Archive for September, 2013

EPS, XPS or PIR for EWI?

I’m having second thoughts about using Polyisocyanurate (PIR) boards for our external wall insulation (EWI). PIR is the best commonly available insulator, so it will enable us to get the most insulation into the limited thickness that we have available. Unfortunately, I’ve just learned that PIR has some problems that may cause it to deteriorate with age. Firstly, it is liable to shrinkage, which means that gaps might open up between the boards. Not only would that compromise thre insulation, but it might show through the render, and spoil the external appearance of our house. Worse, PIR can deteriorate if it gets damp, which is something that is hard to rule out. Finally, the gasses trapped in the foam could leak out over time, further degrading the material’s performance. Is that bound to happen? No. But it’s certainly got me considering alternatives… Read the rest of this entry »

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