Sticking insulated plasterboard to old brick advice :)

[sean oc]

Morning all

Just trying to retain as much heat in my small cold rooms in the house, the two external walls are back brick as per pic. They are dusty now - whats the best way to seal them before i foam insulated plasterboard up

Could i use thompsons water seal which someone's recommended to me, or am i best just brushing as much dust as i can and them use plasterboard foam and crack on.

Thanks for any advice

 

[motorbiking]

What insulated plasterboard are you using? Its probably cheaper to buy standard Kingspan/celotex with a foil backing and plasterboard foam adhesive then standard foam for the gaps, then plasterboard foam the plasterboard on. There is no need to try to waterproof the brick if you have foil backed insulation.

 

[sean oc]

What insulated plasterboard are you using? Its probably cheaper to buy standard Kingspan/celotex with a foil backing and plasterboard foam adhesive then standard foam for the gaps, then plasterboard foam the plasterboard on. There is no need to try to waterproof the brick if you have foil backed insulation.

as its only a small room was going to use Knauf XPS Laminate Plus Insulated Plasterboard Tapered Edge - 27mm x 1.2m x 2.4m
Knauf XPS Laminate Plus Insulated Plasterboard Tapered Edge - 27mm x 1.2m x 2.4m | Wickes.co.uk as the cost wont bad too bad

Thanks

 

[motorbiking]

You are wasting your time with that insulation, it isn't going to make much difference. 40mm (ideally 50mm) of insulation will make it worth the bother and you can find plenty that are foil backed. e.g. Celotex PL4040. It will cost a few quid more per sheet, but will make a big difference.

U value of 0.6 vs U value of 0.3 (assuming your wall is a cavity wall).

 

[sean oc]

You are wasting your time with that insulation, it isn't going to make much difference. 40mm (ideally 50mm) of insulation will make it worth the bother and you can find plenty that are foil backed. e.g. Celotex PL4040. It will cost a few quid more per sheet, but will make a big difference.

U value of 0.6 vs U value of 0.3 (assuming your wall is a cavity wall).

ahh is that poor

yeah cavity walls, yeah want to try squeeze in as much as i can but limited with space around upvc, window frame etc

I could possibly get away with 40/50mm on the long wall, and then drop it 27mm board for the other wall with window in.

 

[Deleted member 292770]

you can insulate the walls all you like. most of your cold is coming up through the floor.

 

[sean oc]

you can insulate the walls all you like. most of your cold is coming up through the floor.

There is no drafts from the floor and its normally carpeted and on the 1st floor and doesn't feel cold. cold seems to sit round the external walls/window mainly

 

[motorbiking]

Yes that would be good. Celotex do a PL4025 for around the window, and you can always extend or replace the window board.

 

[JP_]

Kingspan sticks well to brick with Everbuild DryFix Foam, and plasterboard sticks well to Kingspan with same.
I've been sticking those up, and popping in a few anchors if I feel it is needed. Easy DIY job if you take your time and following the foam instructions, and are happy to hold the boards in place for a bit while it sets (to stop expansion pushing boards out).

50mm kingspan + board will be much better if you can live with a slightly slimmer room - only about 2.5cm thinner than what you're planning

 

[mcprinter]

DIYer

Used Soudal Plasterboard adhesive Foam to stick Standard Plasterboard to 1930s Brickwork.
Advises on the Tin to wet the Wall and Board with Water to aid adhesion.
Worked well.