Cavity Wall Insulation

[bethbilly]

in yesterday,s d record, read that edinburgh castle have used wool as insulation, as it,s natural,breathable and can allow moisture and dampness out. is this the way forward?!!! i live in a slightly smaller pile, (three bed semi!!) i can,t have conventional cavity wall insulation as as house is built of concrete blocks and steel strappings. Any thoughts AB,s ?

[The Builder]

Wool prices to the farmer are so low these days, it hardly pays them to bag it up and transport it. I guess that should make the cheaper competitive.
I've no idea of the cost, but its applications will be much the same as with mineral wool.
It's really just an alternative product. Mineral wool is still breathable, so I doubt if it's much different... except a lot nicer to handle.

[The Builder]

Oh dear ^^^ "should make it cheaper and competitive"

[buildersmate]

I think you will find that the issue with pre-cast concrete blocks is that you don't have a conventional cavity that can be filled with insulation. Although some pre-cast blocks do have an air-space in the middle, it is not one that one can drill into to fill with urethane-type foam. So this is not about the filling material, per se, it is about the type of construction.

The Building Research Establishment (BRE) is the sure place to go for (unbiased) advice on this, as there are many sorts of concrete blocks used in the UK between about 1920 and the 1970s.

Two possible ways to insulate such places that have no cavity is to clad an extra layer incorporating a gap that can be insulation-filled, either from the outside or the inside. Both will cause major amounts of disruption.