tiling over old tile adhesive?

[stapes]

Hi, I have just started my first bathroom refit - DIY on my own house! I had a bit of a nightmare getting the old tiles off though and want to know how to proceed.
Basically there were two sets of tiles straight onto plasterboard. Looks like the original tiling went around the bath at waist height and someone later extended to the ceiling. The waist to ceiling set came off easy but the original tiles just about the bath have either taken large parts of the plasterboard with them or left a lot of very solid adhesive behind. See picture attached.
So what are my options for tiling this? Can I tile over the old adhesive? Then is it worth filling the holes or should I cut out the plasterboard and replace?
I want to run tile right across the left hand wall which means tiling over painted plasterboard, is this possible? How do I ensure it's level across the painted surface and the old adhesive covered area of the same wall?

 

[peteablard]

Hi and welcome to TF. Your picture doesn't seem to have uploaded so it not exactly clear to see what you mean however personally I'd always remove the damaged plasterboard and replace it. It gives you a brand new surface which will be a lot easier to tile on. It would be worth considering tanking the walls around the shower area. Also you can't tile over paint so you'll have to remove that or replace it. Good luck

 

[PuPPeT]

if you are new to tiling,the best thing for you to do is to remove the old plasterboard and replace it to give you a flatter surface to start on which will make it eaiser.if you try and tile over old adhesive it can be a bit more tricky but it can be done.tiling over painted walls can be done also.all u need to do is to score the surface to give the adhesive something to stick to but make sure that any flaking paint is removed and then PVA.

 

[peteablard]

if you are new to tiling,the best thing for you to do is to remove the old plasterboard and replace it to give you a flatter surface to start on which will make it eaiser.if you try and tile over old adhesive it can be a bit more tricky but it can be done.tiling over painted walls can be done also.all u need to do is to score the surface to give the adhesive something to stick to but make sure that any flaking paint is removed and then PVA.

Is this wind up?????

 

[Stef]

if you are new to tiling,the best thing for you to do is to remove the old plasterboard and replace it to give you a flatter surface to start on which will make it eaiser.if you try and tile over old adhesive it can be a bit more tricky but it can be done.tiling over painted walls can be done also.all u need to do is to score the surface to give the adhesive something to stick to but make sure that any flaking paint is removed and then PVA.

Oh Dear, i do hope this is a wind up Pete, PVA??? PAINT???

Never ever use PVA when tiling, you will find suitable primers if you look through the site & never tile on top of a painted surface.

Remove old plasterboard to give you a nice surface to tile to & remove the paint.

Surface preparation is the key to tiling.

Good luck on your project, if you need any help then just ask.

 

[stapes]

Finally worked out how to shrink the photo size so it will upload!

 

[stapes]

So got the photo up, you can see the worst damage is around the bottom left where the taps were on the bath. Lots of adhesive is still attached on the right hand wall.
So I am going to replace the bath with similar and want to tile all of both walls.
What is the best way to get the plasterboard off? The dot and dab adhesive is pretty strong!
Then what about tanking, I don't want to go too mad as this bathroom will not get much use (we have a small ensuite which is the next project!). What would be the minimum I should do assuming I replace both walls of plasterboard?

 

[Stef]

I would rip those two walls down & replace with moisture resistant plasterboard (green sheets)

I would also look at getting a dryliner in to fix those sheets then they should be nice & flat & that corner should be square.

I would tank those walls for total piece of mind, if water does get behind the tiles then you dont have to worry about it.

Use an SPF powder adhesive, Single Part Flexi, with a long pot life ie 5hrs.

Take your time & browse through the forum & if you do need any help then just keep asking.

Theres going to be a lot of comments on here later about you getting advised to use PVA.

 

[DHTiling]

IMHO the damage does not warrant having to remove the plaster board, dampen the old adhesive with a sponge and after a few mins if it is dispersion adhesive it might soften up enough to just scrape off..

Then sand the areas that are to be tiled to remove the emulsion... if the adhesive does not soften up as it might be a D2 type , then use a razor type scraper to remove as much as possible.

 

[peteablard]

Worse case if it does make a complete mess of the wall you could chop out and replace that section behind the bath. As Dave says it's not worth ripping the rest out. Always difficult to advise without seeing photos

 

[AliGage]

Seriously, the term "PVA" should be added to the censored words list. Anyone found swearing on the forum again should be banned!! lol

The only people that should ever use "PVA" are primary school children and blue peter presenters. Neither of which i would trust with tiling!

