Tag: straw

HPH378: Accessibility for all – with Guy Harris

Guy Harris from AccessiblePRS explains why accessible housing is important, what the key considerations are and how to deliver it well. He also shares his experience of designing his own house as a wheelchair user.

Interview with Guy Harris

Guy Harris is the Director of AccessiblePRS, which he founded in 2020 to increase the supply of wheelchair accessible rental homes. He became a wheelchair user in 2003 after an accident and now works to promote good accessible design for all buildings.

Accessibility is the ability to move around a home at all stages of life

Quite often the terms accessibility and adaptability are used interchangeably, and people will even have their own understanding of what they mean. So Guy defines accessibility as the flow and space of a home, and the ability to move around it at all stages of life. This can be as parents with young kids, older people, wheelchair users, people who have dementia, and so on. Accessibility is understanding how we relate to our spaces and making them human centred.

Accessible spaces can benefit everyone

Guy believes that making accessibility about the person with a disability is fundamentally flawed, because it means we bring all our negative stereotypes and misconceptions to that approach. Instead of being a burden this can be playful, glorious or liberating for a whole range of people.

“When I tell stories about where accessibility is in place, very often, I tell them about people who have no disability at all, and show them the advantages, so that we can understand that this really is not for some people, this is for all people.”

Wheelchair users face constant frustrations from existing properties

In 2003 Guy made a mistake when crossing the road and was struck by a lorry. From that point he became a wheelchair user.

Like his, most disabilities are acquired and this made him realise that he had been part of the problem before his injury. He worked on property projects, and it was only after the accident that he understood the constant frustrations for wheelchair users around property, which also gave him an insight to the opportunities.

Funnily enough, before his accident, Guy had bought a 1000 square feet shell apartment in London, which he made into an aspirational and indulgent space. It was only afterwards that he realised he’d actually designed a wheelchair accessible space. However, he admits he wasn’t in the wheelchair accessible mindset at the time. The Disability Discrimination Act had just come in, which meant that sockets and switches had to be at a specific height. He remembers clearly saying, “I don’t have a disability, I don’t want them at this height, I’m not doing it.” He sees a nice juxtaposition there, both wilfully not wanting to do anything around disability, whilst on the other hand designing the perfect space for it.

Building for accessibility requires a mindset shift

While we have made significant advances in gender equality, eliminating racial discrimination, and LGBTQ+ rights, Guys says that disability feels like the poor cousin.

Until we get over our subconscious fear around what it means, what it looks like, and not wanting to believe that it can ever happen to us, we’re always going to have an issue with the idea of building accessibly.

Guy feels we either need to change our relationship with disability, or perhaps with the language around accessibility. Accessibility is simply good design.

No one will come into this home and go, “Wow look at that accessibility.” It really features disability in a wonderful way. You come in and you go, “Hey, wow, look at this home.”

Key requirements for wheelchair users are more space, a level home, step-free access and a purpose designed bathroom

As a wheelchair user Guy needs things to be designed in a certain way to be able to live autonomously and independently. He needs a bit of space, wider doors and consideration of how they’re positioned relative to things that come next to them, whether it’s cupboards or walls. Step-free access is also important, which might include lifts or ramps. Bathrooms are a critical room, often a wet room, and a hoist may be needed.

By designing for a wheelchair user, you design for any eventuality in life.

You don’t need a specialist architect for a house build

Guy’s architect wasn’t a specialist in disability or accessibility but was amazing. He drew the brief out of them carefully, in the same way that he would for any other client, considering how they lived and wanted to live.

One aspect that really helped Guy was a study trip, visiting existing properties and trying to absorb useful information.

“People make decisions without actually seeing what they’re making decisions on, which is nuts, frankly. And so the more we got to see different things and understand the implications and the benefits and the costs, the more we naturally arrived at the decisions we made.”

There will be opportunities in the design process

The design process didn’t revolve around the wheelchair, but as they went along, they realised that there were opportunities coming from their discussions. For example, the spine wall down the middle of the property, has quite a few structural posts. These created alcoves and space to put furniture, but also were the perfect place for handholds.

The house evolved into an ecological build through the design process

Guy explains that they were starting with a blank sheet and ecological architecture or doing something green, was an obvious question to ask, although at that point he really didn’t know what it meant. He did some investigating but wasn’t getting anywhere until he heard a sustainability consultant talk at a show and he’d never heard anyone speak so much common sense about how to build. She then recommended the architect, who he eventually hired.

“We arrived at straw, having said the only thing I know I don’t want is straw!”

After two separate non tangible experiences they decided to build with straw. The first happened in Scotland when they visited a straw bale building. It was blowing a hoolie outside and because Guy is paralysed, he doesn’t feel his legs, but his legs started to tingle in a warm, cosy, enjoyable way. They then went to the property next door, which was a different build and a nice layout, but it just felt cold, without the same richness.

This prompted them to visit another straw build, Haringey Community Centre in London. At the time Guy’s wife was pregnant and wasn’t really enjoying the pregnancy, nausea, low blood pressure, always moving from side to side. But inside the centre he noticed she was standing still and looked comfortable. As soon as they went back outside the nausea started again, but when they came back inside it stopped. There was no way of understanding what it was, but on two separate occasions they had both experienced this magical feeling, and so it became a no-brainer to build with straw.

Accessible homes don’t have to be ‘Grand Designs’ projects

Guy is aware that his bespoke home might be considered a grand design style building, but accessibility can be achieved at most scales.

Aspects Guy particularly enjoys is the volume of the internal space and how light is brought into the property from all directions. There’s a strong connection to the wooded area outside.

Their choice bio-based materials has delivered on many levels

Guy’s home is a load-bearing straw bale house, with bales almost being used like bricks. On the inside natural clay plaster is applied directly to the straw, whilst the outside is lime render.

The house has an organic, natural feel whilst still being mainly straight lines with a few nice curves and subtle colours. For Guy the house feels grounded and is peaceful and calm inside. The design is largely open plan, which allows them to be doing things together in the same space, but also when doing things separately they somehow still feel connected.

“I think one of the subtle things about the house is how when you’re in it, everything feels right.“

Look at the value of what you build rather than the cost

Guy wishes there was more consideration around value rather than looking purely at cost. Building the cheapest possible home is unlikely to deliver a good outcome. As someone who works in property, Guy understands that the budget could be spent in a million different ways. For example, they could have had more space for the money or built more quickly, or spent less, but that was not the priority.

The materials they were using and how they were building was important, and he was taking a long-term view. Guy intends to stay in this house for the rest of his life, so the initial cost will balance out over that time. This is a quality-of-life investment.

An accessible entrance

Make sure you get good advice when building for accessibility

Building and designing homes is an expensive business and it’s easy to make mistakes around accessibility, so Guy suggests getting external input when required.

“If you want to design for more possibilities, take advice. If you want to, I don’t know, have specific sound or acoustic attributes or engineering attributes, you pay for advice.”

He shares a couple of examples of how planning upfront can help you avoid problems further down the line.

