what sort of wall insulation?

Gussoe

I'd like to insulate a north facing wall of my house. It's an old house constructed of stone walls, then there's a layer of rendering, then paint. It's a little damp but not growing mould. Space is tight so i'd like to avoid creating a cavity with studs.

I've seen videos of insulated plasterboard direct onto the wall with dabs of adhesive, then wall anchors and this looks like a project could undertake.

But do I need to get the insulated plasterboard with Foil to create a damp barrier or would just insulated plasterboard do the job?

mickdw

I would never fix insulated board to a damp wall directly.

You can get very slim metal stud system that fixes to wall floor and ceiling. You could just leave a 15m gap then stud you would only lose an additional 30mm or so versus fixing direct to wall.

Gussoe

https://www.boards.ie/discussion/comment/118915383#Comment_118915383

I'm not able to link to things, but if you google search "How to Dot & Dab Insulated Plasterboard - a DIY Guide" it will go to this video of a guy in england doing it.

Gussoe

https://www.boards.ie/discussion/comment/118915383#Comment_118915383

Can you show where these very slim metal studs are?

Lumen

https://www.boards.ie/discussion/comment/118915563#Comment_118915563

IMO this is not an appropriate approach for a solid masonry wall.

Consider something like the Isover Optima system. This isn't a recommendation, it's just an example of slim metal studs being used with vapour permeable insulation on an uneven wall.

https://www.youtube.com/watch?v=q7PUrY6Qv1E

Gussoe

https://www.boards.ie/discussion/comment/118916533#Comment_118916533

Those studs might be interesting but overall that cedes too much space. In addition i have a couple recessed windows to deal with and the thickness of studs+insulation+plasterboard is too much for windows, and a new PVC door.

mickdw

Dot and dab is fine as long as the wall is solid and dry.

It's not suitable for an old damp wall.

Look up gyproc universal wall liner system.

It uses adjustable fixings back into wall and allows for quite a slim build up.

Lumen

https://www.boards.ie/discussion/comment/118916942#Comment_118916942

Ah yeah the Gyproc system seems to specify phenolic foam insulation which is going to be far better than mineral wool for a given thickness.

Minimum thickness seems to be 85mm (25+60) for 0.33 W/m2K or 115 (25+90) for 0.23 W/m2K, according to Table 2 of this:

https://www.gyproc.ie/sites/default/files/GypLyner.pdf

C. Eastwood

Gussie

here is a post I gave recently but it should be useful to you.

if there is dampness on the inner face of the external walls caused by rising damp, it needs to be investigated to reduce or stop it if possible. 

if it is caused by ingress of rainwater then that should be investigated and stopped. 

A new floor could be installed. Kept approx 70 mm from the walls below floor level, to form a cavity between the edges of the 150 mm floor and external walls.

The DPM /Radon is brought up the side perimeter of the concrete floor and folded on to the to the top surface of the floor.

Construct a metal Stud Partition on top of a DPC on top of the DPM/Radon. This can be a 100 or 150 metal Stud Partition, which is approx minimum of 50 mm away (cavity) from the external walls, to be fitted in accordance with the manufactures instructions. 

This cavity between the external wall and Stud partition must be adequately ventilated in accordance with the Building Regulations.

Fit approved Insulation in to the metal stud partition in accordance with the manufactures instructions, Fit Services etc. and fix Airtightness membrane, and fix plasterboard slabs and apply skim of plaster. 

There will also be a need to attend to many other details of items of works. 

Any damp - don’t use timber and ventilate the dampness out.