 

[Mike Mike]

Seriously, the term "PVA" should be added to the censored words list. Anyone found swearing on the forum again should be banned!! lol

The only people that should ever use "PVA" are primary school children and blue peter presenters. Neither of which i would trust with tiling!

Here's a story you are all going to like. An old neighbour of mine when I lived in London was site manager for a development out in Essex, 5 luxury 7 bedroom houses, with very high price tags. I tiled the downstairs floors in 600 x 600 travertine but they wanted the bathrooms and en-suites (of which there were a LOT) to be tiled on 9mm ply on the floor, unprimed on the underside or edges, and straight onto plasterboard on the walls that had been PVA'd. I refused to do it, citing 15mm ply, primed on the underside and edges, and both the floors and walls needed to be tanked (they weren't wet rooms, but even so, tank the bleeding things for the sake of a hundred quid per bathroom in a £700k house, and don't put PVA anywhere near those walls!).

We fell out over it actually, didn't speak for months afterwards, and he got someone else in who had no qualms about fixing 406 x 406 travertine those substrates. That was 8 years ago. I wonder exactly when they fell off the walls and the floor started tenting??? :lol:

 

[Tony73]

Here's a story you are all going to like. An old neighbour of mine when I lived in London was site manager for a development out in Essex, 5 luxury 7 bedroom houses, with very high price tags. I tiled the downstairs floors in 600 x 600 travertine but they wanted the bathrooms and en-suites (of which there were a LOT) to be tiled on 9mm ply on the floor, unprimed on the underside or edges, and straight onto plasterboard on the walls that had been PVA'd. I refused to do it, citing 15mm ply, primed on the underside and edges, and both the floors and walls needed to be tanked (they weren't wet rooms, but even so, tank the bleeding things for the sake of a hundred quid per bathroom in a £700k house, and don't put PVA anywhere near those walls!).

We fell out over it actually, didn't speak for months afterwards, and he got someone else in who had no qualms about fixing 406 x 406 travertine those substrates. That was 8 years ago. I wonder exactly when they fell off the walls and the floor started tenting??? :lol:

wall possibly will be ok, but 9mm ply on floor -wrong, should be at least 12mm, and ditra matt

 

[peteablard]

wall possibly will be ok, but 9mm ply on floor -wrong, should be at least 12mm, and ditra matt

Floor should be 15mm (BS minimum)

 

[Martino]

I have a few questions about this post...Whats wrong with using pva? and whats wrong with 9mm ply if its screwed every 100mm?

always looking to gain knowledge you see :-D

 

[Olz]

PVA just dries into a thin skin, and its ok at sticking pasta to coloured sheets of paper but that's about it. Think about when you get it on your hands, to get it off you just let it dry and easily peel it off.

Do you really want something so easy to peel off your hand to be the only thing holding adhesive, and therefore the tiles to the wall?




Sent from my iPhone using Tapatalk

 

[Martino]

But then why do plasterers use it on a ceiling?...its the same principle? it dries thin and its the only thing holding the plaster up?

 

[White Room]

Plaster weighs about 2 kg m2...

 

[steve6710]

p.v.a. is used for plastering as it theoretically should never get wet again to the degree tiles in a bathroom or kitchen may. if you paint pva onto pretty much any surface and let it dry for a day, a week, a month or a year it will seem fine untill you wet it. it then turns back to the sticky liquid you started with. plasterers like myself use pva which is the accepted practice but what happens when you have a rising damp problem or a roof or window leak?..... your plaster loses it bond 9 out of 10 .
as another example i am a fisherman who uses pva bags to fill with bait which i attach to the hook, when in the water the pva dissolves and only the bait is left for the fish.
a couple of tests you can do to see the values of pva are: pva a hard surface 6 square inch let it dry - you can sand wood with it
va a hard surface - leave it a day to dry - wet it and touch it- sticky again!slip slide!
sbr is for tiling primer or external plasterwork(render) as it is a latex skin which can handle getting wet again - pva aint bad in the right application if it was for tony hart and morph or blue blue peter it wouldnt be sold at builders merchants i would guess!

 

[steve6710]

sorry to add to previous thread, apply basic sand to the wet pva and allow to dry to make sand paper for the first test i mentioned