Replacing shower tiles, just adhesive needed or some kind of sealer?

[nuzuki]

Hello,
I have some tiles that came loose and grout kept cracking in our shower. I've managed to get the tiles off in one piece and have sprayed the area with black mould remover. I currently have a fan on the area drying it out. Do I just refit the tiles with adhesive and then grout or do I need to add some kind of sealer like sbr bond, pva or tanking? It appears to be just plaster behind the tiles. Previously I'd regrouted the tiles maybe 4 or 5 times but want to do the job properly this time round. Any advice is greatly appreciated
Thanks

 

[ree]

You appear to have plasterboard with perhaps a skim finish. But why dont you investigate further?
The horizontal join doesn't appear to have been taped.
There's very little evidence that tile adhesive was applied correctly - which probably means that all your remaining tiles are at risk of becoming loose.

Your call but you are in-between a rock & a hard place: best practice would be to remove all the tiles, & replace the plasterboard (if it is P/B) backing with cement board with taped joins.
The tiles can be rescued by soaking them, and cleaning off all old adhesive residue.
Most important you will need to follow the mixing instructions (its on the powder bags) for fresh adhesive.
Use a 10mm trowel to comb the backing boards and butter the back of each tile or length of mosaic.

 

[nuzuki]

Thanks for your reply. I have some mapei super grab premixed tile adhesive. Is this OK or should I use cement based adhesive that i mix myself? It seems there's no backer board. I was going to add some sbr bond and then retile. Then add vitrex tile and grout sealer. I realise it's not been installed properly by the last owner but I'm hoping my fix will be sufficient for a year or two till I can get round to replacing all the tiles.

 

[flameport]

I have some mapei super grab premixed tile adhesive. Is this OK or should I use cement based adhesive that i mix myself?

Premixed tub slop is generally to be avoided, but in this case the whole lot is a disaster from the start.
If you just want a temporary fix the tub slop will be as good as anything.
A cement adhesive may cause further problems as it can react with plaster in ways that cause tiles to fall off.

Ideally the whole lot need to be removed and replaced, plasterboard and plaster should never be used in a shower area.

 

[nuzuki]

Thankyou for your reply. Yes I understand I need a backing board but don't want to strip the whole thing back. I was thinking of adding a tanking slurry to the plaster where the bottom two rows of tiles shall be. Then adding sbr and then adhesive/tiles and grout etc. Probably follow up with a tile and grout sealer made by vitrex. Do you think this will be OK? Most tanking slurry seem to be added to the wall before plastering but wondered if there's any gain to adding it after.