hello could any one out there pass on some advice ref insulating the internal walls in my 1950's ex council house cornish unit. the house is very cold upstairs, I replaced the loft insulation and added extra last year although we do have night storage heaters which after getting the electric bill were soon turned off, so have been using stand alone heaters. I cut a hole in the bathroom wall to see if there was any insulation inside, along with some raqther large spiders there was a piece of 2" polystyrene going half way up the wall but nothing else. the original water/vapour barrier appears to be in good order. I have to replace the bathroom suite at some point so will combine the works together. Any help would be greatly appreciated. thanks.

You have my sympathy, as I lived in one of these for a time in the 70's (an MoD house) and it was without a doubt the coldest house I've ever lived in, anywhere.

The primary problem is air leakage through the structure, as the prefab post and slab walls are often not sealed at all, in any way shape or form. This leaves the cavity very draughty, with just the plasterboard inner skin as the effective insulation.............

I think that you would be much better off looking at fitting external wall insulation, but before doing so you'd need to determine just how structurally sound the building is. Mine was spalling concrete off the posts and window surrounds from internal reinforcement corrosion back in the 70's so you would want to be very sure that yours is OK before doing anything that might cover up damage or make later replacement of the walls more costly (as you know, the walls will need to be replaced at some point, as there is a long history of structural failure with this system).

Overall, fitting EWI would both insulate and seal the building, significantly improving its thermal qualities. Fitting internal insulation isn't going to help anywhere near as much, because of the air leakage problem through the walls.

<blockquote><cite>Posted By: SteamyTea</cite>I often think that airtighness is more important than insulation, but then it does depend on the temperatures and windspeeds, but down here it is relatively warm but very windy.</blockquote>

Very, very true for Cornish Unit houses! Mine was in a relatively sheltered location (the lower married patch in Helston) yet the wall slabs would actually rattle in the posts in high winds. You could hear the wind blowing through the cavity behind the plasterboard. Combined with Crittal windows and only an open fire and boiler (with no radiators) for heating made for a thoroughly unpleasant environment in cold weather. The only point in its favour was that the rent (inc rates) was only £2.50 a week..............

Possibly work to make each room (esp downstairs) individually as air-tight as possible and keep doors closed, so heat can't easily escape into parts of the house where it isn't needed and/or out entirely through lack of airtightness upstairs.

I have a similar problem with my (being drylined by degrees) wood-framed, tile-hung house, eg see: http://www.earth.org.uk/note-on-superinsulating-bedroom.html

Rgds

Damon

hI guys/girls, i've got my house insurance due in a couple of weeks for my cornish unit which has had the re-inforced concrete replaced with block and render and a new tile roof put on, have any of you got any contacts for insurace companies that might specialise in this type of building. Any thoughts would be much appreciated. Have to log off now so will check any replies later. Thanks