Wall Insulation

[custardavenger]

Hi Chaps hope you can help with this.

I have started a two storey extension to my house, the ground floor of which is a garage.

Unfortunately the builder didn't ask me whether I wanted the wall cavity insulated which I did. I'm now trying to find options for insulating this wall before the build progresses any further.

Currently I have an open 100mm cavity. I have had two insulation companies round. One didn't want to know, the other want's £190 and can't do it till possibly early September which may mean he can't do it at all without drilling as the walls will have progressed by then.
His suggestion to me was to buy insulation rolls and feed it in which I don't think will work because of the ties and the height of the wall.
Only other option I can think of is granular insulation.

Would this be a good idea? If so what type should I use?

 

[Adrian80]

Probably your only soloution is to blow in insulation and fill the cavity completely.

This works out a lot cheaper than cellotex or alike. I suspect it is unlikely that you will get the desired U value for building regs any other way.

You might be able to smack in the massive sheets of cellotex, The wall ties just cut through the sheet as it goes in. The bend some wall ties in half , and push them down to hold the sheets in place. Will probably cut the sheet to shreds.

I would blow the whole lot in.
A

 

[^woody^]

Unfortunately the builder didn't ask me whether I wanted the wall cavity insulated which I did.

LOL ... he's not a builder then

And you can't use insulation rolls anyway as they are not for cavity walls

You need to find out what insulation you can use retrospectively as none of it may meet the required standard, and you may need different internal blocks or additional insulation on the inner face to compensate

And the million dollar question is "What did the plans say?"

 

[custardavenger]

OK. Not working to full architectural plans. Went the building control check route.

I contacted a materials supplier and they suggested Vermiculite, but the quote was twice as much as the cavity wall guy so have asked him to come back.

 

[freddiemercurystwin]

And the million dollar question is "What did the plans say?"