Another poor cavity fill.

[Ki Lo Watt]

I have worked on two jobs recently where we installed new windows/doors to  houses with cavity walls. Both had been retro filled with cavity insulation. On exposing the cavity we were amazed to see the lack of insulation and cavity debris. One customer is getting the firm back to “take a look” under the guarantee. However the windows and door are now installed and I have filled the cavities as best I can before installation was complete.

I will be interested to see the companies response to the missing insulation and their action. I have told the customer not to stand for the old get out of “the work you had done cutting new openings has invalidated the guarantee”. So if you are having your cavities filled check it out on completion.

[supremetwo]

So if you are having your cavities filled check it out on completion.

How exactly?

It's not possible to check subsequently with an optical probe.

A thermal imaging camera scan appears to be the only way - not cheap.

[Ki Lo Watt]

So if you are having your cavities filled check it out on completion.

How exactly?

It's not possible to check subsequently with an optical probe.

A thermal imaging camera scan appears to be the only way - not cheap.

That's exactly what I said to the customer when he said the company would come and have a look at the cavity. Perhaps the chap has got X-ray vision!!

Better to check the work as it's being done. 

[EccentricAnomaly]

I had a house in High Wycombe cavity insulated then, many years later, replaced the bath with one with an integral overflow pipe so (pleasingly from the air-tightness point of view) removed the old overflow pipe. I was surprised that there was no sign of the insulation in or around the hole left.

Maybe it would have been a good idea for the client to have documented the lack with a camera while the cavity was open.

[supremetwo]

I was surprised that there was no sign of the insulation in or around the hole left.

I had a redundant washing machine waste hole that was plugged with a capped piece of plastic pipe. It was a simple matter to pull out the piece and check for insulation, which was insufficient.

When they came back, the operator said his machine back pressure sensor failed two jobs later.

They drilled more holes and blew in more fill, but I still have my doubts.

It was the Mann group whose operators were on piece work; many now retrained for Solar, but the results of that are more-visible.

[wookey]

I think this is very common. Almost everywhere I have opened the wall to check I have founds gaps. So far that's one door, 4 windows, 3 wiring holes, two extension junction wall cuts, one bathroom exhaust fan, and two waste pipes. Only the hole I drilled for the boiler flue was in a fully filled area. The degree of gappage varied from 'some' to 'monstrous'. Cleaning out all the debris in there and stuffing more insulation in is a right faff. 

[marktime]

Just curious Ki Lo, what happens if you go to replace window or door frames and all the beads run out? Got to be a worry 


MarkTime

[StationHouse]

Our cavities are not open around windows and doors so nothing will fall out 

[charlieb]

Just to balance the bad news. I've finally persuaded my aged parents to get loft insulation in, having had the walls done 18 months ago (it's free, but they still don't want it!).   Apparently the loft assessor was impressed to see bits of cavity wall insulation leaking out the tops of the walls into the attic, so obviously not everyone scrimps (and my folks live in a big, akward shaped house).

[EccentricAnomaly]

I suspect it's not so much a matter of scrimping but of settlement and also, perhaps, leaving gaps where the cavity is partly blocked by snots, etc. It was, perhaps, 15 years between the time I got my walls filled and the time I noticed the gaps around the bath plumbing. Plenty of time for the filling to have settled. There was no problem around the kitchen plumbing (directly below).

The builder I'm considering using for the shell of my new build uses sheep's wool specifically to avoid settlement issues. I'm about 99% convinced - it'll be interesting to see when there's 15 or more years experience with his construction system.