He stresses that it is important to consider how the walls, doors and windows relate to each other. How you create the ratios and the space, your floor surfaces and the furniture that you need. Bathrooms are an expensive room that need designing properly, because retrofitting a standard bathroom to accommodate grab rails or a ceiling track hoist, could mean starting again from scratch.

Another scenario is with sliding patio doors, which may not open all the way, meaning the opening is then less than a wheelchair width. Or you put a ramp in but have forgotten that you need a level platform on both sides. These are simple things, but they matter and so paying for advice could help prevent costly mistakes.

“In every design meeting, just ask the questions, what can I do? What if? What does it look like? What does that mean? Have we thought about? Do you know about? And take it from there, because even the simplest of questions will inform the design and make people think.”

The regulations are helpful but provide minimum standards

Guy says that, for the most part, the regulations are extremely helpful. However they are open to interpretation and deal with minimum standards. If you have a designer who doesn’t understand the intention behind the regulations, they can interpret them, sometimes in bizarre ways which mean the regulations have been met but are meaningless. And for Guy when we aim for minimum standards, we nearly always fail. Good design is about understanding what is actually needed and designing for that. If you go for best practice, then the regulations are almost guidelines. Experience and advice will steer you much further.

There is a National Register of Accessibility Consultants, NRAC, and those are people who have experience of designing for accessibility. A consultant can come in at the beginning, at the design phase, be part of those conversations and reviews, and support your architect in optimising the design.

We should be designing for an ageing population

By 2040 there’ll be more people in the UK aged 65 or over than there will be of working age, which for Guy, begs two questions. One, where are they going to live? And two, who’s going to look after them? The only feasible answer at the moment is an end-of-life residential care setting, which he thinks is going to be quite grisly for a lot of people.

It’s already common to find that newly injured people with disabilities get stuck in hospital, because there’s no accessible accommodation available.

So if you have the opportunity to create your own home, it’s a good idea to consider future needs. Otherwise you may face a situation, an illness or a disability, and you won’t be able to cope and you’ll be forced to move out.

Communities should be able to house us all

Guy feels that in the UK we put accessibility in a silo like all the other housing issues, such as affordable homes and green homes, whereas accessibility could cut across all the silos. He suggests every design meeting should ask questions around accessibility to inform the design and make people think.

He gives an example where his architect was working on a community project in Scotland, designing holiday lets in a woodland setting. Initially they were not thinking about accessibility, but when they embraced it several things happened.

The first thing they realised was that by designing the bathroom for accessibility it helped with the modular design and made things flow. The second thing was by making the route from the car park to the homes suitable for wheelchairs they could get a small telehandler to the construction area. This saved time and money when moving materials and the process went more smoothly. The third thing was the community realised that if any of them had an accident or got injured and needed accessible accommodation they would now be able to stay in the community rather than having to move out.

For Guy this is an important point to highlight. Traditionally we’ve always included everyone in a community. We really need to get back to that understanding of what community means.

“One of the things I love to do is show beautiful, accessible design, because I think that’s where people suddenly start to get it and realise that it’s not clinical, institutional, ugly, it’s actually something that nourishes and enhances our lives.”

Find out more

AccessiblePRS

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May 21, 2025
HPH365: Becoming a housing activist – with Cypren Edmunds

Cypren Edmunds, a housing activist and advocate for bio-based building materials, describes the challenges he has faced living in social housing in London, and the health benefits and energy efficiency that can be achieved through building with straw.

Interview with Cypren Edmunds

Cypren is the Chairperson of Strawbale Building UK and the President of the European Strawbuilding Association, and is working to increase the use of straw and other bio-based products within the construction industry.

Cypren has first-hand experience of living in UK housing that is not fit for purpose and the affect this has on family life and the wider fabric of society. He believes we need much more education within the construction industry and society at large to enable us to build healthier and more energy-efficient homes.

Activism begins with a burning desire to make a difference

Cypren describes how living with his family in a property that had damp and condensation became distressing, and drove him to become a housing activist and ultimately to change his career. He started by re-igniting the Residents Association for his housing estate, but quickly realised that collectively they didn’t really have the knowledge of the built environment, planning and housing regulations to get to the core of the problems they were all facing. Cypren, a qualified carpenter, was working in fitness training at the time, but decided to change direction and see what he could do.

Activism requires upskilling and plenty of time

Cypren knocked on doors to find out just how bad the situation was for residents. In one of the worst cases, water was dripping from the light bulb above the resident’s head and as you walked through his flat, every single wall was dripping with condensation and mould. The resident had complained to both the Housing Association and Local Authority, but nothing had happened.

A wall riddled with damp and mould

The fabric of the buildings is concrete and steel (with fan heating) with no apparent strategy for dealing with ventilation, so moisture becomes trapped. The Housing Association didn’t have any solutions, apart from leaving windows open or putting in noisy dehumidifiers, neither of which worked well for residents.

Keep communicating and stay engaged with all parties

Rather than getting aggressive the Residents Association genuinely wanted to stay positive and work with the Housing Association and the Local Authority to identify solutions. As the Housing Association had already carried out surveys of the building, they too realised how bad the situation was and that it needed addressing. However they admitted they didn’t have the money for a full retrofit, so after much consultation tenants voted for regeneration.

Cypren outlines the role of the Residents Association in explaining the wider picture to residents and wading through the multitude of facts and information provided by the authorities. Many people didn’t understand the bigger picture, only how things related to them, and this is a political problem that needs to be addressed.

“We don’t have enough skilled professionals, at all levels, in the construction sector to undertake the kind of retrofit work necessary for these types of properties.”

Council houses in North Kesteven

Low carbon bio-based materials have many benefits

Whilst straw was rejected as a material for the regeneration of Cypren’s housing estate it is being used widely across Europe in the construction of a variety of public and private buildings.

As President for the European Straw Building Association and chair the Strawbale UK, Cypren is working to get the message across politically and digging into policy and regulations to increase use of bio-based materials in construction.

A firestation in Colombey Les Belles, France

Meliana day care centre in Valencia, Spain

Countries like Lithuania and France are way ahead of the UK in recognising the value of straw and other bio-based materials. The French have entrenched this methodology into their regulations. For example policy RE 2020 is an environmental regulation that came into effect in 2022 with the goal of improving energy efficiency and reducing greenhouse gas emissions. Cypren points out that we just don’t have this in the UK, and whilst groups like ACAN are doing a great job of delivering that message we need much more.

STBA and SPAB hold a joint conference

We need more education around the use of straw

Cypren is clear that in the UK we need a significant drive to enable people to understand the value of using straw and other bio-based materials within the construction industry and that this drive should come from Government. There is a lack of education within the construction industry itself and many myths around straw that make the public wary of its use.

Get input from experienced natural builders

As with any material or methodology it’s essential to understand how you work with bio-based materials and how it differs to other approaches so make sure you’re learning or engaging with experienced natural builders. The good news is that straw is not a difficult material with which to work, particularly if you’re already a plasterer or carpenter, etc. The skills necessary are just the same as you would need if you were going to build a timber framed house. And now with prefabricated straw panel systems it is even easier, with construction on site taking just a few weeks.

