Cavity Wall Insulation

patrick j wrote on 26/03/2005 :

I don't know, so I can't help you on that point. I can say that we had it installed about eight years ago and that we have no damp problems. The house is a semi, built on a concrete raft style of foundation. It was installed by drilling small holes at 1m or distance then blown in.

The heat is transmitted across the cavity by the air within the cavity circulating and carrying the heat from the inside wall across to the outer one. Better than air would be a vacuum, but obviously this is impossible to achieve. The idea of the insulation is to prevent the circulation of air, without itself conducting heat.

It seems so far as we are concerned, to have been a worthwhile investment. The house has fewer cold spots and has been noticeably warmer even near the walls during coldest weather.

Adding cavity insulation requires building control consent and they will have lots of experience of the types of property in your area and which sorts of insulation, if any, can successfully be installed. I'd give them a ring.

I would suggest asking several possible suppliers for inspections/quotes. You should be advised if your property is not suitable.

I once had a prewar bungalow where a supplier refused to fill the cavity - possible because the DPC was slate.

Nowadays there are subsidies whcih make cavity wall insultation very cheap.

I was talking to a chap ( not an expert ) about cavity wall insulation a while back and asked him whether it bridged the cavity, as regards damp, and he said no. I think rockwool has no natural capacity to 'wick' damp so that must be the explanation. He was singing the praises of cavity wall insulation anyway, said he heating bills dropped quite a bit. I have a neighbour who gripes about their cavity insulation though, they had polystyrene balls injected into their caity walls, but reckoned every time there's a strong wind these things mysteriously appear from under skirting boards etc.

I received a letter some time ago about grants being available for wall insulation, try this website: wwww.heatproject.co.uk

Andy.

We have polystyrene ball cavity filling, it was put in when the house was built 10 years ago. We've never had a problem with polystyrene balls appearing.

Furthermore, when I drilled a core to take a tumble dryer extracta (4in diameter) I did get a few polystyrene balls come away, however for the most part these polystyrene balls gave the appearance of being loosely glued together. It's possible that once the builders squirted the polystyrene balls into the cavity some sort of liquid material was added at the top and it seeped down to goo the balls together?

Maybe your neighbour hasn't had this "glue" applied, if there is such a thing.

Andrew

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Serves him right for getting the job done by J Beadle (Builders).

Owain

Sounds like there' s no glue been added. Polystyrene balls and air is almost an explosive mixture. Gulp !!!