our house (1920s semi) qualifies for free cavity wall insulation – however there is detritus in the bottom of the cavities that will need clearing before they will do the insulation

has anyone done it themselves or is it a builders job? and what is a likely cost?

We also have a badly laid drive that is covering the Damp Proof Course 🙁 so we will need to create a trench before tackling (or not) the cavities.

Any ideas or words of wisdom?

What access have you to the cavity ?Would an industrial hoover and 50mm pipe used for gutter clearance be of any use

not sure a 1920s house will have a proper cavity for insulation. it might have two faced walls rather than a solid one but the gap in between wont be like a modern cavity.

Our Victorian school (development project) has a cavity and even cavity ties. Never seen anything like it. It’s a bastard of a job to clear out and one we’re not going to undertake. Easier to insulate inside.

it does have a cavity, Mrs Ed had the man from British Gas do the assessment for free cavity wall insulation, he brought a camera, hence why we know about the shite in the bottom

hmmm yes, there are airbricks, <goes googling for industrial hoovers>

A builder who did some work for me said he hired a tool designed to remove the mortar from around a brick or bricks to get access to the cavity.

Anyone know if my new (ish, 2007) build is likely to have insulation in the cavity? Can I check? I’ve seen someone getting an extension and they put in solid insulation panels inside the cavity (but still leaving a gap). Is this kind of thing mandatory on new builds or what?

Why not worry about all the shite and just inject higher up? Would be less hassle but may leave wall cool at base I suppose, but heat rises in any case so surely not a massive issue

Molly are you being serious? It will certainly have cavity insulation and in even in 2007 I’d expect to a good value.

Molly are you being serious?

Yes, I’ve got no idea about building regs, that’s why I asked 🙂 Thanks.

When did they introduce this requirement?

We got British Gas out to do a survey on our ’30’s semi for cavity insulation. Turned out there was already some in there – the previous owners must have had it done.

I subsequently cut out under a window to fit some french windows and had to remove a load of it. There wasn’t brilliant coverage, it has to be said, particularly at the base of the wall.

Maybe have a bit of a read up about CWI, and take into account the age of your house and where you live. I’m not against it per se, but I read quite a bit about it when we were having big damp problems, and leaving out the extreme pro and anti views, the considered opinion seemed to be that location and house type had a bearing on whether or not it was a good idea. We have a 1950s house in the NW Highlands, so we get a lot of rain, some of it sideways! The insulation in our cavities was wet enough that you could squeeze drops of water out of it. Once we had it all extracted – which cost about £3-4000 if I recall correctly – the house dried out perfectly. I won’t be putting it back in. Of course there are some companies or subcontractors who do a shoddy job, which might contribute to problems people have? There is a financial incentive for the energy companies and their CWI subcontractors to get people to have it put in, which might I suppose impact on the impartiality of the advice that is given!

wwaswas – Member
We got British Gas out to do a survey on our ’30’s semi for cavity insulation. Turned out there was already some in there – the previous owners must have had it done.

You can sometimes see whther it’s already been done from the little dabs of mortar where they drilled the wall to squirt it in.

I was going to look into getting our house done (moved in about 3.5 years go; it’s a 60’s detached house) and I noticed there were mortar circles all over the exterior walls, so pretty sure it’s already been done.
Dread to think what it was like before it was done, as the house get pretty cold.