Adhesive / Preparation Confusion

[oldguy]

I am Fitting Large format Porcelain tiles in a bathroom. I have observed Kg / m etc, for plaster / plasterboard.

On skimmed plasterborad I understand I should use Bal APD primer, Bal wall & Professional cementous powder with Admix 1 , and a thick bed semi circular trowel.

On plaster board unskimmed - Is it same as above?

On painted plaster - paint is a bathroom wipeable paint so isn't flaky etc - I've sanded the wall lightly, and scored it thro' to the plaster skim - Can I use the same adhesive? Or do i need to use a pre mix on painted surfaces?

Any advise apprecaitted

thanks

 

[Richard C]

I am Fitting Large format Porcelain tiles in a bathroom. I have observed Kg / m etc, for plaster / plasterboard.

What size & thickness are the tiles? The weight must include up to 4 kg/sqm for the adhesive/grout.

Some but not all porc tiles need sealing before laying; some come pre-seled & some require sealing, do you know which type do you have? What colour are they?

On skimmed plasterborad I understand I should use Bal APD primer,

You can use any Acrylic primer but usually best to stick to same manufacturer.

Bal wall & Professional cementous powder with Admix 1.

Rather than add AD1 to the Professional, personally I’d use Rapidflex or Single Part Flexible. Use Microflex grout.

and a thick bed semi circular trowel.

If the tile base is really nice & flat (new boards), with all but the largest of tiles your probably OK to use a thin bed solid bed trowel on walls. A thick bed trowel will be OK, you will just use more adhesive.

On plaster board unskimmed - Is it same as above?

Yes

On painted plaster - paint is a bathroom wipeable paint so isn't flaky etc - I've sanded the wall lightly, and scored it thro' to the plaster skim - Can I use the same adhesive? Or do i need to use a pre mix on painted surfaces?

Use the same addy; might be advisable to use Bond SBR as a primer on paint surfaces other than non vinyl emulsion.

If by pre-mix you mean tub mix, a definate NO. Never use tub pre-mix on tiles much larger than 250mm x 250mm, it relies on evaporation to set & not suitable for large/heavy tiles. It will take an age to set, your tiles will be all over the place & in some cases it wont set at all & you’ll have to take them off & start again.

Are you tiling the floor?

 

[oldguy]

Tiles are 17.2kg per sq m. 600x400mm, 7.5mm thick, So I'm actually at 21kgs!!!, so i probably must use a thin bed 6mm round trowel ??? (I was going to risk the over weight...on the skimmed plaster and paint area's)
Tiles are glazed porcelain, but i can't find any information if they require sealing. They are travertine effect
I rang BAL and since i can't get hold of the Admix, they suggest i use single part, actually works out cheaper than the professional + admix.
The tile base is nice and flat.

thanks for the help

 

[Richard C]

Tiles are 17.2kg per sq m. 600x400mm, 7.5mm thick, So I'm actually at 21kgs!!!, so i probably must use a thin bed 6mm round trowel ??? (I was going to risk the over weight...on the skimmed plaster and paint area's)

There is almost certainly a safety margin in the published figures & my guess it’s at least 10% but I can’t say for certain. If the plaster is sound & in good condition (no hollow noises when tapped) you should be OK but no guarantees!

Tiles are glazed porcelain, but i can't find any information if they require sealing. They are travertine effect

If it’s glazed, it doesn’t need sealing.