two functions. Firstly it lets in light or air, and secondly it allows the dweller to see outside (or vice versa).

In a high performance building, the windows are likely to be the weakest link in the chain when the whole building envelope is considered. So how the windows are built and how they are designed into the envelope is critical to making the full package work.

Historically Windows Have Even Told Stories!

Early windows were just tiny openings in buildings with no glass. As glass became more available, windows even became a status symbol for the wealthy.

Bronwyn talks about the glass tax in Ireland where people were taxed on the number of windows they had!

Gothic cathedrals really pushed the boundaries of what windows were, using them to tell biblical stories.

Building Science is Nothing New

Bronwyn reflects on a trip to Frankfurt in Germany where she visited the Goethe House. On the top floor are the original leaded glass single pane windows from the 1600s which have a channel at the base and weep holes to allow the interior condensation that would form to drain to the outside.

Bronwyn found this fascinating that building science was being used to come up with solutions centuries ago.

Domestic Markets for High Performance Windows are Growing

When Ben asks whether a Passivhaus needs different windows to any other building, Bronwyn says not necessarily. However, the windows must be very carefully designed and selected, taking in account the climate, orientation of the building and the materials.

The good news is that there’s more and more choice on the market. While imports (from countries such as Austria and Germany) have dominated Passivhaus projects in recent years, local producers have cottoned onto the growing market and have started producing appropriate windows and even customised products for their specific markets.

Windows Need to Function Differently According to the Project

There are variables to take into account such as the solar access of the site. The energy balance will change according to the size of the building. Taller buildings, multi-family units etc. will have large internal gains compared to relatively small gains on single family, detached residences.

Bronwyn explains with an example of one of her recent projects which had no solar access: “I’ve recently done a retrofit where our windows weren’t net energy producers. What I mean by that is the overall energy gain from the solar gain of the windows was actually less than the amount of energy that gets lost out of the windows, just because they are a weak insulation component in your full envelope. That was in California, where we’ve got really great solar access and a relatively mild climate but this was a project that had a whole line of redwoods across the southern border of the property completely shading the house. So we really had to choose our windows that would give us lots of natural light, which people still always want no matter where you are on the planet, and wouldn’t lose too much heat and maintain a relatively comfortable interior temperature.”

Aesthetics Tend to Come First When Choosing a Window

In Bronwyn’s experience choosing windows for a project generally follows this sequence:
1. Select the ones you like the look of
2. Look at the performance data to see they are adequate
3. Consider the price
Another factor to bear in mind is what materials the windows are made from. Some people do not want any uPVC on their projects!

Glazing Selection has a Big Impact on Heat Gains

The glass that is chosen to go in the frame has a huge influence on how much heat gain there will be from that window. Again, this is due to a combination of factors.

For example, quite often there are double pane or triple pane. There are a variety of films and coatings that can be applied to the glass too. Different gas fills can also go in between the panes, adding an extra layer of insulation.

Do Gas Fills Leak Out Over Time?

Ben raises the concern that these gas fills in the windows may not last and Bronwyn responds that in a recent study of a 10-year old window it was found that only a very small amount of the gas had escaped.

There is currently debate that at high altitudes this could be more of a problem but even then there are workarounds.

Bronwyn says: “If your glazing panel already has very poor performing spaces, so if they’re aluminium spaces holding the two panes apart that’s already probably a worse thermal bridge kind of heat loss opportunity than no gas in the window. And if your frame is a really poorly insulated frame that’s another bigger opportunity for worse heat loss. Then if the installation, how the window’s installed within the wall opening, if that has all sorts of metal pans that go from the inside to the exterior and big air leaks there again is another bigger offender.”

Rough opening framing with air-sealing tape

Everybody in the Chain of Custody has to do a Good Job

It is not a case of just buying a really high performance window and the job is done, because if it is put in a sub-optimum position in the wall or is not sealed properly to the building fabric, the overall performance will be diminished. So it is very much a team effort. Good communication and a little education can go a long way.

As Passivhaus requires a blower door test it quickly reveals any poor workmanship, both in the production of the window and the installation.