Highly engineered straw panels at Old Holloway

Cypren believes we need to be building more with straw panels and developing factories to produce them. This would be good for the economy and generate jobs. We’re told the construction sector is struggling, so let’s train young people to work with materials that are helping us to move forward in life. It’s up to the government to give the appropriate incentives to those large housing developers to incentivise them to build in that way. We should take inspiration from France. Cypren tells us of a conference last year, where the French were saying they’d just built over 10,000 homes with straw. He couldn’t say how many we have built in this country.

Intelligent activism could help create better homes and communities

Cypren feels that if we are not happy with the situation within our community, we need to work together to create change. For him it’s not about going on marches or rallies it’s about engaging with the authorities, commenting on consultations, and making sure your voice is heard. He believes we have a tendency in England to sit back and expect others to sort things out. Instead, he suggests we find like-minded individuals, share ideas, speak to experts to get the information needed and become active with our community.

For us to have a healthier society, we need to be thinking of everyone. There is a knock-on effect for example for young people living in poor housing, who are ashamed to take friends home, with no youth centre to go to, and so they hang around outside and potentially become involved in anti-social behaviour. If homes are comfortable and inviting people will want to be there instead.

Keep an open mind to bio-based materials

Cypren’s overriding message is to keep an open mind to bio-based materials. He says there is massive potential to scale up and that it would enhance all of our lives.

From all of the data and all of the reports Cypren has seen, people who live in straw buildings or own bio-based buildings tend to be happier and healthier.

Querbeet Housing Project in Lüneburg, Germany

Find out more

Sustainable Traditional Buildings Alliance

European Straw Building Association

Straw Bale Building UK

The Society for the Protection of Ancient Buildings

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November 20, 2024
HPH351: Creating affordable, high quality, low carbon homes – with Linda Farrow
Linda Farrow from Agile Homes explains how their prefabricated panelised system can deliver high quality and truly affordable homes that are good for the planet.

Interview with Linda Farrow

Linda Farrow and her partner Craig White set up Agile Homes in 2019 to address the need for better housing in the UK. They aim to deliver low-cost homes without sacrificing on quality, and each of their buildings is low carbon, energy efficient and has the ability to be disassembled easily (at the end of its life cycle).

Timber panels with straw in-fill are made off site

Linda explains that at the core of an Agile Home is their Modern Methods of Construction (MMC) panelised system. These panels are prefabricated in a factory and then assembled quickly on site, giving you a watertight structure within a day or two. The use of natural materials like timber and straw ensures that the homes have an extremely low embodied carbon and the panelised nature of the system mean it can be easily customised to meet the client’s needs. This makes it incredibly versatile and can be used for a variety of projects, from a block of flats to a one bedroom bungalow.

Their housing model aims to overcome common challenges

Linda explains that as part of their mission to make good quality and affordable housing accessible in the UK, they needed to identify the current barriers in the construction industry and come up with creative solutions to overcome them.

There is a cultural wariness of adopting renewable materials

England has a romance with brick and block construction that is proving tricky to shift. Even our children’s stories have perpetuated this message by telling us that a house made out of brick will be sturdy whereas a house built from straw and sticks will leave us vulnerable to attack.

This cultural mindset shift will take time to change but as more projects are completed it will keep demonstrating how well natural materials can work.

There is a lack of affordable land to develop

The price of land is currently a major barrier for affordable housing projects and often takes up a large proportion of the budget.

By collaborating with councils, housing associations and charities, Agile Homes works to unlock land at low or no cost for social value. This can quickly reduce the delivery cost by around a third.

It needs to be easier to finance and insure sustainable projects

It can still be a challenge to finance or insure ecological projects because they are deemed higher risk.

So Agile Homes has invested time in developing relationships with companies such as the Ecology Building Society and they are now an approved supplier.

They also gained BOPAS (Build Off-site Property Assurance Scheme) accreditation which is recognised by mortgage lenders as providing the necessary assurance that properties that use modern methods of construction (MMC) will be readily mortgageable for a minimum of 60 years.

Gaining planning consent is not always straightforward

Getting planning permission for a project can be quite involved and take time, which is why Agile Homes have developed a modular solution called TAM which complies with the Caravan Act. This generally means planning permission will not be required because they are moveable rather than permanent structures.

TAM (Transportable Accommodation Module) is a rapid response housing solution

TAM is a prefabricated, rapid-response housing solution.

The modules can be transported ‘flatpack’ to site and assembled quickly, leaving you with a watertight shell in a day or two and operational within a few weeks. Depending on the site and the needs of the client, TAM can also be umbilical to an existing building, using the same power, water and drainage systems without the need for planning permission.

“We’re not quite there yet, but one of our aims is to make it as easy for individuals and community led organisations to buy into our system as if they were going to a car showroom, and they can sign the finance agreement and drive away in their car. So in the same vein, they could sign a finance agreement and have their TAM delivered to their site”

Delivering a ‘turnkey’ solution helps to maintain quality

The larger the development the more likely it is that different companies and sub-contractors will be delivering different aspects. Inevitably this can lead to mistakes or inconsistencies. So at Agile Homes, where possible, they like to control the whole process.

“In essence it’s about control, and making sure that we can deliver the quality of product to the client. If you use a conventional procurement method where you’ve got the design and then you transfer over to a main contractor, the main contractor is incentivised to find all manner of ways to reduce their costs and increase their margin. And that’s not a criticism, that’s just the way the system is set up. We are a values led organisation and our board scrutinises everything that we do carefully. So I think it is about aligning everything that we do with our core value of respect for people and planet. It’s about control throughout the process to make sure that we can deliver to that time after time for our clients.”

LILAC in Leeds

Prefabrication can take place at a ‘pop-up’ factory

The panelised system has been designed so that it can be put together with high end power tools. In certain circumstances – such as at the request of a community led project – they can bring the manufacturing closer to site and create a pop-up factory in empty barns or industrial units. This has the added benefit of upskilling communities who are interested in sustainable building.

The Agile team

The best collaborators have respect for people and planet

“The ideal client would be someone whose values align with ours, so respect for people and planet, someone who has access to substantial amounts of patient capital, who is like us, genuinely interested in providing as many people as possible with homes that are affordable in perpetuity. Because having an affordable home, a safe civil space to be in is the foundation stone, in our view, for sustainable regenerative communities. And climate change is quite rapidly going to be a question of water and food crisis. So there are many, many immense challenges on the horizon for society. We want someone who, like us is very focused on helping society to put in place the foundation stone for us to then have the capacity to deal constructively with all the challenges that are yet to come.”

Inter-governmental policy is needed to be able to deliver widespread affordable housing

Linda explains that the biggest challenge for Agile Homes is access to patient capital and limitations caused by a lack of inter-governmental collaboration on housing policy.

