thoughts about timber frame insulation

[redtop]

Hia all.  Planning in place for a 3 bed timber frame with flat greeen roof.  Researching timber wall / insulation options considering we need to do as much of the work as possible ourselves.  The building is in Looe, cornwall and is only 500M or so from the sea so we can expect it to be a wet / damp (mizzle ? ) area.

 

Any views re this sort of build up for the walls? Note we are trying to achive EPC B'ish, no point in going much more as we are seriel window openers lol

 

[ProDave]

You don't give the thicknesses of the various layers. so hard to form an opinion.

 

That is very similar to our wall make up.  We had the OSB racking layer on the inside like you (lost count of how many people told us we had put the frame up inside out)  In our case we had 2 layers of OSB with staggered joints to give sufficient racking strength.

 

I ended up fitting Frametherm 35 earthwool in the 200mm thick frame for cost reasons.  We had the 100mm thick Pavatherm on the outside and rendered onto the Pavatherm.

 

We did the same on the roof with the 100mm Pavatherm over the rafters, then a breathable membrane (Protect VP400) counter battens, battens and tiles.

 

U values of all walls and roof about 0.14  Just about to passive house levels, and we expect an EPC A