Green Building Forum - Advice and sensible London-based contractor for internal insulation

Advice and sensible London-based contractor for internal insulation

DamonHD — Tue, 20 Jul 2010 14:17:38 +0100

No one going to warn me about a paint vapour layer over my new skimmed plaster causing it to crumble and trapping moisture between it an the outer membrane?

Go on, tell me I'm a bad/foolish boy?

Rgds

Damon

Advice and sensible London-based contractor for internal insulation

Saint — Tue, 20 Jul 2010 15:18:31 +0100

Damon, just double check as its not always visible behind the whiskery aerogel edge but see if there's a foil between the plasterboard and the aerogel.
Unless you specifically asked for no foil it normally comes as standard on Spacetherm (aerogel Space Loft) laminates

Advice and sensible London-based contractor for internal insulation

DamonHD — Tue, 20 Jul 2010 16:07:28 +0100

Fab! Thanks! Yes, I looked at an off-cut and there indeed is the foil.

So I guess that it will be my vapour barrier, well to the warm side, and all is well?

Rgds

Damon

Advice and sensible London-based contractor for internal insulation

DamonHD — Tue, 20 Jul 2010 16:14:03 +0100

Though I note that we did not vapour tape at the front of the boards before plastering (because I assumed them to be vapour permeable), so there's a moisture route through the skim into the gap between boards so an impermeable base coat may still be a good idea, else we have to gouge out the plaster and reseal there.

Bv<

Rgds

Damon

Advice and sensible London-based contractor for internal insulation

Saint — Tue, 20 Jul 2010 18:59:54 +0100

Damon, had a feeling there'd be a foil in there somewhere
Gyproc drywall topcoat used to be the recommendation as a vapour check. 2 coats did it. Googled it and came up with this llink
http://www.wondertex.co.uk/CrossProductPages/Wondertex-drywall-topcoat.asp

Advice and sensible London-based contractor for internal insulation

DamonHD — Tue, 20 Jul 2010 19:42:25 +0100

Ah, fab again!

OK, I've asked the builder if we can do that. Much better than any gouging.

Rgds

Damon