“Governments have a duty in between terms and outside of party political allegiances to look after human beings and the planet. There are some policies that should be negotiated and agreed as being inter governmental.”

The natural materials contribute to a calm environment

Agile Homes has carried out work for local authorities, housing associations and charities, and quite a lot of their residents are vulnerable. This can range from physical disabilities, mental health issues to learning disabilities. So some key feedback they have received is that the natural materials and quality design have created a calm atmosphere which can be of great comfort to anyone but particularly to those with special needs or mental health challenges.

Agile Homes are committed to sustainability from their build system to their business model

Linda explains that Agile Homes aims to create a business model for affordable housing by looking at a wide range of resources which promote sustainability and social value:
- UN Sustainable Development Goals
- Five Capitals Model from Form for the future
- Doughnut Economics
- Small is Beautiful by E. F. Schumacher
- Cradle to Cradle
- Bill McDonough
The Agile Homes team is also in the process of finalising their Carbon and Social Value Tokens, which will allow people to offset their carbon emissions in local, sustainable, social developments.

“We’ve been thinking a lot about how to we evidence and generate revenue from the carbon storage that we’re achieving in our buildings and also in the social value that we’re creating. So we’ve been doing work behind the scenes to build calculators and we’re just about to go live with what we call carbon and social value tokens that can potentially be traded. What that means is that we have found clients who are interested in actually buying and paying for the stored carbon and the generated social value as part of their ESG governance systems and processes. So rather than offsetting their carbon footprint by paying for X 1000 trees, in a plantation 1000s of miles away, they’re choosing to buy the carbon that we can evidence is being stored for a minimum 60 year design life in our buildings and I think that’s very exciting. We have plans to use that methodology to generate revenue that can then further reduce the costs of some of our schemes for our most vulnerable clients. We’re really excited about that extension to the model and that rethinking of how do we generate value and revenue in a truly regenerative economy?”

Find out more

Visit the website of Agile Homes

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May 8, 2024
HPH346: Passivhaus homes where cooling is a key consideration – with Andy Marlow
Andy Marlow from Envirotecture explains why Passivhaus homes are a good fit for most climates in Australia, how they approach these projects and what is needed beyond shading to keep the homes comfortable when the outdoor temperatures soar.

Interview with Andy Marlow

Ben Adam-Smith has started this year with a visit to see his brother in Australia and, naturally, it was a great opportunity to record some more podcasts.

On his previous visit he caught up with sustainability expert Michael Mobbs and Clare Parry who was then Director of the Australian Passivhaus Association.

On this trip Ben has three more interviews. In this episode we meet Andy Marlow, Director at Envirotecture, who designed Sydney’s first Passivhaus in Thornleigh in 2018. He has since been involved in numerous new build and EnerPHit projects, all of which require an element of cooling. In today’s chat, Andy gives us an insight into Australia’s current housing stock, explains why Passivhaus is a logical choice for creating healthy and comfortable homes, and he outlines the main ways to incorporate cooling into a Passivhaus build.

The ‘look’ of a home tells you nothing about its quality

Andy describes the majority of Australia’s houses as “fancy looking sheds”.

With a warmer climate in many parts of the country there is a culture of opening all the doors and windows, and creating a wonderful indoor/outdoor lifestyle! In reality, temperatures are frequently unpleasant as is the humidity and, due to the poor standard of construction, there is no refuge indoors.

In fact most houses in Australia will rely on mechanical cooling via ducted air conditioning units. Because the houses are poorly insulated, the coolth generated often escapes the house, meaning that these systems operate incredibly inefficiently.

Andy also points out that Australia not only builds the largest houses in the world with the national average being 244 square metres (3x the UK average) but also the cheapest per square metre. This poses quite a challenge for the uptake of Passivhaus because it is going to be slightly more expensive than a traditional build which may in turn lead you to reduce the floor area (which many Australians may not be keen to do).

A skills shortage is impacting the quality of homes

Australia is also facing a skills shortage in the construction industry because of a nationwide shift towards higher education. Whilst this has many other benefits, the impacts on construction means it can be harder to find contractors and with less competition, they are able to charge a higher price for a lower standard of work. This is not the case for everyone or everywhere in Australia, but Andy does think this has had a significant impact on the quality of the current housing stock.

Huff n’ Puffhaus – Strawbale construction method

In some climates cooling will be required

Although the Passivhaus methodology is the same no matter where you are in the world, in Sydney’s climate the challenge is more about cooling than heating.

Good design can reduce the risk of overheating

Andy explains that carefully placed and smaller windows can have a big impact in reducing the need for cooling. Likewise shading from an eaves overhang or external blinds will help. Natural cooling and cross ventilation by opening tilt turn windows can also work if temperatures drop overnight. However, it is not uncommon for Australia to reach 40 degrees, so there is often also a need for mechanical cooling systems.

“The biggest practical issue that we face as architects and designers in Australia is the expectation around the size of windows and doors. A lot of it comes back to that indoor/outdoor lifestyle and people’s desires, expectations, and beliefs around that. Basically, you hit a point where it doesn’t matter how good the glass is or how good your eaves are, you start needing to use external blinds or things that are directly adjacent to the window to keep the sun off them. You also just hit a point where regardless, there’s just too much glass.”

When looking at cooling, energy efficiency is key

Because of the efficiency of Passivhaus homes, they can work very well in partnership with air conditioning systems. In much of the current housing stock, air conditioning units supply the cool air to each room of the house through a duct system. Due to the fact that these houses are poorly insulated, a large proportion of this cool air is lost though the walls, ceiling, etc. making the whole system inefficient. The high performance fabric of a Passivhaus means very little of this cool air will be lost and as a result, the cold air can be delivered in one or two areas and spread throughout the whole house naturally or through the ventilation system.

“Every one of the certified Passivhauses that we’ve done have mechanical cooling. It’s very, very common here. 86% of new houses in Australia have mechanical cooling.”

On top of this, the MVHR removes the heat from the fresh, incoming air but retains the coolth from inside the house. This massively reduces the amount of energy needed to cool a house. With higher temperatures every year as a result of climate change, Passivhaus is an excellent option to reduce the energy demand and keep homes cool.

Design drawings and ventilation plans for Thornleigh Passivhaus

A Passivhaus will be comfortable in all climates

Andy explains that they always design their Passivhaus homes to stay between 20-25 degree celsius internally, but some clients may ease off on the cooling, save a bit of money and just live in a slightly warmer house. It’s down to personal preference.

There is a big range of outdoor temperatures in Australia (over the course of the year) and it is common for most parts to reach 40 degrees during the day at some point, possibly reducing to 5 degrees at night during the coldest times. However, there are also areas in the mountains that can get down to -10 degrees so each project must take into account the local climate data.

Health and comfort benefits are key drivers

Most of Andy’s clients have been people who have lived abroad and experienced the standard of housing in other countries. In returning to Australia, they realise how low the standard is in the current housing stock and set out on new build or retrofit projects to try and change this.

“It’s the hardest part of everything we do without a shadow of a doubt, we joke that 5% of our job is design and the 95% is making stuff happen. It’s mostly successfully sold when people comprehend the benefits and the benefits have nothing to do with the money. It’s mostly around the health and comfort. That’s partly because of the quality of everything else that exists: if I don’t do this, what will I end up with? And the answer to that is normally too hot, too cold, too mouldy. If you don’t want that, you end up in this long discussion, which concludes you need to build something that looks remarkably like a Passivhaus.”

Sydney’s first Passivhaus: Thornleigh

Andy worked to deliver Sydney’s first Passivhaus in 2018:

“It’s in the middle of suburban Sydney. It’s got a massive five metre wide north facing window in it. Interestingly, it’s got no eaves on it, which was a deliberate choice, but it’s got external blinds on it. We did it for a whole host of reasons, to get as much solar gain as we could in winter and the blinds give us real control during the summer. They come at a price obviously, but everything in building comes at a price. However, they also require the occupants to use them, so there’s no point having a blind if someone doesn’t press the button for it to come down. These clients are incredibly active in the management of the house, so it works like a charm.”

Renewables are common, energy efficiency is not

A large proportion of Australia’s houses are fitted with solar PVs and the majority of new builds have them as a requirement, which is economical for a country with so much sun. However, with an inefficient housing stock they are consuming a lot of energy every day. The challenge is therefore not solely focused on how energy is generated but also how much is consumed.

“A lot of big inefficient houses with big air conditioners, while they might make a lot of electricity at various points, in the middle of big electricity spikes, they’re going to struggle. But also when the system crashes, then they’re completely stuffed.”

There has been a recent shift towards batteries as people are deciding to prioritise personal resilience, but also because the feed-in tariffs supplied by energy companies have dropped quite significantly and it no longer feels worth it. If Passivhaus became mainstream in Australia, the combination of energy-efficient homes and personal renewable resilience would put them in an excellent position to face incoming climate challenges.

The conversation around embodied carbon

Andy highlights that in Australia, the national conversation on embodied carbon is behind the curve. There is a reliance on concrete for building foundations and the houses are often large. However, the default approach to building is with timber frame meaning they don’t face the same challenge as the UK in needing to transition away from brick and block construction.

Huff n’ Puffhaus: Straw bale construction process

The Australian construction industry relies on imported materials

Australia imports a lot of supplies for low energy projects and as a result 80% of a house might need to be sourced elsewhere. Materials such as glass, insulation, membranes, mechanical ventilation systems/ducting and any new technological developments are all brought into the country and are therefore expensive items. Australia does have a large timber industry so wood is more easily accessible but there is still a reliance on imports to meet demand.

Some materials that are commonly used in the UK such as I-joists are not as needed in Australia because their buildings don’t require as much insulation. Andy notes that 140mm stud walls often offer a sufficient wall thickness in order to meet Passivhaus standard. Wood fibre board would be a great material for Australian Passivhauses to eliminate thermal bridges but it is bulky and as a result expensive to import.

Design approaches: new build and retrofit

Andy explains the process he would take when beginning a Passivhaus project:
1. Design brief – Setting the parameters for what we are trying to achieve. Why are you doing this? What do you want? And for retrofit, what’s wrong with the house right now?
2. Work out the practical details – What is the building going to look like? How is it going to get built? Is it a professional builder or a self build project?
3. Design development phase – Get as many details as possible in place as early as possible because once it has been taken to planning, it can be hard to change.
4. Post planning – Focus on the detailing, construction documentation and refining interiors.
“We spend a lot of time getting our interiors to absolutely sing because that’s the stuff you end up looking at every day.”

New builds go pretty smoothly. The most common time for issues to arise is during groundworks when something is uncovered that no one knew about, but most of the time the process is smooth. In the case of retrofit projects, Andy explains that he prefers to wait until the building has been stripped back to work out the specifics of the technical design as you never know what you will find hidden behind the walls. There have been many occasions where this stage has uncovered issues that show their original plan wouldn’t work and a different approach was needed. Andy recommends creating an overarching design which includes the materials you plan to use before you begin to dismantle the existing structure so you have an idea, but to avoid trying to plan out specific construction methods or details before this step, as you will likely end up having to repeat the process.

Envirotecture currently have 2 EnerPHit projects certified and many more in the works.

Thornleigh Passivhaus: Internal water tank feature

Recommendation is still the best way to find good builders

Envirotecture has developed relationships with a number of builders over the years and so that will tend to be the first avenue they explore. However if you are going into a new area, Andy follows these three steps:
1. Seek recommendations from people you know and trust.
2. Use the list of certified tradespeople on the Australian Passivhaus Association database.
3. If the other two steps have been fruitless, ring people in the area and ask a “dumb question” that will highlight how much they really know about Passivhaus – this will help you find the people who buy into the approach and commit to the attention to detail necessary.
The team you assemble doesn’t necessarily need Passivhaus experience, but they do need to be enthusiastic and have an interest in learning.

Knowledge is key

Andy offered some overarching advice to anyone who might want to take on a Passivhaus project:

“Knowing as much as you can before you start is the key. Ask lots of questions of people who should know decent answers and if you don’t understand the answer, ask the same person again. If it still doesn’t make sense, ask someone else. The more competent professionals you surround yourself with, the easier that’s going to be. It is significantly cheaper, and easier and less stressful to learn from other people’s mistakes, I would recommend leveraging them as much as possible. You will make some of your own, everyone does, realise them as quickly as you can, learn, move on, try not to do it twice!”

Find out more

Visit the website of Envirotecture and follow along on their blog for more updates

Follow Envirotecture on Instagram and Linkdin

Special thanks to Ruth Butler for connecting us with Andy – Listen to Ruth’s episode here: HPH177

Transcript

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February 28, 2024
HPH089 : Can You Build to Passivhaus Standard Using Only Natural Materials? – with Bjørn Kierulf from Createrra
Bjørn Kierulf from Createrra explains how you can have the best of both worlds, using almost entirely natural materials to create a house that reaches the Passivhaus Standard.

Bjorn-Kierulf from Createrra

Interview with Bjørn Kierulf

Bjørn is an industrial designer and his wife is an architect, and together they run Createrra.

They have always been into building with natural materials, but now have adapted their approach to achieve Passivhaus Standard as well.

Natural Materials are Often Good Insulators

Most natural materials are fibrous and as such tend to be good insulators. They also have protection against summer overheating, though do need to be protected from humidity and moisture.

In order to reach high levels of insulation, however, a greater thickness of the material will be required (compared to artificial insulations such as aerogel).

Straw has the Ability to Take Structural Loads

When compressed, straw has very good insulation values and unlike most other materials also has the ability to take structural loads. While there are a number of load-bearing straw houses the structural calculations can be quite difficult which is why timber is usually used as well.

A further benefit is that it can be added to the compost heap, rather than landfill, when the building is demolished!

A Straw Bale House is Not a Flammable One!

Fire needs air, but straw bales are so densely pressed that there is no air to burn. When combined with a typical clay plaster it can have a 2-hour fire protection, meaning that even with a 1000 degree fire burning for 2 hours on the inside, there is no noticeable temperature difference on the outside.

Copyright Strawbuild

A Danger of Lime Render is High Water Absorption

Lime render is typically used by self-builders who are building with straw. Bjørn references the recent International Passivhaus Conference where the dangers of high water absorption in lime render were discussed. At Createrra they are looking into other options, such as industrial certified render plastered on wood fibre board which creates a thinner layer.

There is Often a Trade-Off When Using Natural Materials

Bjørn explains the difficulty of trying to get the right balance between using natural materials and materials that will last well under humid conditions. He sees this situation persisting for the foreseeable future, though predicting huge development and innovation in this area.

Natural Materials are the Basis of Innovative Products

Bjørn uses the example of a Swiss company who have experimented with using enzymes to treat the straw, thus giving it very different properties once it has dried out.

He also explains how a Danish company are using crushed mussel shells to make a foundation. The shells don’t absorb water and with air gaps they do have some insulating properties.

Much More Experimentation is Required for Natural Foundations

Bjørn feels they are still some way off an ideal natural foundation that he would recommend for clients. Hempcrete is another example he gives which, while appropriate for some areas, doesn’t have particularly good insulation values so wouldn’t create a thermally efficient building.

Airtightness is Crucial and Has Often Been Overlooked by Self-Builders

Problems are caused by humid air going through gaps in the construction and condensing in the structure.

One solution is to use a clay plaster, which is airtight, however it is difficult to achieve full airtightness because the plaster will always need to connect somewhere, such as where there are electrical sockets or beams going into walls.

Createrra are helping to develop a system using Ecococon straw panels where the airtight layer is on the outside of the straw insulation. This is in contrast to the typical way of doing things, where the airtight layer should always be on the inside in cold climates. These panels are wrapped in a recyclable airtight membrane and covered with wood fibre panels / ventilated façade. Early blower door tests have found that they meet the rigorous Passivhaus Standard.

The Ecococon panels are a combination of straw with wooden construction which are used to create the structure.

It is Difficult to Achieve an Entirely Natural Building

There are areas where construction using natural materials can be achieved easily, but areas like the foundations are more challenging. When also considering the whole of the interior, things like electrical cables being wrapped in PVC shows where there is still so much more that can be done.

Bjørn says that only around 500 materials were used in the construction of buildings at the beginning of the 20^th century, but now that figure is closer to 50,000. He sees the goal of having a building that at the end of its life can be put on the compost heap or recycled as being a greater challenge than solving the world’s energy crisis.

Createrra Have Completed 5 Passivhauses Almost Entirely From Natural Materials

The exceptions were the foundations and some of the roof membranes.

Feedback from their customers has been extremely positive, with perfect comfort levels maintained throughout the seasons. Bjørn thinks when people see the flat straw panels and the efficiency of the construction they see it as an attractive proposition, when perhaps they might not previously have considered straw.

Find Out More

Follow Bjørn Kierulf on Twitter

Transcript

Download a transcript of the interview with Bjørn Kierulf.

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May 9, 2015
HPH078 : Externally Insulating a Bungalow with Straw Bales – with John Butler
John Butler tells the story of how he retrofitted a bungalow to be more energy efficient. Having carried out a lot of the work himself, he also shares what he’s learnt about airtightness and overheating.

Interview with John Butler

Although it had been John and Anna’s dream to build their own house, they found themselves muscled out of the local market for plots by builders.

John had attended a straw bale building course and was struck by some of the slides which showed a bungalow in the Czech Republic which had been wrapped in straw bales on the outside. With plenty of bungalows in the local area with poor energy efficiency their focus shifted away from the idea of building from scratch and instead towards searching for a property to retrofit and extend.

Straw was Always Part of the Plan, Whether for a New Build or a Retrofit

Having been on straw bale building courses and volunteering on builds, John felt that straw was a fun material and enjoyed the atmosphere on site from the types of people it also attracted. The more involved he got the more he realised its sustainability potential; being well insulating, breathable, accessible and a waste product from agriculture.

Gaps Need to be Eliminated Between the Bales and the Original Walls When Wrapping the Building Externally

Firstly the walls were levelled with clay to ensure no rodents or insects were able to crawl through the channels. Gaps would also potentially allow air flows which would bypass the insulation. Once the walls were level they were able to create a firm connection for clamping the bales onto.

Foundations Were Needed for the Bale Walls

As John was trying to avoid using concrete foundations they dug down and used gravel, compacting a layer, before adding further layers by the same method and finally finishing up with a strip of limecrete. The bales themselves were elevated from the ground by an insulated plinth brick wall to ensure that any moisture or leaks would run through the bales and drain out through the foundations.

Airtightness Should be Planned From the Beginning

Unfortunately airtightness was something John only became aware of later in his project! He discovered the importance of airtightness for energy efficiency through following others on social media, and then tried to incorporate it into the build. It was easier to do this in the extension, but in the bungalow they also managed to use tapes around the windows and are hoping that the plaster skim will keep it airtight. An air test they carried out before completing the finishes showed the weak areas and where they needed to go back and make adjustments.

John admits that with hindsight he would have planned better and carried out more research before starting, to ensure he had a really good airtightness system. He notes though that he would be interested in finding out about the sustainability credentials of the tapes and membranes themselves.

Initial Plans Were Designed and Drawn in Sketchup

Once John and Anna had thought about the spaces they were looking for in their new home, John drew their ideas in Sketchup before sending them to their consultant in the Czech Republic for suggestions.

A Vaulted Ceiling in the Living Area Helped Compensate for the Loss of Height From Insulating the Original Floor Slab

One option would have been to excavate the original concrete slab, however with the waste materials being sent to landfill and the risks of excavating within an existing building, it probably would have been wise to have knocked the bungalow down.

Instead, the chosen option was to use wood fibre insulation boards on top. This does mean however that they’ve not managed to get enough insulation in the floor, without digging the concrete slab out, for it to reach Passivhaus standard.

Solar Tubes and Roof Lights Provide Welcome Additional Light, But Have Their Drawbacks

The solar tubes have been effective in providing additional light without structurally taking up much roof space. In summer however, they have found that the direct sunlight beaming through their various roof lights has resulted in overheating of the spaces. This is something they had prepared for on the living room’s two large roof lights and installed external shading, however this does mean that using the shutters blocks the light from coming in.

Again, with hindsight John would have planned for this and used the PHPP (Passive House Planning Package). It is an annoyance for John that they had planned for saving energy and not being cold in the winter, but now have the opposite problem of overheating in the summer.

Self Building Has Been Satisfying But Draining

While John finds it very satisfying to point at the work he has done himself, he readily admits that it has also been all encompassing and draining. He recommends having people to help out at least with elements of the build to provide stimulation and motivation.

He sees self building as a balancing act, of paying people to do the labour meaning you could get back to work earlier, against the potential financial savings and satisfaction of doing the work himself.

The result is a house where he and Anna are enjoying their new light, warm and comfortable spaces.

