HPH139 : Building biology principles – with Tomas Gartner from Gale & Snowden
Architect Tomas Gartner explains the principles of building biology and how they can be applied in your self build.
Interview with Tomas Gartner
Tomas qualified as an architect in Germany before moving to the UK in 2007 where he started working for Gale & Snowden, a Devon based architecture practice specialising in low energy, ecological design. He became a BREEAM code assessor and took a Passivhaus course in 2009 at the time that Gale & Snowden were doing their first Passivhaus buildings in Exeter, before studying for a building biology course in Germany.
Building biology evolved in Germany in the 1960s
In the early 1960s, when construction activity picked up in Germany, industry responded with more highly processed, cheaper goods which could be installed more quickly and with shorter drying times. Up until that point they had typically been using traditional materials such as brick, concrete, glass and timber, but Tomas estimates that today, probably 90-95% of construction materials have a petrochemical content and are highly processed, with adhesives, additives, coatings and treatments.
So this led to the development of building biology, which aimed to establish whether there were associated health risks with any of these chemicals.
“So it’s not about you can’t use them but it’s more about if they are a health risk, is there an alternative that we can use, economically but also technically without compromising on the performance, which takes that risk out of the building.”
The building biology standard is not a certification standard
Instead it provides a 3 page report defining healthy levels of potential hazards in the indoor environment, such as pollutants, VOCs, CO2 levels, temperatures, surface temperatures, radiation, dust, particles and mould.
While Passivhaus will give you a good air quality compared to a naturally ventilated building, Tomas explains that it is fighting the symptoms because it doesn't actually look at the materials that are being used. A ventilation strategy can only reduce the concentration of pollutants in a building, but there will still be constant off-gassing which a resident could react to if they're particularly sensitive to certain chemicals.
“But what building biology is about is one step before that actually. It’s not looking at right, let’s put together a building, don’t care what it is because we have a ventilation system takes it away anyway. We take it one step before that: what materials are we using in the first place, minimise the emissions from these materials, potential risk to it before we then look at the ventilation strategy and get a ventilation strategy that is as good as possible.”
Building biology has a human focus and starts with an optimum environment, which they try and achieve in as energy efficient and economic way as possible. That will vary from client to client according to their needs and what feels comfortable to them. Then the architect can tailor the building to them.
With a Passivhaus, Tomas suggests that sometimes, rather than squeezing it down to 0.3 air changes, it can be better to go for 0.5, compromising on energy efficiency but providing better air quality.
“We want to come to a natural or as close to a natural undisturbed environment as possible.”
The World Health Organisation provide a list of potentially carcinogenic agents, with figures based on a range of studies, which include the magnetic fields from household electricity, high frequency radiation from mobile phones, DECT telephones and Wi-Fi. It isn't clear how radiation is linked to cancer but there seems to be an increased risk for certain types of cancer where people are exposed to higher rates of radiation. Building biology uses a precautionary principle. It doesn't seek to prove these things lead to cancer, but they attempt to minimise the risk and design it out where possible.
Tomas stresses that it's not about dictating what you can and can't have, but it's all about the exposure rate and trying to minimise it to a safe level, particularly in areas where we spend a lot of time, such as bedrooms. He explains that a mobile phone, even if switched off, will build up a connection every 30 seconds or so to check on connectivity, emails, etc. Tomas recommends that if you do need your phone in the bedroom that you switch it to Flight Mode, as this will not build up connections and is relatively safe.
Tomas questions whether you even need Wi-Fi enabled at night. If not, it can be on a timer to switch off automatically at a set time.
When it comes to wiring, they use a radial system which means every room has its own circuit so they don't get pollutants from any other room into that wiring system. They then create a distance from the bed space to potential appliances – even moving sockets half a metre away from the bed will be enough to drop down to reasonable levels immediately. Another suggestion is using shielded cables if within a lightweight construction, which can reduce the fields considerably.
Off-gassing / materials
Tomas acknowledges that it can be extremely hard to get all the information you need about materials, as it is not something suppliers will generally want to reveal. He uses the example of traditional paints which have 4 or 5 ingredients in them, compared with modern paints which contain over 150 substances, most of which are on the carcinogenic list of substances. Although the amounts are very small, they might be put on walls in multiple layers. Add to that the varnish treatments and fire retardants on floors, drying agents in paints, substances that make paints a little easier to apply, etc. These things generally don't benefit the end user, they just mean that the building can be handed over a bit quicker, but it is the end user who will be living with the off-gassing in the coming months and years.
With water quality in the UK being relatively good, what is important is maintaining that quality once it's within the building. Water quality within a house can be compromised by old lead pipes, old appliances and stagnant water sitting around in long pipe runs. Gale & Snowden start by making the connection to the drinking tap as short as possible and use a stainless steel connection because it's anti-bacterial. Then they design the rest of the water system depending on the softness of the water, the pH value, and use materials that don't get affected by it.
They wouldn't normally recommend water filtration because a filter is only effective if regularly maintained. Otherwise a residue builds up which can backflush into the system and provide ideal conditions for bacteria and mould to develop.
“And so the lower risk is actually not to have a water filter, have decent materials in there, design it in the way that where you get your drinking water from, you flush it regularly through that and have short connections to that point.”
Outside spaces are important for mental and physical health, and for social interaction. Building biology looks at urban design too, whether there are better forms of living that can be considered and how we can integrate with the landscape. It also has strong connections to permaculture principles. Where there aren't such opportunities it's still about creating a healthy living environment and trying to improve it wherever possible. If you're at the start of a project, that can include making use of opportunities to impact on regional planning and creating external spaces as well as healthy internal ones.
“And that starts with your energy grid. Bringing it back to radiation, where you have your mobile phone masts for example. How you supply energy and resources, water to the scheme, but also how these spaces that you create interact and how you create social spaces as well which support family living as well as elderly for every part and every member of our society, a holistic approach in that as well.”
It's not about being fanatical
Tomas is keen to stress that building biology is not about worrying people and being fanatical, but about taking a reasonable approach, understanding the risks and trying to improve wherever you can.
“You will be surprised how far you can get with very simple measures that have minimal impact on your lifestyle.”
Find out more
Visit the website of Gale and Snowden
Follow Gale and Snowden on Twitter
Download a transcript of the interview with Tomas Gartner.
The Hub update
Our case study, Long Barrow, is currently up to date with progress on site. If you listen to podcast episode 100 you'll hear Alex Baines giving an overview of progress to date and explaining why he chose to stop before running out of money. You can catch up on all the videos we have produced on the build so far, taking you through plot assessment, the dig, insulating the slab and why you'd do that, the concrete pour, basement walls, steel frame and all the ICF construction and the roof going on. And we'll pick this up again once construction work resumes.
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