Insulated plasterboard advice

[Connor979]

Hi all

I have an old mid terrace property with old uninsulated stone walls. I’m planning on using PIR insulated plasterboard affixed to a 25mm timber batten frame. I was thinking of adding 25mm rock-wool in between the timber battens just for added insulation. However My question is, would this have any negative effect that anyone can think of? My concern was condensation forming.
Would an air vent be advisable also??

Any advice is greatly appreciated. Many thanks in advance.

 

[motorbiking]

Don't batten.

Use Plasterboard foam adhesive to secure directly to the wall and use standard foam to fill any gaps. You will save a lot of money using PIR boards and then foam on plasterboard. Secure each board with 6-9 small frame fixers, which you can then adjust to get each panel level.

Not only will you get better thermal efficiency this way, but you will lose less of the room.

It is vital that all the joints/gaps between the boards are sealed with foam so that no warm moist air from the room can touch the cold external wall.

You want at least 50mm PIR to make it worth the bother. Allowing for the foam gap and foam between boards you will lose about 75mm of the room. But if space is tight the celotex PL4050 can be used with plasterboard foam and hammer/frame fixers.

 

[Connor979]

Thanks for advice.
I was only going to batten the wall as currently the wall suffers from penetrating damp, although all the old plaster will be stripped back and it’s going to be tanked, along with the exterior weather proofed plus new windows, gutters and fascia’s so I am addressing the damp itself, was just concerned if ever came back. Might have just been being over cautious tho so may well just apply straight to wall once tanked.

Would u also foam adhesive the plasterboard to PIR board or just mechanically fix?

Many thanks.

 

[motorbiking]

Another reason not to have a gap. The celotex is foil backed which acts as a vapour barrier. In terms of adhesive I've done it both ways. It depends if you are tight on space or not and would prefer to drill more holes.

 

[foxhole]

Really need to sort the damp , not hide it .

 

[Connor979]

Thanks mate. Think that is definitely the way to go. Is dot and dab still okay to use for solid walls with no cavity? Been seeing some people say it should only be used on cavity walls. Or would it make much difference?

And foxhole, if you read my last message properly I did say the damp is being addressed.

 

[motorbiking]

Dot n dab is ok. But you get better results with the foam as you have a solid bead all around the panel to prevent airflow