Solar Gains Need to be Carefully Controlled

With the opportunity for windows to be great solar gain mechanisms they essentially become the heating system for these buildings. However, if this is not controlled carefully it will become an over-heater for a building which is also not desirable.

This was Bronwyn’s childhood experience in South Africa, where overheating and being uncomfortable from excessive heat was more the issue rather than lack of heat.

So being able to shade the windows carefully and control the solar gain is just as critical as the window design and where they are located in the building envelope.

Exterior operable shades in Berkeley, CA

Your Shading Mechanism Should be a Long Term Proposition

There are various shading mechanisms that can be used on a project such as an eaves overhang and brise soleil to exterior louvered blinds or a neighbouring building. Even trees can be used as part of your strategy. The important point is that it is a lasting solution.

On high rise buildings it can actually be a coating on the glass itself that modulates the solar gain.

Balance Project, New Mexico (Image courtesy Jonah Stanford)

The Importance of the Window Frame is Often Over-Looked

While architects and energy modellers can get engrossed in the glass specification the actual frame design itself can get skimmed over. The frame can make or break a high performance window.

The glass can be replaced and most manufacturers provide a good selection of glass inserts but when it comes to the frame there are normally only a few options.

That’s why Bronwyn’s top tip is to pay attention to how well a window is put together and also how it drains at the sill.

Transcript

Download a transcript of the interview with Bronwyn Barry.

Our Question for the Comments Section

How have you chosen windows?

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December 18, 2013
HPH023 : A Cottage Built with Structural Insulated Panels (SIPs) – with Kingsley Barraclough (Client Case Study)
Kingsley Barraclough shares his experience of building a house and explains why he decided to use structural insulated panels (SIPs).

Interview with Kingsley Barraclough

Kingsley’s background as a plumber has given him plenty of opportunities to see houses losing heat and that’s why he was determined to build himself an energy efficient home. So, his goal was to create a small, flexible space with lots of natural light, that was easy to run and also cheap to heat. The new cottage would have a floor area of 125m²and be built on a plot beside his existing property.

Despite Construction Experience, Kingsley Chose to be Just the Client!

Although Kingsley’s an experienced plumber he did not do any of the work himself, reasoning that it would not be a good idea to change the dynamic of a team that already works well together. He also hired a project manager because he believed that while he can work in a team, he did not have the necessary skills required to run a team and deal with the many things that can go wrong!

Hiring a Contract Administrator Made Dealings Simple

Kingsley took the advice of his project manager and hired a contract administrator. This effective third party acts as a membrane between client and builder, and provides some neutral ground should any problems arise. Kingsley says that it worked well for both parties.

Initially Kingsley Discussed The Outcomes He Wanted to Achieve with His Architect

Kingsley’s first step was to sit down with an architect and talk through what he wanted to achieve from the new house. Whereas his existing home was from 1884 and had lots of nooks and small rooms, in contrast he was keen to create a more contiguous living space.

The SIPs are Engineered to Suit the Design

Once a design was created and planning permission acquired, Kingsley had to decide on a build method. After researching structural insulated panels as an option and visiting houses that had been built with them, he chose this route. An engineer then reworked the SIPs method of construction to fit with the design. For example, where the timber panels were not suitable the engineer reinforced it with steel construction to achieve the required look. At no point did Kingsley have to compromise with the SIPs.

A Structural Insulated Panel is Like a Sandwich!

Kingsley talks about the structural insulated panels he used which consist of 2 layers of OSB with a core of PIR foam. [An additional 25mm insulation, TW55, was also added to these Kingspan Tek panels on the inside behind the plasterboard lining, which proved very cost effective.] Once machined these panels form part of a kit, which turns up labelled and numbered. There are rebates, grooves and fillers that lock all the panels together.

SIPs are Incredibly Quick to Put Up

With the hard work done in a factory, one key advantage of SIPs is that they can be assembled on site very quickly. In this case, the ground floor was done in the first week and the second floor was done in the second week.

