On 05/12/2013 16:48, Fredxxx wrote: ...
The concern is about vermiculite from the Libby Mine in Montana, which also had a deposit of tremolite asbestos. About 70% of the vermiculite sold in the USA from 1919 to 1990 was supplied from that mine, mainly under the trade name Zonolite. Vermiculite supplied since 1990 is considered to be safe, as is any that did not come from the Libby mine before that.
Colin Bignell
I think these days it's mainly used to insulate round flue liners, having the obvious advantage that you just pour it down from the roof.
I use it a lot in the garden. Great soil improver
The last surveyor we had used a laptop and his program had drop-down options. If what you had was not on the drop-down then tough he could not enter it and did not feel inclined to add his own notes. In my case I had a combination of 100mm of Rockwell and 100mm of Celotex plus boards. All he could do was enter the physical thickness so it went in as 200mm of 'insulation' which assumed, in the calcs, to be as efficient as fibreglass and not the approximate effectiveness of
300mm. My complaints fell on deaf ears but one house viewer was so impressed he bought the house - I am sure there were other reasons too ;)Mike
snipped-for-privacy@btinternet.com posted
When I put this forward in my building plans the local authority building control people wouldn't accept it, on the grounds that different layers of materials with different insulation properties would cause condensation.
I guess if there was wool under celotex and no vapour barrier, you could get condensation on the underside of the celotex, and if wool gets wet it loses its insulation properties, but this would then be no worse than just the celotex. My BCO was OK with rockwool above celotex in a roof. In a loft with just wool, moisture can percolate through the wool and into the air above. Simon.
Yes, if you do this, the wool must be on the cold side, and the celotex on the warm side. Otherwise, you will eventually get condensation at the boundary. The more serious problem is that this will make any timber go rotten.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.