Find Out More

Visit John Butler’s blog on his self build

Follow John Butler on Twitter

Transcript

Download a transcript of the interview with John Butler.

The Future of Housing – Premiere!

The date is set for the first screening of our documentary The Future of Housing – And How Airtightness Can Help.

This project was crowdfunded on kickstarter earlier in the year and on Thursday 4th December 2014 you can see what we’ve been up to!

The venue will be the Mildmay Community Centre, which was the UK’s first non-domestic retrofit to the Passivhaus standard. So there’s a building to check out too!

We hope you are able to join us for what will be a special evening. Capacity is limited, so get your ticket now.

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November 12, 2014
HPH057 : Low Impact Living Affordable Community (LILAC) – with Joe Atkinson

Joe Atkinson explains how the LILAC cohousing community came together and why their project is affordable for everyone.

Interview with Joe Atkinson

Around 2005, Joe got quite interested in fuel depletion and climate change. At the time, Joe had a nice job in IT and was getting paid well but felt that his life wasn’t very fulfilling. He was looking to get involved in something that would provide this fulfillment, and be in line with his ethics.

Eco-building Can be Really Simple

Joe did a Masters in Architecture at the Centre for Alternative Technology in Wales, at Machynlleth which he found absolutely fascinating. Being a bit of a techie, he really liked the technical side of the course and the physics behind how buildings work. This got him really interested in eco-building and he feels that a lot of it is actually really simple and backed by common sense. Instead of constructing thermally leaky buildings, we should be building sensibly.

How Joe Got Involved in LILAC

Joe went to an event where some of the members of LILAC (it was previously known as Leeds Eco Village) had a stall and were trying to recruit new members. Joe was at a point in his life where he was looking for somewhere to live. LILAC appealed to him as it was community of people who were building eco-houses that he would be able to afford. It was a no-brainer for him from that perspective and he got involved.

Being on the Board

When Joe joined, the group was really keen to recruit people on to the board. As Joe is the kind of person who commits totally to something new that he gets excited about, he decided to join the board.

Being on the board meant taking legal and financial responsibility for the project collectively with the other board members. Once Joe joined, he found his own little niche as the person who is a good team-builder. The board at the time was populated by lots of people who were really dynamic and making stuff happen, and his supportive role on the board really helped things along and played to his strengths.

Making Community Decisions

The board needed to think about how the whole community functioned and to avoid a two tier decision making system between the board and non-board members of the community. To address this concern they had an away weekend where an external facilitator came in and they did a whole community visioning and strategic planning exercise. They discussed the whole community’s goals and looked at different options for how to get there. Smaller task teams were set up to look at particular aspects of the project such as their relationship with the existing community, recruiting members, publicity and so on.

Joe joined the group that was to liaise with the professional team- the quantity surveyor, the project manager and the main contractor. The group went through a tender process to appoint a contractor.

Developing a Relationship with Leeds City Council and the Existing Community

The group had been in discussions with the Asset Management Team at Leeds City Council about various sites around the city and looked at two that were very suitable. It took the group a while to develop a relationship with the Council because when they first approached them, they probably came across as a bit of a rag-tag bunch of optimistic, well-meaning do-gooders who wanted to build some eco-topia. It wasn’t until they came back to them with a project manager and a serious business plan that the Council started to really take them seriously as a credible group who they could sell the land to.

They ended up choosing the site in Bramley, where they did a community consultation with the local residents. The community really liked the idea of what they were trying to do which gave the group a really good feeling about choosing that site.

LILAC- (L)ow (I)mpact (L)iving, (A)ffordable, (C)ommunity

LILAC is an acronym and stands for three main elements- Low Impact Living, Affordable and Community. The Low Impact Living element comprises of buildings built using the fabric first approach, an airtight construction with mechanical ventilation with heat recovery and the use of renewable materials such as timber, straw bale, lime render and lime plaster and triple-glazed windows. There is solar PV on the roof and solar thermal for the houses but not for the flats. They have used the Passivhaus approach, and are not far off from it, but haven’t spent the extra money to get the accreditation. They also have fewer car parking spaces- there is half a car parking space per home and two secure bike parking spaces. They have also set up community agreements for lots of other different aspects like sub-letting agreements, the car policy and the installation of electric car charging points.

The LILAC Mutual Home Ownership Society

Joe explains how the affordability model of LILAC is achieved through their legal and financial structure which is called The Mutual Home Ownership Society. It is essentially a housing co-operative and it uses a new financing model unique to Britain, as each member is effectively buying shares in LILAC Mutual Home Ownership Society Limited.

The total project cost is divided proportionally between each of the twenty homes, with each home representing the notional build cost for each unit, e.g. where the four bedroom units are more expensive to build than the three, two and one bedroom units. The amount that people pay to live there is related to their earnings. So all the members pay thirty five percent of their net income and the amount that relates to determines the exact size of their home size.

Once the debt associated with your flat or house has been paid off, you drop down to just paying ten percent of your net income. At that point you’re just paying a small amount as a service charge or ground rent. If you had a normal leasehold, you’d always be paying a small amount for things like insurance and management fees, etc.

The group is decoupling the value of the homes from the housing market, and that’s intended to keep these homes affordable in perpetuity. So they will always have the same ratio to earnings. Living at LILAC isn’t about investing in property; it’s about creating affordable housing as a legacy of the project and about buying the service of a home. It’s about homes as shelter, not as a nest egg or an investment.

LILAC is about Creating Good Quality Affordable Housing

According to Joe the process has worked so far and they are keen to support other groups who are interested in this model. At LILAC, they are not creating social housing, but affordable good quality housing. Joe can’t imagine anywhere else where you can get to live in an eco-house with all this amazing community and it’s affordable and you get to own it. This is potentially a model for anyone who is excluded from home ownership for whatever reason.

They have an active waiting list and they are receiving new applications all the time. This gives the current members an added level of security. If a member were to lose their job and couldn’t afford to live there anymore, there’s a whole process that takes place before they have to move out. And if at the end of that process they still have to move out, there is a waiting list of people that already want to buy your shares and move in.

Membership by Consensus

Everyone who lives at LILAC- apart from a couple of the very early founders – has had to apply to join. Because the group operates a consensus decision making model, everyone in LILAC has the right to veto someone applying. When Joe’s partner moved in, she had to write an application too and there was a period when somebody could’ve voted against her moving in. She sailed through with flying colours, recounts Joe happily.

Living in Cohousing Comes with its Own Challenges

Joe feels that it has been quite interesting going through a process where you have to prove that you can afford to live at LILAC because the affordability model relies on everyone declaring their financial situation. Although they now have a finance task team who look at all the finances, previously applicants had to submit their application with their financial information to their future neighbours which could be quite uncomfortable.

Living in an intensive cohousing community requires you to adapt and change the way you think. It can be really nice and sociable, but at times overwhelming. One of the real strengths of the cohousing design is that you have got your own place and you can retreat to it if you need to. But when you’re ready to come out, you’ve got a whole community there waiting.