The Precision of SIPs is Greater Than a Conventional Build

Having been in the trade for many years, Kingsley says the nature of block and breeze construction means you tend to work to the nearest inch. However, with SIPs you are working to about 3mm.

SIPs Allow You to Work on Two Faces at Once

Once the timber cell has been put up the services can be going on inside – pipework, electrics, etc. – while brick work or cladding can be underway on the exterior. Wet trades are not crossing paths with the services.

Kingsley Presented His Intentions to His Neighbours

Kingsley wanted his house to be a comfy fit for everyone in the area and so he negotiated with the people either side about the aspect, size of the building, etc. As someone who really values his neighbours, presenting his intentions at every stage of the project worked very well.

The Cladding Needs No Maintenance

Two thirds of the face work is in a cottage mix of bricks (three local bricks that are used randomly) and then one third has got a modern version of weatherboard, which is a concrete board, called Eternit board (made by Marley). It gives the impression of being wood but is good for minimising heat losses and also will never need to be painted.

The SIPs Hold up the Bricks!

Kingsley points out that the brickwork – the face work – is attached to the SIPs with brick ties in the conventional way, so it’s not just held there by gravity. It is secured in the same way that brick to breeze block is secured, but really the SIPs panels hold up the bricks, not the other way around.

Buying Windows From Abroad was Cheaper

Kingsley put a lot of effort into finding window frames. The triple-glazed ones he eventually bought were dramatically less than getting them locally. Kingsley does not understand why this is.

Put Your Money into the Fabric of the Building

After considering many options including Huf Haus, but trying to temper budgets and reality, Kingsley ended up concluding that the money is better spent making sure you don’t need energy than in having very fancy low cost energy. So he put a lot of effort and money into making sure he doesn’t lose heat in the first place (rather than having a cheap source of it).

Minimise Your Dependence on Technology

Kingsley did not invest in heat pumps or other renewables because he thought they were too expensive and he didn’t want to have the worry of maintaining them as he got older. The thought of claiming on warranties of companies in 10 years for £30,000 bits of kit somewhere in the ground was something he wanted to avoid.

The House is a Hermetically Sealed Box

Although the appearance may be conventional, the house is airtight and very well insulated. It uses an air management system (mechanical ventilation with heat recovery) to bring in new atomised air but without the heat losses. 80% of the heat of the expelled air is saved and there is a full air change in the house every hour and a half.

Installing Cabling for PV Means it Could be Easily Added Later

A modern high efficiency condensing gas boiler drives the underfloor heating and the hot water, etc. Plus there is a cylinder that will accept solar and cabling to allow for PV at a later stage. Kingsley has no plans to install renewable technology but if efficiencies continue to improve, he wants to make sure he can add them retrospectively (without having to change cylinders and knock holes in the walls to add wires, etc.).

Coordinating the Utilities Proved Difficult

Although Kingsley could get the gas and water companies to be pretty cooperative, he really struggled with UK Power Networks. Kingsley’s advice, for anybody doing a new build in the UK, would be to get that bit applied for at the same time as you get your planning permission. There is a 90 days notice period, even from when they say yes! And this does not necessarily mean they arrive on the 91st day. So, organising this is a priority because not having electricity reliably is going to be a problem. Kingsley says having a contract administrator really helped.

Life is Much Easier When All The Contractors Want the Same Outcome

Kingsley believes he was very fortunate to have a team that shared his vision and all clicked together. He gives the example how if his interior designer came up with a good idea for the kitchen, the person building the kitchen would readily help to achieve it. There were no hidden agendas.

Having Builders Who Got on With the Neighbours Helped

Kingsley was very pleased with his team and thought it was fantastic to have builders that put themselves out to get on with his neighbours. He says this set the flavour for the build and eased pressure points with parking, etc.

House designed by Martin Roberts from Cubed Projects

Transcript

Download a transcript of the interview with Kingsley Barraclough.

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Elrond Burrell on Home Style Green

Elrond Burrell is a guest on the Home Style Green podcast. He gave a really good explanation of the Passivhaus standard (the comfort standard). Check out episode 30: Is Passivhaus relevant to New Zealand?

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May 22, 2013