Attaching Plaster Board to err Plaster Board

[AJ]

Hi All

I need to cover a small bathroom wall with some plaster or aqua board. I'm not 100% sure what the existing wall is made of though, some of it looks like plaster board and other areas have what looks like exposed straw!

The tiler that put the tiles up that I have just removed covered the original wall with some PB. When I removed the tiles it knackered the PB uunderneath hence the need to redo what was done before. The original wall is in a bad state as I mentioned above and it has what looks like straw exposed, it's therefore not a good sound surface for tiles at all.

I was thinking of securing the new board to the wall using the Dot and Dab method with some dry lining adhesive. is this a good way to go? also should I PVA the wall before fixing the new boards. Do I have to worry about the board joins considering its going to be tiled over?

Alternatively should I just use PB screws and be done with that? lot quicker and cleaner.

Thoughts, advice?

Cheers AJ

[Bob Mannix]

If the wall is as you say, PB screws won't work either. Personally (but not having seen the wall in question) I would prefer to skim the wall with plaster. You don't need a mirror surface to tile onto, and it would fill the irregularities. I am just finishing my bathroom and have floor to ceiling tiles that replace old tiles that took the wall with them in chunks and this is what I did (reasonably successfully). Alternatively use a lot of dot and dab so it's as solid as possible. Don't grout where this wall meets another (if it does) grout the flat bits and mastic the join between walls or you will get cracks in the join.

[AJ]

Hi Bob

Regarding the PB screws I was thinking of just using large screws that would screw through the new and old PB and into the Studs that would be ok would it not?

So if I do dot and dab you're saying to fill the joints between the plaster board with tiling grout?

Cheers

AJ

[Bob Mannix]

Well you didn't really say whether the studs were regular and available or findable. Has the "straw" wall even got studs? I would say you need dot and dab splodges bridging the joins so one board doesn't move against another. Difficult to say without seeing the wall!

[Rod]

Remember that proper PB screws are phosphate treated so as not to corrode. They are also designed to run through the PB with minimal damage. Random "large screws" might not be suitable. Proper ones are available in several different sizes:

[Martin Bonner]

I would worry that the studs behind the "straw" wall would be whatever tree branch the builder could find in the local woods. In other words, they may well not be straight or evenly spaced.