I am insulating the inside of an existing external wall. It leans slightly outwards. My internal (70mm deep) studs are vertical and the insulation goes between them, and plasterboard will go on top. Building control have aproved the thickness of insluation. Wall is 100mm thick concrete block.

The insulation (Ecotherm = Celtotex type of stuff) wedges between the studs but there is a gap behind it increasing with height because the wall leans out but my studs are vertical.

Would it be better (1) to press the insulation right back against the wall and leave the gap immediately behind the plasterboard, or (2) have the front of the insulation flush with the front of the studs leaving a gap between insulation and exterior wall. Maybe (3) it does not matter.

The gap varies from 0mm at the bottom to about 50mm at the top.

Opinions anyone?

thanks,

Robert

On Wed, 5 Sep 2012 06:52:45 -0700 (PDT), RobertL wrote:

Would it be better (1) to press the insulation right back against the
wall and leave the gap immediately behind the plasterboard, or (2) have
the front of the insulation flush with the front of the studs leaving a
gap between insulation and exterior wall. Maybe (3) it does not
matter.

2.

A single block wall will be damp, maybe not a lot but it will be you need
some ventilation to get rid of the damp.

You don't mention a vapour barrier, that needs to be on the warm side of
the insulation. It will be easier to tape the joints (board to board and
board to studs) if everything is flush.

--
Cheers
Dave.

On Sep 5, 4:43*pm, "Dave Liquorice"
wrote:
On Wed, 5 Sep 2012 06:52:45 -0700 (PDT), RobertL wrote:
Would it be better (1) to press the insulation right back against the
wall and leave the gap immediately behind the plasterboard, or (2) have
the front of the insulation flush with the front of the studs leaving a
gap between insulation and exterior wall. * Maybe (3) it does not
matter.

2.

A single block wall will be damp, maybe not a lot but it will be you need
some ventilation to get rid of the damp.

You don't mention a vapour barrier, that needs to be on the warm side of
the insulation. It will be easier to tape the joints (board to board and
board to studs) if everything is flush.

--
Cheers
Dave.

Yes, I agree. I'd keep the insulation in line with the front of the
studs. Have done, in fact, and fixed it there with expanding foam
round the edges for an airtight fit.

Cheers
Richard