Plasterboard repairs prior to re-tiling

[Oddbod]

I've set about replacing our shower and the tiled area above it. The old shower's out, but getting the tiles off the wall has been a chore because they were well stuck with a black bitumen-like adhesive. The wall is a stud wall, with dual sheets of plasterboard, and removing the tiles has resulted in some fairly large chunks (max 15mm deep) of the plasterboard surface having pulled away.

The damaged area overall isn't really big enough to warrant cutting out and replacing the plasterboard, so I'm guessing it would be okay to fill the damaged areas with some kind of plaster or adhesive, and this is where I need some advice.

I did buy some 'finishing plaster' assuming this would dry hard and strong, but it's nothing like. It's dried brittle and dusty, is cracking, has failed to stick to the damaged areas and it's falling out already, so tiling onto that would be a disaster.

Please could somebody advise me what kind of plaster/filler/adhesive I need to use to make good the damage to the plasterboard walls, and which will be solid enough and adhere sufficiently to provide a sturdy base for re-tiling?

Thanks so much.

 

[Deleted member 9966]

how big are the gouges in the plasterboard? if they're the size of the tile you pulled off then you'll start to undermine the integrity of the plasterboard if you tile straight over it. i had the same problem as you but in my bathroom. tiles wouldn't come easily away from the plasterboard so ended up chiselling a few off which left craters in the plasterboard. in those instances we just cut the plasterboard out and replaced it with new.

tiling is all about the preparation. prepping your walls properly will be the start of a beautiful job. if you've just left small 10p size dents in the plasterboard, you might get away with just using adhesive straight over it, but it's better to have fully intact plasterboard to prevent any future failures.

will you be using a tanking membrane before tiling?

 

[Oddbod]

Hello, and many thanks for your thoughts.

how big are the gouges in the plasterboard?

The biggest is about 5 x 3 inches and max 15mm deep. There are four/five at around this size (the rest are much smaller) and they're mostly along the vertical edge of the plasterboard where it butts up against a marine ply base (with silicone in between the two) that substitutes for plasterboard within the shower area. So the damaged area of plasterboard is also exactly where I'll eventually need to tap the screws through the tiles to anchor the shower surround. Hence the need, if repairing this with filler, for a filler which will effectively reinstate the integrity of the original board.

Is there nothing available that would be suitable for this purpose? If not, then yes, I would agree that I'll have to cut out and replace that section of plasterboard like for like.

will you be using a tanking membrane before tiling?

Yes, I was advised to look at Dunlop's 'Shower Waterproofing Kit' (and also their 'Waterproof Wall Tile Adhesive' and 'Anti-mould grout with Microban'. Would you know of anything more appropriate for my needs than these particular products?

I really do want to get this right and make a nice job, so many thanks once again.

 

[Deleted member 9966]

with holes in the plasterboard that big, it will start to lose it's integrity. the best solution is to cut out and replace, or better still, replace all the boards in the areas you want to tile on. this will give you the best substrate for tiling on to.

as for the tanking kits, I have only ever used the Mapei Mapegum kit myself, but a lot of kits are very similar. Mapei also do a roll membrane that you just cut and stick to the walls using tile adhesive.

ready mixed tile adhesives tend to be avoided in shower/bathroom areas because a) they need air contact to allow the adhesive to cure, and putting big tiles over the adhesive stops it from reaching the air to aid curing. (basically you will find it will take ages for ready mixed adhesives to set and b) you're very limited with tile size and weight with ready mixed adhesives, so if you want larger tiles, ready mixed adhesives won't be suitable. what tiles are you going to be fixing and what size will they be?

 

[Oddbod]

with holes in the plasterboard that big, it will start to lose it's integrity. the best solution is to cut out and replace, or better still, replace all the boards in the areas you want to tile on. this will give you the best substrate for tiling on to.

Agreed. I'm starting to get the feeling that this will indeed be the best approach.

as for the tanking kits, I have only ever used the Mapei Mapegum kit myself, but a lot of kits are very similar. Mapei also do a roll membrane that you just cut and stick to the walls using tile adhesive.

Many thanks for this - I'll take a look at these, too.

what tiles are you going to be fixing and what size will they be?

Haven't chosen the tiles yet, but we're more likely to settle on something plain and simple, i.e. lightweight 6-inch squares or thereabouts, rather than anything heavy-duty or elaborate. Nevertheless, I'm still inclined to take your advice to replace, rather than attempt to repair, the plasterboard. And I've also read similar comments about pre-mixed adhesives in the past so I'll take your thoughts on board there too.

Thanks once again for input, greatly appreciated.

 

[Stewart]

Hi there.......... I would recommend replacing all the plaster board, as the integrity is now lost. your also planning on tanking the shower area, so why not replace with one of the several waterproof boards that are available and just tape the joints to tank the area prior to tiling.

 

[kilty55]

plasterboard costs pennies,replace it imo

 

[Oddbod]

I will definitely replace that plasterboard.

And I didn't know you could get waterproof board either, so would never have even thought to ask about that - thanks Stewart.

In fact, my thanks to all you guys here for your guidance and enough moral support for me to go and just cut out the old and start afresh!

Cheers,

Nigel

 

[kilty55]

testing

 

[david campbell]

testing testing 123.................lol:lol:

are you applying for a dj's job jamie?:smilewinkgrin: