BATHROOM PLASTERING?

[sheldon1982]

need expert advise again if possible.

i am plastering my friends bathroom on sunday. will multi-finish be ok for the whole room including ceiling or will i need some sort on waterproofer?

he is putting up a new plaster board which is not near the bath tub.

does he need a different plaster board for that wall or not?

thank guys

 

[Richard C]

Multi is fine but if he’s putting new PB in there, it should be MR not standard wall board & if you’re going to skim MR, it must be primed first. If he’s tiling over the PB, it’s better not to skim as it reduces the weight of tiles you can hang on it considerable; 32 kg/m unskimed but reduces 20 kg/m skimmed. If it’s only half tiled, I waste the skim into the PB just below the top row of tiles. You can use MR PB in wet areas but it should be tanked, personally I always use a cement tile backer board here. If it’s studwork then it’s easy fix but on block, the manufacturer’s recommendation says no to dot & dab but it’s perfectly feasible providing you also mechanically fix by screwing into the wall (through the adhesive dabs ever 200 x 200mm) then next day after the adhesive has set.

 

[sheldon1982]

Thanks for the quick response , I will get the mr boards what about the ceiling should I reboard that or just skim it, one more queston what is tanking, I hear this a lot on this site but don't know what it is

 

[Richard C]

If the ceiling is basically sound just prep & re-skim, it should be fine.

Most waterproof adhesive & grout will still absorb water & if (or more likely when) it reaches a PB tile base, it will turn it to mush (even MR eventually) in a very short time; this is why you should always tank wet areas. I prefer to use a waterproof backer board which you can tile straight on to; use only a quality trade flexible adhesive & grout. I’ve been using cement based boards fixed as I explained but these look like they should be easier to fix;
Marmox
I’ve not personally used it yet but many are singing it's praises. 6mm & 12.5mm available but 6mm not suitable for studding.

Tanking introduces a waterproof membrane between the tiles & the tiling base & comes in two forms;
A paint on solution (probably the easiest to use for most);
http://www.bal-adhesives.co.uk/products/wp1-coating (joints must be taped)

or a physical waterproof membrane which is stuck in place;
http://www.tilefixdirect.com/product/GTGMAT1.html

Several versions of each available.

 

[sheldon1982]

cleared up nicely

thanks again r c