Dabs and Dobs

[john]

What mix do I need to attach plasterboard to a brick wall?

[Grunff]

A mix of plasterboard adhesive and water.

[ben]

Plaster

[John Rumm]

A tin of expanding foam filler works very well also...

[madmax]

I doubt that!

[Franko]

Quite right, either Gyproc or Knauf drywall adhesive, mixed to a thick consistency with clean water. Do not try to use anything else as it will not work properly, normal plasters do not have the correct adhesive qualities - DO NOT USE spray foam - umless you want wobbly walls ! Franko.

[John Rumm]

Live and learn then...

been there, seen it, and done it, and it does work very well! ;-)

Just gently spray a thin bead of it (about an inch wide) along the back of the board (I do a lap of the edge a couple of inches in plus a lattice on about 400 centres) and push it onto the wall. It gives a very ridgid mounting with much less messing about mixing either adhesive or bonding plaster.

[madmax]

Have you used it on 2.4 x 1.2 boards or is it just for the small, fit in the back of the car, boards from say Wicks or B&Q? Foam cant have anything like the strength of adhesive which sets harder than other hard setting thing.

Downsides I forsee are

1/ foam continues to expand as it sets so board pushed out from wall. Difficult to line up a few boards. 2/ unlike adhesive it has no grab so you need some elaborate way of holding in position for 10 minutes. 3/ expensive - say £5 per board compared to 50p with adhesive. 4/ the last bit you mention about less messing about mixing plaster, you are still gona need to do that to fill the joins. Adhesive can be used to do that too at the same time all in one go.

[John Rumm]

Yup, I have used in on full sized boards once, although I tend to use it more for fiddly jobs like lining cupboards in a loft conversion (i.e. lots of odd angles and shapes). It comes into its own here since you are often spending a fair amount of time measuring, marking out, and cutting the boards, and the foam won't go off in the bucket like plaster based adhesives will.

In this application (used sparingly) it does not seem to make any difference. The expansion seems to push the foam sideways in the joint rather than the board "out". Once you seat the board where you want it, it seems to stay there.

It actually has a moderate amount of grab (it is also *kin sticky!). Obviously not so much of an issue on vertical boards, might be more so if lining a ceiling in this way... (although I would not use either technique for ceilings anyway).

The whole can costs less than 5 quid (the siroflex one from toolstation for example) and will do many boards.

If you want to do them at the same time, then yes the real adhesive would be better for this. The real joint filler compound even better though.

The foam is slightly better at reducing sound transmission through the lined wall.

I am not suggesting that foam should be a universal replacement for adhesive in the dry lining industry - just that it has useful applications here.

[madmax]

and messy to clean up

of course not:)

When I was looking into it I read on a forum someone who said he did it that way for a living covering X 100 mtrs a day etc. but thats not relevent to amateurs I suppose.

good point, mechanical insulation!

fair enuf!

M