Questions about tile adhesives

Leif

As the title says:

What colour is Bal White Star adhesive?

According to the manufacturer, the above requires primer be applied to gypsum plaster if it is polished or shiny. Am I right to understand that polished corresponds to the process carried out by a plasterer after applying a skim of finishing plaster on an interior wall, which makes it suitable for painting? Am i right to think that without polishing, the the surface feels finely rough, a bit like sandstone? Could the finish feel be smooth without polishing?

What colour is Topps Trade Rapid Set adhesive? I cannot find it at Topps, so I assume it has been discontinued.

Sorry for the dumb questions, but there is a good reason.

Oldsoak

O.K. let's take this 1 step at time.
Firstly polished plaster is when the plasterer wets and smoothes over the plaster repeatedly (usually 3 or 4 times will do it).
If you are tiling over any plaster you need to consider many aspects. For the purpose of argument I will give you an example.

Let the plaster dry 24hrs per mm depth of plaster or until it goes an even and lighter shade of the colour it was (grey or tan/brown).
If using small tiles upto 200x250mm then it is advisable to prime the plaster with APD (acrylic primer).
If using larger tiled then you really need to advise the plasterer not to polish the plaster finish or if they have, then you should scatch the surface using a stanley knife or a claw scraper (to slightly roughen the surface), the apply APD (NOT pva), then tile.
Good luck

Oldsoak

If you know what size and type of tile you want to use, then post it and I or some other tiler will tell you what you need to ask for and use. If you give a rough location someone may be able to help or even help with getting trade discount.

har0ld

As a general rule you would expect fresh plaster to have been primed with something like PVA (usually 5:1 ratio with water) before tiling - most adhesives will be fine on this.

Leif

Thank you for the helpful comments.

I should explain that this concerns a dispute with a company that refitted my bathroom, and bodged it. Because I am now writing the document that I will submit to the court, I need to be accurate. I do have three independent surveys, but I need to understand what is going on in case I am asked questions so I do not seem too stupid, and they do not baffle the court with bull.

The fitters did not prime the walls, despite claiming to have used Bal Primer. They now claim the adhesives (including Bal White Star) do not require primer. According to the data sheet of Bal White Star, and the customer services people, gypsum plaster DOES require priming prior to tiling if the plaster is shiny or polished. The bathroom walls were skimmed, then tiled. The surface was very smooth in all areas, including where I removed tiles (ignoring some bits of adhesive). This to me means that the plasterer applied the skim coat, waited a while, then used the trowel to smooth (polish) the surface. Had he not polished the surface, it would have been finely rough, which is clearly better for tile adhesion i.e. more surface area. I am not sure I know what unpolished plaster looks/feels like, although when the good fitters redid the bathroom, they patched the ceiling where the old coving was, and the plaster was not smooth.

There was no sign that the surface had been scored.

The tiles were quite large i.e. 33 x 25 cm, white ceramic Forme Alpe.

keystone

har0ld wrote: »

As a general rule you would expect fresh plaster to have been primed with something like PVA (usually 5:1 ratio with water) before tiling - most adhesives will be fine on this.

ARRRRGH! No, no and thrice no, Only prime with PVA if you want the tiles on the floor later. If primer needed use an acrylic one like Bal APD or Mapei Primer G.

Cheers

keystone

Leif

The problem that you have is that they lied, said they did but didn't and thats a key issue for you. White Star is white BTW. Topps Rapidset will be badged "someone elses" Usually its grey but can also come in white.

They are actually correct though, White Star (which is a very good tubbed addy) is self priming on anything other than highly polished surfaces when I would certainly advocate an acrylic primer first. The balance of probability is that, knowing it was to be tiled then the spread would not have polished the surface but just left it smooth. It would not have needed scoring if the adhesive was properly applied to the walls.

Don't forget that the wording on the tub and those uttered by CS will ALWAYS err on the cautious side and certainly be directed towards a CYA position.

IIRC you also had a problem with the adhesive not being properly applied leaving voids? Thats called incompetance although 80% contact is sufficient.

Didn't realise your tiles were that big. I would have used bagged rather than tubbed on the lot.

Cheers

cddc

Kesystone is correct. The colour of the adhesive is probably immaterial to your case really here.

Unless....... they have are claiming they have used White Star when what they have actually done is used a bagged powder adhesive without priming with one of the products Keystone has mentioned.

Either way they are at fault. It is either poor application of a (very good) tubbed addy, or improper priming, or failiure to prime whan using a powdered.

Topps rapidset is sold in both grey and white. If it is grey, this is for sure what they have used and not White Star. If they have used a grey powdered adhesive with white wall tiles and grout they are even bigger idiots.

Leif

They used two adhesives on the walls, and one on the floor. I found an old White Star tub and a Topps paper bag. Unfortunately I think the new installers threw them away, unless I can find them. I checked the packages, and the paper one certainly said to use primer. But without a copy, that is my word only. It looks like Topps Trade Rapidset adhesive has been discontinued.

Some of the tiles show adhesive to wall contact of about 20%. I have kept some for evidence. The three surveys say tiles almost fell off.

"The problem that you have is that they lied, said they did but didn't and thats a key issue for you."

Yes, I have shown they lied, which will help.

The court document will be fun as there will be a 3 page summary with numbered references to evidence consisting of copies of 5 or 6 letters, three surveys, 6 or 7 colour A4 photographs, and some large white ceramic tiles with adhesive on the back.

Leif

For what it's worth, I found out that Topps Trade Rapidset adhesive is still being sold, and on porous surfaces it needs primer. And it is white, or grey. Sorted!

andyhop

Leif wrote: »

For what it's worth, I found out that Topps Trade Rapidset adhesive is still being sold, and on porous surfaces it needs primer. And it is white, or grey. Sorted!

Any rapid set adhesive (which are all cement based) require primer when fitted to plaster walls

Lime(from the cement) and gypsum can form ettringate crystals which lead to a explosive reaction between the 2 substrates, Tiles will pop off and could cause injury