Fixing plasterboard/insulation board to wall

[RJH]

How best to do this? I have 50mm celotex and 12.5mm plasterboard to bond to a 3m and 2.2m(h) bathroom wall, which will be tiled over.

[Tim Lamb]

In message , RJH writes

or

You could also use a plastic faced plywood and skip the tiling:-)

>

[RJH]

May well, thanks. Or:

What would be wrong with say 80mm/4.5 screws with the wall plugs driven through the board/insulation, then a 40mm washer under the screw head?

Interesting, didn't know about that, I'll take a look.

Don't tempt me :-)

[DICEGEORGE]

[Andrew]

Nah. Buy some nominal 89mm rounded-corner CLS treated timber (which is probably 92mm) and carefully cut into 3 strips that are 30mm deep by 2.4 metres

Get some 120 mm long 8mm frame anchors and screw through the

30mm deep battens fitted horizontally through the celotex into the wall. Then get a sheet of 30mm thick 'celotex' (actually quinntherm is better than genuine celotex because it has more consistent thickness) and infill the gaps between the battens. Now you have 80mm.

Or if you haven't bought the stuff yet, use 30mm quinnterm for the first complete layers and infill with the remains and a subsequent sheet.