Thursday, 14 November 2013

The Use of Traditional Materials in Contemporary Architecture

Guest blogger Louise Thomas

On the 18th October 2013, the Norfolk Association of Architects held a conference on the Use of traditional materials in contemporary architecture. This conference, held at the Kings Centre in Norwich, consisted of five different talks about a range of topics. Not only this, but sponsors of the event also had stalls located around the room ready for the visitors to converge on during the coffee break halfway through the day.

The first talk, by Rob McLeod, was titled 'Another hot Summer – do materials matter? The performance of low energy buildings in a rapidly changing climate'. Although one of the more interesting talks of the conference, it was full of graphs, facts and figures about the problems of overheating in buildings with the imminent climate change.

According to the figures given, due to the modern insistence on low U-Values, buildings are no longer able to lose heat once its been gained, thus producing inside temperatures of 30ºC +. The World Health Organisation stated that 25ºC was the maximum that was acceptable. As can be shown from the figures, our houses and rooms are becoming warmer and warmer. So, what can be done about it? There are passive and active solutions architecturally, we can produce more accurate models and future scenarios, allowing a better understanding of what is happening.

However, it is only the architectural solutions that were interesting to me. It was no surprise that one solution to the problem was to design the buildings to deal with the rising temperatures themselves, rather than attempting to make it as warm as possible. Firstly, ventilation. It can help so much to just have a change in air temperatures flowing through the building/room/construction. Use windows that can open fully, rather than those that can only open 10cm. Allow for these problems to occur and design with them in mind. Second solution: Shading. Admittedly, this can be a little bit harder to design for as the sun likes to move around us, causing all sorts of problems - and by problems, I mean the height of the sun. In the winter, the sun sits low in the sky, and makes many forms of shading useless, as they are normally designed for the summer sun which sits high in the sky.

Mr McLeod went on to talk about whether Passivhaus was actually better than other construction forms, coming to the conclusion that, yes, they were but only marginally. Also, surprise surprise, he also stated that smaller windows meant that buildings were not overheating as much. It's not like the heat could get inside the building easier that way at all. So, what did I learn? That architects are getting too obsessed with loss of energy from the buildings, and do not see the problems that can be caused. If they only stopped to think about what the house would have to go through, climatically, then i'm sure they would look to the solutions mentioned above.

The second speaker, Ben Humphries, gave a talk called 'A modern take on thatch – The Enterprise Centre, University of East Anglia'. This talk reminded me very much of my lectures as an architecture undergraduate, as it focussed mainly on the design process. I'll admit, it was quite interesting, however he went so quickly through the slides it was very difficult to remember what materials were used at what point of the project.

Of the information that I did manage to get, it was emphasised that the project was designed using local materials from a 100 mile radius from the site. A good idea, and they managed to find lots of different materials to use that would create an interesting building. The brief of the project included to achieve Passivhaus certification, Breeam outstanding, be a 'Carbon Sink' and have a 100 year design life. They achieved all this and more.

They managed to achieve, early on in the design process, a value of 168km CO/m² for embodied carbon. Given that M4i gave the benchmark value as 500kg while Atking stated it as 845kg-925kg CO/m², this is an amazingly good value – and theirs was for a 100 year design life while the others it was measured against were for 0 year. Brilliant. When they came to finally show us the finished design, with all materials given and taken into account when calculating the embodied carbon amount, it came to 440kg CO/m². Which, if you had been reading correctly, was still lower than the benchmarks!

So did I learn anything about creating a low energy building? No, not really. But I did listen to a really good case study that can be studied to gather ideas.

The third talk, 'Natural building materials: The story of a straw bale house' was given by Jim Carfrae. Once again, this talk was quite similar to a case study, as the speaker was giving us a virtual tour of his own house when it was being built.

They used straw as insulation and used it as a thermal bridging barrier. The windows would sit in plywood boxes, the whole house was vapour permeable but the differences between the interior and outside meant that no vapour that entered the walls actually came out the other side of the straw bale. What was interesting is that he used a small sun lounge of sorts, to create natural ventilation by leaving part of the wall open at the beams. Apparently there was no heat lost through these gaps in the winter and it kept the rooms nice and cool during the summer.

A calculation showing the difference between using straw bale rather than phenolic foam shows us that despite needing a lot more straw than foam, the differences in something (again, he went too quick to find out what) turned out in favour of using straw. In fact, it was 30 times better! So again, I didn't really find out anything, and I was losing interest at this point, but at least I now know to use straw instead of foam.

At this point, we had a coffee break, and everyone converged on the stalls to find out what they were selling and giving out. I grabbed some booklets, talked to a couple of people and then went outside to grab myself a spare chocolate biscuit to have on the train home. Sadly, all good things must come to an end and the final two talks started.

The next talk 'shaping a context that allows earth into contemporary architecture', by Rowland Keable. This was the talk that I thought was going to be the most interesting but it sadly turned out to be the most boring and slowest talk of the entire day.

The talk was all about how he has done some work in Africa, to help them get guidelines down for using rammed earth as a building material. Nothing overly useful about how we can use rammed earth in the UK to our own use. Sadly, this was the extent of the talk, other than the quote “When you give up control on site, you give up a certain amount of control” - Well yes, of course you do. I think this sums up the speaker in its entirety.

The final speaker was, in fact, the most interesting. Ron Beattie talking on 'A step change in building innovation'. This talk was all about a new way of building a house/building so that there were no insulation gaps. Very interesting.

Admittedly, I couldn't quite figure out how there was no thermal bridging, as they must put the cladding on the structure in some way. But, yes I will admit that their method of building a house so that there was a continuous insulation seal was pretty innovative. They also wanted to create houses, or even any other building as they mentioned that they wanted to build for any use, that would be fireproof, soundproof to 65dB and such.

The delivery of the talk was very informative, he gave us lots of fact and figures and talked us through a 3D computer version of the construction. Students would be making the structural form, helping them with gaining skills. So in the end, I didn't learn so much about how I could alter a design to be more energy efficient, but I was given a whole construction method that did just that for me.

All in all, this was the end of the day. Questions were asked and answered, and I made my way home. A mix of thoughts were going through my head, and by the time my train got back to Cambridge, I had forgotten about most of what had gone on and could barely remember anything other than someone having 166+ 'um's and 'er's and that the last speaker was the most interesting. For anyone interested in green architecture, there was very little to help you design better yourself, but plenty to gain an understanding of what is going on in the world.

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