Insulating masonry walls

[Deejay]

Hello all, especially the builders out there.

The back wall of my living room is not built straight. I've just fitted a patio door and while I'm reinstating round the opening I want to straighten out the inside using studs fixed to the wall. They will vary in thickness between 30 and 100 mm over a length of about five metres and be clad with plasterboard.

At the same time, I want to improve the insulation of the wall.

There is no evidence of moisture penetration on the existing (externally rendered) wall. Some of the wall is solid (9" brick) and some of it is has a cavity.

I have a few of questions.

Should I fit a breathable membrane? If so, where, i.e. behind the studding or on top of it?

Any suggestions for insulation material? I think Rockwool might be suitable, due to the difference in the gaps behind the surface of the studding. I don't fancy the insulation backed plasterboard since I would lose too much space at one end.

Any advice welcomed.

Cheers

Dave

 

[J D Architectural Joinery]

for palsterboard you could use a toughcheck foilbacked plasterboard, rock wool or rocksill will probably be your best bet as you will need a minimum of 50mm for any foilinsulation just for the cavity needed to both sides of it.

 

[christoph clark]

Here in france you can buy a plasterboard with the insulation stuck on the back side. you sick this to your wall using a glue type ciment . leaving an air gap.
My whole house is insulated like this..

 

[RogerS]

You can get polystyrene backed plasterboard that is about 45mm total depth. 16 quid a sheet from Travis Perkins and that is with an account. May be cheaper elsewhere.

Re breather membrane...purists will say yes...pragmatists will say don't bother. You might find it worh posting on askthetrades.co.uk.

If you go down the polystyrene backed route make sure you don't let any mains cables touch the polystyrene as the plastics in the two intereract.

 

[Jake]

It wouldn't be a breathable membrane.

 

[Deejay]

Thanks for the replies.

I took Roger's advice and posted on Ask The Trades.

The solution seems to be foil backed plasterboard, as David suggested, with Celotex or Kingspan fitted behind it.

Cheers

Dave