Peoples thoughts on cavity wall insulation.... Is it worthwhile?

[cheekychopsmum]

I've just had an old chap come to the door trying to sell cavity wall insulation - they are currently doing an offer of £150, but I just don't know what the pros and cons are.

He seems to think we will qualify for some kind of grant to bring it to the above price, but I hate dealing with anyone who comes to the door. What are peoples opionons, and has anyone had it done? Have you noticed a difference in house bills/heat of home?

I don't understand why fill the cavity, cos it is there for a purpose isn't it?

there seem to be so many companies out there, how do you know who to go to and f they are legit? Questions questions, I know, but I am intrigued

My local council does it free if you have kids under 6, are over 60, or on certain benefits so it may be worth checking that first(they also do loft insulation). We had it done under that scheme and I'm sure it makes a difference.

Find out about council grants first of all, they may also have a short list of companies used in connection with the grant (if so that saves you the hassle of researching them). We couldn't get it free but got it for £99 which is much less than the usual price, and we are not on any benefits.
On paper it's definitely worth doing, only thing is when we had it done because we have a gas fire in one room (even though it is NEVER EVER used!), they had to put a vent in the wall in that room due to some safety rules; and we found lots of cold air came through the vent so it actually felt colder in that room after it was done! Doesn't seem right to me... but generally you should find it cuts the heating bills.

The cavity is there for insulation, as it gives you a layer of air which helps keep the heat in vs. a single wall where you have the cold "outside" air directly on the other side. But if it's filled with something more insulating than air (i.e. foam), that increases the heat-keeping effect. At least that's how I understand it!

If you do go for it, talk to the company and make sure you know where they will need to work and any things that will need to be moved beforehand. They need to drill holes in the walls in LOTS of places to inject the foam, but our company didn't really explain everything they needed beforehand and we had lots of heavy things in the way, and they had also given me wrong info about how long it would take, so I had to send them away and get them to come back another day after I'd moved everything.
Definitely don't use a company just from a doorstep visit, you don't know whether they are legit!

I did some research on this when we were offered it several years ago. Ds1 is on dla so we would get it free. It can cause problems with wall ties if you live in an older property apparantly. As we live in a 1930s house we were advised not to get it unless they would use bonded beads rather than rockwool(??). If it causes problems rockwool (not sure if that name is spelt correctly but it's the stuff that looks like chopped up roof insulation) is nigh on impossible to remove where as bonded beads are not.
My parents have had it done free in their 1980s bungalow with no problems. I don't think they have noticed a huge difference in their bills but their home is definately warmer.

A word of warning about cavity wall insulation.

I bought a timber framed house that had been insulated by the OAP (free of charge under a grant) who I bought from.

When I came to sell 4 years later, my buyers had their mortgage turned down because apparently you should never cavity insulate a timber framed house. The surveyor for the mortgage company just turned it down flat.

After a lot of investigation, (as I didn't have it installed, and my surveyor missed it), I found out who had door-stepped the woman I bought the house from and gave them SO much shit, they eventually agreed to remove it. They were not happy, but I threatened them with legal action (as they should survey your property to ensure it is suitable, and all the house info said it was timber framed etc). My solicitor even had a 25 year guarantee for it . They had no choice in the end and removed it. My buyers were fab, waited for it to be removed, and got a new survey and mortgage after it had been taken out, but it cost the compant a lot of money.

It was a very stressful time and I was incredibly lucky to have buyers who really wanted my house....if that had been me, I would've walked away.

If your house is suitable, it can really cut down on heating bills....but please do your research first.

Thanks for all your advice, really useful - especially about the wall ties problem, our house is 1930's and I do remember now that it was mentioned in the mortgage survey that the wall ties may need looking at in future. The cavity wall insulation I'd looked at was for rookwool, so it would need more research..... maybe I'll just start with getting the loft insulated!