Gap under insulated plasterboard and escaping heat? Information, help, tips and advice on cavity walls, ceilings and lofts etc....

[AzK]

Hi

I have bought a couple of insulated plasterboards (Knauf XPS Laminate Plus Insulated Plasterboard Tapered Edge) to go on a ground floor external wall that is cold and it cant be insulated externally.

I understand that on ground floors, you need to leave a 10-15mm gap between the bottom of plasterboard and the floor to avoid any damp or moisture rising up through the board.

My question is as I am trying to insulate a cold wall, do I just leave this gap of approx 10mm x 27mm hollow? I am worried about both heat escaping and also coldness coming through this gap.

I have seen in some places that people suggest using skirting board - whilst this visually covers the gap it doesnt quite deal with the issue of insulating that area.

Any reccomendations or suggestions? Is there a foam or other product I can use to fill to both fill the gap and that is moisture resistant?

Thanks

[stoneyboy]

Hi azk
Probably the easiest solution is to use expanding foam which can be trimmed flush to the wall once set.
Regards S

[AzK]

I think expanding foam might have a similar issue to having the board level with the floor in that is may absorb or attract moisture which may work its way up the board and insulation

[stoneyboy]

Hi ask
If you are concerned about water permability use a B2 foam.
Regards S

[stoneyboy]

Hi ask
If you are concerned about water permeability use a B2 foam.
Regards S

[B4Less]

Hi, did you try any PIR boards?
Regards,
Build4less

[B4Less]

Hi, did you try any PIR boards?
Regards,
Build4less