Cavity wall insulation?

milliebear00001

Hi there

House I'm trying to buy has had cavity wall insulation. Should I expect to get any paperwork for this (was done in last two years)? The vendor said they only went 'halfway up the wall' but didn't know why - is that normal? I have zero buildings knowledge and am wondering what exactly a 'cavity wall' is - I gather there is a gap between two layers! Are they fairly normal and do they have any associated probs when compared with solid brick walls? Noise/damp etc?

slummymummyof3

Cavity wall insulation usually comes with a 20-25 year guarantee which is transferable to new owners.

Cavity walls are now standard build and the newer ones will have been built complete with cavity wall insulation. Houses with cavity walls built around the 1980's and before will not have been built with insulation so where owners have had cavity wall insulation installed they have either rockwool or polystyrene balls injected in to them to act as extra insulation. This just involves holes being drilled in the walls and the insulation pumped in and then the small holes being filled in. There can occasionally be a problem with properties with cavity walls where the cavity has been bridged with mortar etc and this can result in damp penetration. Cavity wall insulation appears to cause a problem when too much insulation has been crammed in, but most properties benefit from the additional insulation.

milliebear00001

slummymummyof3 wrote: »

Cavity wall insulation usually comes with a 20-25 year guarantee which is transferable to new owners.

Cavity walls are now standard build and the newer ones will have been built complete with cavity wall insulation. Houses with cavity walls built around the 1980's and before will not have been built with insulation so where owners have had cavity wall insulation installed they have either rockwool or polystyrene balls injected in to them to act as extra insulation. This just involves holes being drilled in the walls and the insulation pumped in and then the small holes being filled in. There can occasionally be a problem with properties with cavity walls where the cavity has been bridged with mortar etc and this can result in damp penetration. Cavity wall insulation appears to cause a problem when too much insulation has been crammed in, but most properties benefit from the additional insulation.

Thank you - so would the need for ventilation explain why they only went part way up the wall? Vendor seems to think the insulation has made a big difference to the warmth of the house.

spirit

I've recently bought a 1979 built house with no previous insulation. I've had it done now though. they have given me paper work to go with it. Not only is the house warmer, it is also quieter. There is a busy-ish road nearby which I now can't hear.

Don't know why they would only have gone halfway with it in your case. Is it a standard construction? i.e. brick cavity or perhaps steel or wood instead? that might make a difference I guess. The house I sold is steel construction and the structural engineers advised against more loft or any cavity wall insulation (the house a few doors along tried cavity wall insulation but the internal walls started to bow :eek:)

27col

A quick Google of things like cavity wall would soon extend your "zero" building knowledge. They say that a little knowledge is a dangerous thing, but no knowledge is even more dangerous and an open invitation to get ripped off.

donmaico

27col wrote: »

A quick Google of things like cavity wall would soon extend your "zero" building knowledge. They say that a little knowledge is a dangerous thing, but no knowledge is even more dangerous and an open invitation to get ripped off.

trouble is there ius an awful lt of conflicting opinions by so called experts.This chap is a case in point - http://www.askjeff.co.uk/cavity.html

spirit

Then perhaps have a look at the energy savings trust website to get info.

Avanice

The presence of a 'Shell Chemical' cavity wall filling on a rain driven 1950's house wall will at the end of this year have cost me around £20-25,000 to resolve. It has soaked up water and passed it to the inner walls and a couple of handfuls of the stuff will hold 1/2 pint of water.
Damp Proof Courses were replaced years ago as this was thought to be the problem, pointing was done, soffits and roof re-built etc. The solution now is to drop the outer house walls and re-build without the cavity wall solid fill.
It is the solid fill, across the cavity, that is the problem, had there been an air gap behind the outer wall the moisture would not have reached the foam.
A 25 year waranty or guarentee in the terms of a house life is nothing. The material in my cavity was there for around 35 years before causing visible problems, Shell discovered the problems and closed the division that was using the foam and stopped making it before I got the problems. Unless you know different, there is no redress there.
Rather than cavity fill I would (and have) built a 3rd 'dry-wall' wall on the inner side of the inner brick wall and insulated that.

27col

donmaico wrote: »

trouble is there ius an awful lt of conflicting opinions by so called experts.This chap is a case in point - http://www.askjeff.co.uk/cavity.html

I was merely suggesting that the op should look up to find out what a cavity wall is, as she said that that she did not know. The efficacy of cavity wall insulation is another subject entirely. I personally have had it installed for over 30 years, without any problems whatever.

iamcornholio

milliebear00001 wrote: »

Should I expect to get any paperwork for this (was done in last two years)?

This type of work should be registered with the building control section at the council, who will have a record of any such notification. Your legal advisor should check these records as part of the conveyance

donmaico

27col wrote: »

I was merely suggesting that the op should look up to find out what a cavity wall is, as she said that that she did not know. The efficacy of cavity wall insulation is another subject entirely. I personally have had it installed for over 30 years, without any problems whatever.

it seems to me that people have had different experiences with it most good but some bad. I asked the buider who is replacing some of my wall ties for his advice as on CWI and its effect on wall ties .Basically he was dead against it statin g that he sold his last house one year after having CWI installed because of the increased dampness he found .H e made no mention of wall ties mind, just the fact the lack of ventilation between the two walls in his view , must of been a serious consideration with regards to the increased dampness.
I am inclined to think that ventilation in the form of airbricks and the small window vents, is an absolute must.