Wall Preparation Problems - Tile Advice

[grahamt]

Hi,
I'm retiling my bathroom and would appreciate some advice about the preparation needed.

The bathroom has been partially tiled in the past and I am now wanting to tile the whole thing. On the previously tiled areas some of the plaster came away when the old tiles were removed so there is a mixture of old and new plaster. As recommended by my local tile shop, I am going to paint these areas with Dunlop Universal Bonding Agent and then use Mapei MapeGrip D2 adhesive.

The rest of the bathroom was previously wallpapered on top of some areas of bare plaster and some of paint. To try and remove the remnants of the wallpaper paste I used Sugar Soap but found that the wall still felt sticky afterwards. I also found that the wall felt slimy and is covered with a thin film of white rubbery residue that can be scraped off. I have a recollection that before putting on the wallpaper I sealed the walls with PVA. After reading all the warnings on this site about PVA, I am wondering whether I need to go through the laborious task of scraping off all the residue or could I simply sand and score the surface.

Any advice would be much appreciated.

Cheers,
Graham

 

[White Room]

That sounds like a pva as well Dunlop Universal Bonding Agent.

Are all the walls a gypsum plaster.

What tiles are you fixing to the walls

 

[merlecollins]

Hi,
I'm retiling my bathroom and would appreciate some advice about the preparation needed.No Probs

The bathroom has been partially tiled in the past and I am now wanting to tile the whole thing. On the previously tiled areas some of the plaster came away when the old tiles were removed so there is a mixture of old and new plaster. As recommended by my local tile shop, I am going to paint these areas with Dunlop Universal Bonding Agent and then use Mapei MapeGrip D2 adhesive.PLEASE NO!! Firstly how thick are you patching up and what will the patch ups be onto plaster or brickwork or render

The rest of the bathroom was previously wallpapered on top of some areas of bare plaster and some of paint. To try and remove the remnants of the wallpaper paste I used Sugar Soap but found that the wall still felt sticky afterwards. I also found that the wall felt slimy and is covered with a thin film of white rubbery residue that can be scraped off. I have a recollection that before putting on the wallpaper I sealed the walls with PVA. After reading all the warnings on this site about PVA, I am wondering whether I need to go through the laborious task of scraping off all the residue or could I simply sand and score the surface. I would definately get it off mate, even if you've got to use some kind of sander although this might clog up quickly if the residues are soft. Have you tried going over the tackiness with another dose of sugar soap?

Any advice would be much appreciated.

Cheers,
Graham

 

[Colour Republic]

Can you remember if the wallpaper paste you used was in powder form or ready mixed?

To get any residue off, fill a large pump action sprayer with hot soapy water (can get these for a gardening centre for about a tenner) spray the walls and leave for 5-10 mins, spray again them start washing of with a good sponge, rinsing the sponge in a bucket of soapy water every minute or so, let it dry overnight, then sand off with a palm sander - with the palm sander don't buy the pre-made sheets (very expensive) go to your nearest decorator center and buy a roll of aluminum oxide paper and cut to size (5m about £6) most of the residue would have come off when washing but sanding will get rid of the snots, you don't have to go mad with the sander, a 3mx2m wall should take you about 10 mins.

oh it should be said don't buy a palm sander with a velcro base get one with clips on the side

 

[grahamt]

Wow - I am amazed at the number of answers received already and how quick you were. Thanks to all of you for your advice.

Whitebeam - I've no idea what the plaster might be - the house was built in 1952 if that is any guide.

Merecollins - in some cases the top layer of about 1 or 2 mm came off but in other areas I found that the plaster underneath was cracked and crumbling so took it back to the brickwork. The biggest area was about 6 inch across. To patch them up I have used Polycell MultiPurpose on the thin areas and Polycell Plaster Repair where it went back to the brick.

Colour Republic - a powder wallpaper paste was used - can't remember the brand - I've been putting off the redecorating for years so it was a long time ago.

Thanks again,
Graham.

 

[White Room]

The walls are not the gypsum plaster, they are probably sand/cement with 2-3mm siripite finish

 

[Colour Republic]

- a powder wallpaper paste was used - can't remember the brand -

Thanks again,
Graham.

oh ok...

Powdered pastes are mostly cellulose based sometimes starch

Ready mixed tubs are mostly PVA and again sometimes wheat based