Personally, I'd use 4" No 10 screws and brown plugs, every 600mm.
As its a kitchen wall and there are wall units going on it, I'd put 75mm x 50mm noggins in at the height where the wall unit brackets are going to be fixed. Plan ahead.
Thanks - so space the studs at 600 rather than 400 (16"?).
Re: vapour barrier - if on a 4m wide roll, for my 2.7x7.5m wall, do I buy 7.5m and cut the exces/waste or 5.5m and run it vertically with a join? If so, what do I tape the join with?
alternatively, if you're putting cabinets up, use 12mm plywood instead of plasterboard at the top wo you can screw the uppers where you want them.. it's what I did and then tiles under the cabilenets..
the spacings for your studs depends on what size plasterboard you can get in.. 900 wide boards then you want 450 centers, 1200 boards and you want 600
Another issue for this job is that I have enough roll insulation and some 40mm rigid insulation to do a third of the wall... I'm going to buy some 50mm rigid ins but I'd like to use up what I have too!... is it ok to use a combination of roll and the 40mm rigid ins ie. together to give a similar heat retention to the 50mm rigid?
I did mean the screw spacings on each batten. I'd go for 400mm spacing of the battens though. As Coljack says, you could use 12mm ply at the top where the cabinet brackets fix to the wall, instead of noggins.
Dunno about the insulation bit though, I'd prefer to use the same sort throughout.
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