Everyone at LILAC has been very supportive and open minded and have a real willingness to learn about living in a community and to learn about themselves as well. Living in cohousing challenges you in ways that you might not expect- it is a bit different to living in a traditional street in Britain. Joe admits that there have been a lot of challenges so far and there are likely to be more in the future, but they look forward to them.

Find Out More

LILAC’s website

Transcript

Download a transcript of the interview with Joe Atkinson.

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June 11, 2014
HPH022 : Why Build a House with Straw Bales? – with Mark Saich from Green Building Solutions
Mark Saich from Green Building Solutions gives an insight into why straw bale building is becoming popular. He also addresses some of the issues that we may harbour around the safety and durability of this low impact and low carbon material.

Interview with Mark Saich

Mark has worked in construction for about 25 years as a carpenter (joiner), in building control and also environmental health. Concerned about how buildings were being built, the amount of waste, the embodied energy of the materials in use, etc., he began to explore other options. Since 2000, he has been straw bale building and running training courses in the South East of England.

Straw Bale Building is Nothing New

Straw bale building was used extensively in Nebraska, US, in the late 1800s and early 1900s. Early settlers had to make use of the materials they had to hand.

The Quality of the Bale is Paramount

Although the bales used for construction are essentially regular bales (that you would see in a farmer’s field), they must be of good quality. This means the bales must be nice and tight, reasonably even-sized, dry, vermin-free and seed-free, etc.

Avoid Damp and Dark Bales

To a degree, choosing the right bales is a common sense undertaking. If a bale is damp it will smell damp and it will probably look darker and might even be blackening. These damp bales will also be heavier than a usual bale. Obviously experience of a dry bale is important to be able to tell this. Asking sensible questions of the farmer will also be helpful but it may still be a good idea to engage the services of someone who is experienced in straw bale construction.

A Low Impact Foundation May be Possible

Mark explains that for a load-bearing structure (essentially when you build out of bales just as you would if you were building with bricks) there may be an opportunity to lay a low impact foundation with less concrete, but this will depend on the ground conditions and the size and design of the building.

Problems Generally Only Arise When the Basics are Not Achieved

Although Mark has seen examples of black mould and mushrooms growing on unfinished buildings, he says that it comes down to inappropriate detailing and weather protection during the build. A lot of the principles that need addressing during a straw bale build are the same as a when constructing with brick and block, timber, rammed earth, etc. Get it off the ground and stop rising damp coming up into the building (with the damp proof course, etc.).

Moisture is the Biggest Threat to a Straw Bale Building

As with any building, dealing with moisture is very important. Essentially in a straw bale building the damp proof course is protecting the timber ladder as much as anything. The other source of (external) moisture is rain, which is kept out by having either impermeable or semi-impermeable materials. While in a brick house this would be the bricks and mortar, in a straw bale house it might be timber cladding or lime render.

Internally, a good ventilation strategy will be necessary to deal with moisture that builds up in the air from cooking food or drying clothes, etc. Using breathable materials – that have the ability to absorb and release moisture without it adversely affecting the longevity of the given material – can also assist in this process. Some examples of breathable materials include timber, sheep’s wool, wood fibre, lime plaster and straw bales.

Straw Bales are Excellent Insulators

Although the type of straw, its density and the quality of the build are all factors that affect the rate of heat loss, on average straw bales have a U value of 0.15 w/m². Put into context, UK building regulations currently only demand 0.28 w/m²(so a straw bale wall has roughly half the heat loss of a building regs compliant wall).

Bales Also Used to Form Prefabricated Panels

Mark talks about the ModCell system called Balehaus, which claims a U Value as low as 0.13 w/m²is possible for their 480mm straw product.

Expect a Wall Thickness of 0.5m

Typically with a rendered, plastered and clad (straw bale) wall, the thickness will be about half a metre. However, with building regulations likely to become more stringent in the coming years and most ultra low energy buildings demanding a lot of insulation anyway, this space is not out of the ordinary. Unless in a densely populated area, sacrificing an extra 10cm or so (in thickness) to use a low embodied material is not normally a big issue.

Load Bearing Structures Rarely Reach Three Storeys

Mark talks about non-load bearing structures – essentially where there’s a framed building with straw bales in between – and how with an engineered frame (that’s been tested accordingly) and infill panels, there is no limit to the number of floors of a building. With a load bearing structure, on the whole they are only single or double storey buildings. Mark says there are some examples with three storeys but it’s more like a half storey with a low eave (a chalet bungalow), that reduces some of the risk and some of the heights of the straw. This also makes better use of the materials because you are occupying half a roof space.

If a Building is Structurally Sound, Resale Should Not be a Problem

Although Mark had no information on whether straw bale houses can be valued alongside brick and block houses, he suggested that most people are fulfilling a dream to live this way and might stay in their new homes for many years. However, if a house is structurally sound and the building has been approved, inspected and signed off by building control, then getting a mortgage shouldn’t be a problem. Some mortgage companies will insist on a building warranty (which can be obtained from warranty companies). In the UK, Triodos and the Ecology Building Society both lend money at a preferential rate if you build to a good eco standard.

Building a Straw Bale Home has the Potential to be Cheaper

Trying to make a house ‘eco’ as an afterthought, by transposing materials for example, will probably mean that a straw bale build becomes more expensive. Designing the building from scratch with good environmental considerations can help bring the price down, particularly if you’re making your own clay plaster or if you use reclaimed materials, etc.

The Cost of Walls is Approximately 15% of The Build

As the walls only account for about 15% of the final cost of building a house, the savings of a straw bale construction may not be as great as one might hope. So, comparing like-for-like brick and block house to a straw bale house, even if the straw bales were half the price, it’s not a massive reduction in the cost of the build.

The Simple Things Will Lead to a Home That is Cheaper to Run

Mark points out that designing a house to the size of your needs rather than to that of your greed will really reduce costs. Also, having a good thermal performance in the floor and the roof, and high performance windows that benefit from solar gain. Plus, installing high efficiency heating, lighting and hot water systems will all contribute to lowering the running costs.

Constructing with Straw Bales Lends Itself to a DIY Build

Mark sums up building with straw bales as friendly and fun, and it ticks all the environmental boxes! He does recommend that it should be guided DIY, whereby you engage the services of someone who understands how to design buildings with straw and ideally someone with practical experience, too . Neglecting this could be costly for the building both in energy terms and longevity.

Green Building Solutions

As well as consulting on ecological building, Mark runs training courses on bale building (as well as spoon carving, clay plastering, etc.)

Transcript

Download a transcript of the interview with Mark Saich.

Ask Your Questions or Share Your Feedback
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Ben’s Holiday Reading!

Ben talks about reading a short story on climate change during his holiday. It blends facts from the past with a possible outcome of the future and is written by a ‘historian’ in 2074. It’s less than 15 pages and is well worth reading.

The Collapse of Western Civilization: A View from the Future

By Naomi Oreskes and Erik M. Conway

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May 8, 2013