Almost suicidal now :-)

[Gixerguy]

Hi, Thanks for taking a look at my questions, I'm lost in a world of tiles, PVA, Primer G and desperation LOL! I'm just like so many other guys - I'm practical and will give it a go but invariably screw it up...... seems tiling is another one I've screwed up!!

I have had my bathroom ripped out, and replastered professionally from bare brick with a base and finish coat. It has had about 6 or 7 weeks to dry. I sought advice from a 'qualified tiler' who advised me to prime the walls with a 3:1 mix of PVA and off I go, stick the tiles on the wall. All went well, I was impressed with the job until they fell off, leaving adhesive (ready mix wickes waterproof stuff) on the wall but clean tile backs..... what have I done wrong!

I've read so much on t'internet about yes and no to PVA and other primers and brands and I'm lost as to what product I should use lol

Could someone advise me in 'simple' talk, just brand names/product as to which thing to stick to what first lol I'm a mechanic by trade so step by step simple stuff is my level LOL

The tiles are ceramic, and the walls are regular brick, with plaster finish.

Now I have adhesive and PVA on two walls, is there a trade method of removing it to allow the correct products to be used, or do I need new plaster skim?

Also, I'm hearing about tanking the shower area with BAL WP1, is this the right route to go down? from your forums I get the impression it is, with the right primer used everywhere else?

Thanks for any advice given, it is much appreciated - I won't be asking THAT 'qualified tiler' in future LOL

Cheers!

 

[Gazzer]

Firstly removing the adhesive should be easy, just a good scraper and it should be done. if it proves harder than that then wet the adhesive and then scrap off.
NO NO NO to PVA.
You need not prime if you were using ready mixed adhesive but it wont hurt....thats if you used a primer...NOT PVA.
As for tanking then it would be advised but not strictly neccessary . Its your choice, in a high use shower i would say YES, occossional use then maybe.
When you have cleaned the old adhesive off, try and wet the walls again and most of the PVA will come away. You may find it has skinned over too, i would lightly sand the walls to remove as much as possible.

Now for retiling, i would prime with an acrylic primer and use a cement based adhesive.

 

[Gixerguy]

Thanks for your reply Sir, that sounds like a good plan!

I said I'm simple so can I ask - an acrylic primer, would that be Primer G?
and a cement-based adhesive - would that be a Mapei product or could I use a ready mixed one from B&Q for example?

Thanks again for any advice guys!

 

[peckers]

As you have used pva i would have expected the adhesive to be stuck to the tiles and not the wall, as they have all come off!! It sounds either the adhesive had started to cure(to long an open time before the tiles were bedded on the adhesive) or as i havent used the wickes adhesive before it isn't man enough for the job?
But to rectify the problem you now have!
1 scrape the adhesive from the walls should remove easily,if not then dampen with warm water and then scrape off!
2 once adhesive is removed wash walls down with warm damp sponge to get rid off the pva residue! may need doing more then once?
3 Sand down walls with a 60-80 grit sand paper to give a good key for new adhesive
4 apply an acrylic primer to the walls
5 To be on the safe side i would tank the shower area! imo
6 Re tile using cement based adhesive(it has to be cement based if you are tanking the wet area!! If you dont tank then you can use pre tubbed, (some pre tubbed adhesives are self priming so you dont have to prime the walls first, but i would make sure it is a good make like bal white star etc! and read the instructions as to if you have to prime!

Hope this helps!!!

 

[peckers]

Thanks for your reply Sir, that sounds like a good plan!

I said I'm simple so can I ask - an acrylic primer, would that be Primer G?
and a cement-based adhesive - would that be a Mapei product or could I use a ready mixed one from B&Q for example?

Thanks again for any advice guys!

Mapei primer g is fine i wouldnt waste your money on b+q or wickes adhesive again for only a few quid more use either mapei/bal/granfix etc!
you can get these from your local stockist tile shop!
Cement based adhesive is one that you mix yourself and is available from tile shops and i would use a white one rather then grey! for ease of cleaning the joints before grouting!

 

[Gazzer]

A cement based adhesive is one that you will mix with water yourself. if you use this type then yes you need to prime. Primer G will be fine for that.

I would not bother with B&Q for ready mixed adhesives although they do sell a cement based adhesive which is made by Mapei, using a white adhesive is recommended too.

 

[Gazzer]

Snap

 

[peckers]

Snap

:lol::lol:

 

[mikethetile]

everyone else has given the same advice as i would have

im surprised the addy stuck to the pva walls and not the tiles, i can only think that you nspread the addy too far for your speed and it skinned over

sand the walls well as the pva soaks into the surface sealing it when the addy rewets the wall it reactivates the pva causing a barrier

theres no need to prime if your using tubbed addy but there is if you use powder

theres no harm in priming anyway but priming over pva wont solve your problem

 

[Ajax123]

Whilst I can add nothing usful to the above comments I will point out that this installation has not failed IMO because of PVA Use. If that had been the culprit the adhesive would have still been on the backs of the tiles. In this instance of course it sounds like a tubbed adhesive has been used. These rely upon them losing water to set. If you seal your walls (even with PVA) this reduces the level of suiction the exert and so the drying of the adhesive takes much longer. You therfore cannot grout for some considerable time in this scenario. Skinning to the surface of the adhesive prior to tile installation may also have contributed. I know that the pro tilers don't generally like tubbed addy but I as a DIY tiler have used loads and never had an issue but I have also never primed a substrate when using them.

If you use a bagged cement based adhesive it relies on chemical reaction so you don't want the walls to exert too much suction on the adhesive as this would cause adhesive dessication (over rapid drying) and it does not set to its full strength hence you use a primer to reduce the suction. I have to admit that in my most recent installations I have used bagged cement based adhesives.

You also need the primer to reduce the migration of reactive sulphates between the gypsum plaster and the cement in the adhsive. In very low moisture systems such as walls an acrylic will normally do this effectively enough. My over riding advice where cement and gypsum are to be mixed however and most especially if it were a gypsum floor however would be epoxy primer every time.

Just thought it might be useful to try and draw some consclusions as to what went wrong in the first place.