black mould and insulation

[honda]

hi, the main bedroom of my house has a large bay window. the wall underneath this window is plastered single leaf brick inside with battens outside and then tiled with rosemarys. several years ago, in an attempt to cut the heat loss from this wall, i lined it with foil backed plasterboard and then wallpapered and all was well. but now, due to the exeptional cold weather i suspect, the wall paper is damp and covered in black mould.
i have removed the wallpaper and the plasterboard and would now like to better insulate this wall but would like suggestions as to what to use and how to go about it as i have since learned that foil backed plasterboard is not an insulator. thanks.

 

[PrenticeBoyofDerry]

foilback boards help keep moisture out, but not a good insulator.
you could batten your internal wall out and install thermal boards, such as kingspan celotex and thermaline(you can get these with a vapour check barrier).
or maybe consider removing tiles and installing the insulation at that point.
This may help
http://www.insulation.kingspan.com/uk/pdf/tw55.pdf
but doesn't need to be kingspan.
http://www.british-gypsum.com/produ...s/gyproc_thermal/gyproc_thermaline_basic.aspx

 

[honda]

thanks for that prenticeboy. should have mentioned that there is a radiator on this wall so only have approx 3 cms between it and the wall so will need something thinner to insulate the wall.

 

[jm2000]

HI, you need to find the source of the damp. having a rad on the wall maybe dragging out the damp. is it tracking in under the window.

You could remove the tiles from the outside, insulate, tack on some visqueen or other dpm, replace tile baton and re-tile then silicone under the window.

 

[honda]

thanks jm2000, since my first post i have now confirmed that the problem is condensation. to remove the tiles,insulate and then replace the tiles is a warmer weather job i think, plus the fact i have a slipped disc at the moment which prevents any ladder climbing lol. however what both you and prenticeboy have suggested is the ideal solution.what i need at the moment is some insulation,if you can suggest something, which will fit behind the radiator as a stop-gap remedy. (excuse the pun)