Can I use BAL Single Part Flexible on these surfaces?

[zappastix]

Hi

This post is for TWO different walls.

WALL ONE

I have removed all the old 6"x6" tiles and have been left
with a lot of ready mixed tile adhesive stuck to the wall.

I have scrapped hard at every bit and removed all that
is loose.

The white (B&Q type of adhesive) comb bed is
between 1 mm and 2 mm.

20% of the wall in different areas has the top plaster
coat missing (stuck to the old tiles).

This top coat is possibly less than 1 mm.

The bonding that is exposed is not a "pink" colour
but a fawn colour, as is the top coat.

WALL TWO

Same tiles, same room - but this time all the tiles came
off easy, leaving ALL the adhesive behind which is
stuck (sorry) like glue.


MY QUESTION

Can I use BAL Single Part Flexible straight on
to these 3 surfaces without any preparation?

i.e. 1/Top coat - 2/Bonding - 3/Old Adhesive

Or should I PVA 1 in 5 the whole surface?

If so - regular PVA or waterproof PVA ?

The tiles are ceramic 300mm x 400mm for
the bathroom.

Many thanks in advance, Stephen

 

[Richard C]

To avoid serious adhesion problems, you should always use a cement powder adhesive for anything over 300 x 200mm, not tub mix but I'm unsure why have you chosen single part flexible? I'm also a little confused by the rest of your post but here is some info, perhaps it will help make things a little clearer

Finish plaster is not recommended for more than 20 kg/sqm including adhesive; what is the weight of your tiles? Bonding plaster & most other gypsum base plasters are not suitable for tiling onto, let alone for large format/weight tiles; what makes you think you have Bonding Plaster? Given the above, you must at least get all the old adhesive off & get the tile base as flat as possible, particularly with large format tiles; if you don’t they will be all over the place & look awful.

Never, ever use PVA on a tile base; far from providing better adhesion it will make matters worse, particularly in wet areas. If you need to prime, generally, use either a Polyester or SBR based primer but only use it where recommended by the tile adhesive manufacturer.

 

[tictic]

get the steam stripper looked out and get all the old adhesive of them walls first..bit of elbow grease thats all it takes.

then if there is not much damage you could use bal quick render or mapei nivoplan to skim them walls.

then as rich has said re:adhesive and primers.

 

[zappastix]

Thanks for the replies.

Richard C - It took me ages to track down the correct adhesive because
I have very old vinyl floor tiles that are more likely than not to contain asbestos.

I phoned and spoke to BAL technical department and they said
"single part flexible" it the correct adhesive for asbestos tiles.
The BAL (grey) single part flexible was I thought, cement powder adhesive.

This "single part flexible" is suitable for walls as well.

The tiles are Natural Stone "effect" from Wickes - 8 tiles per box = 1m2

A box feels a lot lighter than 15Kgs of dog food, so I'm okay there.

I almost sure that under the top coat plaster is bonding, because I have
just had to bond around a new opening and window I've just installed.
Although it is not Thistle pink, the texture of the finish on the wall I will
be tiling on is the same as the new bonding I have just finished. Rough texture.

tictic - I didn't understand your bit about the steam stripper - are you
saying that a steam stripper will actually break through this adhesive?

If so I wish I'd know this, as I spent a whole day removing the tub adhesive.

 

[zappastix]

UPDATE

I have just found out, that the fawn coloured bonding coat might be CEMENT/SAND rendering.

If it is, can I STILL use SBR primer?

I ask because BAL info/pictures does not state a primer on cement sand rendering.

I don't want to mess up!

Thanks.

 

[Richard C]

It took me ages to track down the correct adhesive because
I have very old vinyl floor tiles that are more likely than not to contain asbestos.

I though you said you were tiling 2 walls, I’m now a little confused I don’t see the relevance of vinyl floor tiles or the asbestos, can you explain a little more? Even so, why not just remove the vinyl tiles, if there is asbestos in them it’s likely to be low grade but you would obviously need to check. I'm not convinced that you aren’t unnecessarily over complicating matters

I phoned and spoke to BAL technical department and they said
"single part flexible" it the correct adhesive for asbestos tiles.
The BAL (grey) single part flexible was I thought, cement powder adhesive.
This "single part flexible" is suitable for walls as well.

That explains it; but still confused about the vinyl/asbestos thing above.

I almost sure that under the top coat plaster is bonding, because I have
just had to bond around a new opening and window I've just installed.
Although it is not Thistle pink, the texture of the finish on the wall I will
be tiling on is the same as the new bonding I have just finished. Rough texture.

The colour of Bonding or finishing plaster means nothing, it can be pink or grey & depends which part of the country the materials are quarried & refined to product. The texture is more of a give away, Bonding plaster is very soft & you can easily stick your finger nail into it

tictic - I didn't understand your bit about the steam stripper - are you saying that a steam stripper will actually break through this adhesive? If so I wish I'd know this, as I spent a whole day removing the tub adhesive.

Yes he is; but don’t leave a steamer in one place for too long or you’ll overheat the plaster & blow it off the wall.

UPDATE
I have just found out, that the fawn coloured bonding coat might be CEMENT/SAND rendering. If it is, can I STILL use SBR primer? I ask because BAL info/pictures does not state a primer on cement sand rendering.

I did say never use PVA & only use a primer if recommender by the adhesive manufacturer. Most cement powder adhesives including BAL do not require a primer on cement screed/render or ply & it can affect initial tile adhesion; can be a problem with large heavy tiles. However, you do seem to have a mix of materials, some of which are most likely gypsum plaster & this must be primed when using cement addy to prevent a reaction between the plaster & cement; In this case, prime the lot with an acrylic primer (BAL Prime APD) it will cover all eventualities & won’t do any harm.