cavity wall insulation

[apeelhollybank]

We recently had cavity wall insulation installed under the grant scheme through our power suppliers. they used rockwool, but how do we know they did the job thouroughly? I fitted a vent for tumble drier last weekend and couldn't find any sign of insulation material in the cavity in that area, although 2 holes had been drilled within a metre of the hole. the company are coming to "rectify" the problem on wednesday, but we are not confident they did the whole job properly. who would we go to, to get a survey done?, is it worth doing that. AP

[Fred]

Hi,

Someone knocked on the door offering cavity wall insulation for £140.

I'm not sure whether the house (built mid-70s) has cavity wall insulation or not; how can I tell?

If I do need it, is £140 a good price and are some companies better to use than others?

I understand they inject something into the cavity but what do they use? Is it like that awful expanding foam that you can't clean off? What stops it rising up the wall and coming out of the top or through air bricks etc?

We have a meter box cut in the side of the wall. Is there a danger that the meter box will be flooded with foam?

Also the builders for some unknown reason decided to put the soil pipe and rising main in the cavity behind the bathroom wall. I don't know if I am worrying unnecessarily but if we ever needed to access the soil pipe or main, would it be possible if they were caked in foam?

Thanks in advance.

[David Hansen]

On Mon, 14 Apr 2008 17:39:33 GMT someone who may be Fred wrote this:-

They should check this first.

The first thing to check is whether you can get it free or cheaply

is a good starting point to check on this.

Whether £140 is a good deal or not partly depends on the number of exterior walls your house has and its height.

No. They usually use small cut fibres which are blown in.

Gravity. A little will probably escape from the top, but can be put back in for neatness.

They should check that all openings are sleeved before starting.

None at all if it is installed properly. Does it have gaping holes in the back?

The fibres can be moved to access things, though neither of those things should be in the cavity wall.

[apeelhollybank]

as was the case in the 70s/80s with loft insulation. CWI is an hard to detect product for the householder is there a agency too oversee the work and assess the performance of participating companies? AP

[Phil L]

They don't use foam anymore, it's dry fibreglass, treated with silicone to prevent water tracking across. The fibreglass is pelletised (into small balls) and blown in with compressed air...sometimes rockwool is used but the method is almost identical. It only rises up about 12 inches, but will fall down (via gravity) about 4 feet, and across about 2, once installed, it never moves again until you remove it manually

[Phil L]

CIGA are the body who issue the guarantees (cavity insulation guarantee agency) and they have a website, but they will probably tell you to wait until the installers have had a chance to rectify matters first

[Paul Matthews]

I think his concern is the door knockers were the insulation equivalent of an offer to tarmac a drive, and that they may drill a few holes, faff with a bit of gear and fill the holes having done nothing in reality.

[Rod]

Of course they were. No reputable company knocks on doors like that to drum up business. (Yards from where I live is a no-doorstep-selling zone

- the need for these emphasises the nature of most doorstep sellers.)

[Fred]

Exactly so. I cannot see inside the walls so I don't know if I've got it already and if I have it done, how can I tell that they have done it properly and completely?

The company was KHI. I only know this from their ID badges; I have had no other documentation from them. This worried me; I was expecting a card or a brochure or something. Google says they are based in Nottingham. I have found one good review online and one bad one.

A chap called today and drilled just one hole. He did not have anything as fancy as a camera; he had one of those "claw" things that you use to pick up things you drop behind the washing machine. He said he could not find anything inside. However, I was suspicious of his choice of hole. He had the whole side of the house to drill but drilled above the air brick behind the boiler. Am I being paranoid or ignorant here or is it that he thought there might not be any near a vent?

I will have to have to see if I can put something inside the (still open) hole and see what I can find. Certainly nothing poured out but I did think I saw one or two microscopic white "feathers" fall out.

I will see that my electricity company offers a similar scheme albeit for £20 more. Perhaps I should use them instead; at least I know who they are, though I expect they contract out the insulation work anyway.

Thanks.

[Edward W. Thompson]

You may find your 'electricity company' sub contracts to 'KHI', they certainly don't do the work themselves. Being 70 yrs plus I had the cavity walls in my home insulated for 'free' through my 'energy supplier'. It was KHI who did the job (I live in Nottingham).

As far as I could tell the work they did was fine and was followed up some days later by an Inspector to view what was done and to ask whether I was satisfied with the work and the conduct of those doing it. I was.