In the last post, we figured out the correct height and angle for the new roof, in preparation for the roof beams. This post explains more about the many layers in an eco-roof, as well as more problems we encountered.
These Steico beams aren’t easy to fit at all. After discussions with the architect it took ages for the builders to measure and discuss fixings, and then measure again. This has to be exact. There is a lot of thinking ahead on this build. The placing of the fixings are crucial – it is astonishing how much power there is in a gust of wind, and a gust of wind could take the roof off if we get it wrong.
These beams will eventually form the area for the warmcell insulation to be blown into. They will also be the main structure of the roof that everything else will fit around. This means the roof is taking ages to make, requiring a lot attention to detail. All the Stecco Beams have to have the gaps where they intersect filled in with small bits of wood.
Coping with bad weather during a build
We ran into a patch of bad weather. It rained on and off for days just when the builders were working outside and the roof was off. They tried to keep going with building the new eco-roof, but driving rain made it impossible. It was so frustrating to see everything have to stop again and my house with no roof, eco or otherwise, but instead covered in plastic sheeting while we waited for the weather to improve.
In middle of all this, the Gutex boards arrived. These are an important layer in the eco-roof. They are made of woodfibre, and were going to be screwed onto the Stecco beams over the whole of the roof. I was worried the rain would make the wood fibre damp and ruin it. However, they had been treated, so were fine to be left exposed for up to 3 months. In the end, the boards were only out in the open for about three weeks because the builders managed to work in between bouts of rain. Their commitment meant there was plenty of time to get the boards screwed onto the roof and covered over.
Importance of Gutex Boards
The Gutex boards form the outer layer of insulation for the roof. They are flat solid boards made of wood fibre, and dovetail together all round the sides with tongue and grove joints. This means that if you push them close together when nailing them to the roof the join will be almost airtight. Having said that, we still needed to tape up all the joins with special tape, to make sure we didn’t have any gaps at all. But before that, the sheets of Gutex are screwed together with special screws, much longer than normal screws. There are two lots of fixings: one sort goes in at an angle of 60 degrees and the second at an angle of 90 degrees.
You need a good builder for an eco-roof renovation!
I go to meetings with the builders to sort out these things, and am amazed how complicated and detailed this is. I am so pleased that the builders know what is going on! They are all so interested and committed to making it work – which is exactly what you need on a build of this sort.
We are using a variety of special tapes in different parts of this build, to tape up different types of materials. It is very important to do this properly when building an eco-roof: the more attention to detail the more airtight your building will be. With an old building, you have a built-in disadvantage – you have to deal with what is already there. More often than not (as we have found) this is not straightforward and surprises appear when you strip out the building. If this was a new build it would be far more straightforward!
That’s it for today. I hope you enjoyed this post and next time I will tell you about tiling the roof and adding solar panels – a really exciting step. Be sure to come back and join me on the next post.
CotswoldEcoBuild 