On Sun, 25 Sep 2005 10:15:53 +0100, "r.p.mcmurphy"
wrote:

| wrote:
| As the price of heating has increased, I have started to think about
| Cavity wall insulation again.
| I have previously been put off the idea due I always thought that you
| needed the air gap to prevent damp,
| therefore filling the gap with rock wool may cause damp.
|
| Does any body have any ideas as to the problems that can occur ?
|
| As it does seem a no brainer as it will only cost about 200 pounds
| and this can be saved in one year.
|
| i'd recomend it. my 1950's semi was done 6 years ago and the difference it
| made to the heat retention of the house was very noticable.

What happens is that the inside skin of the wall gets warm, and when the
central heating switches off at night, the inside skin of the wall
radiates/convects heat back into the room. This works better with old
heavy breeze blocks than with the more modern lightwieght cement blocks.

--
Dave Fawthrop dave hyphenologist co uk
The London suicide bombers killed innocent commuters.
Animal rights terrorists and activists kill innocent patients.