about to tile bathroom but questions about BAL and surface

[happyhero]

Hi I am soon to tile the bathroom and pulling the old tiles off, which seemed to be held on with about 1cm of render type stuff, has left the walls all over the place, so I was going to use bonding plaster to get a flat surface again, ie one wall has those grey crumbly breeze blocks, the other surfaces have a sort of render finish on the blocks that make up the wall.

As the surface is to be tiled do I really need finish plaster on top of the bonding plaster?

Will the adhesive stick ok to the bonding or do I need to do anything to it?

I have heard a lot about how good BAL products are and the one you buy in bags and mix yourself.

Is the the self mix adhesive a lot better than the ready mix BAL which I could buy cheap from Screwfix?

Is the self mix Bal one easy to use?

Also what size trowel should I use, I keep seeing the 6mm one being mentioned?

Any help appreciated.

 

[daddym]

Hi I am soon to tile the bathroom and pulling the old tiles off, which seemed to be held on with about 1cm of render type stuff, has left the walls all over the place, so I was going to use bonding plaster to get a flat surface again, ie one wall has those grey crumbly breeze blocks, the other surfaces have a sort of render finish on the blocks that make up the wall.

As the surface is to be tiled do I really need finish plaster on top of the bonding plaster?

A) NOPE - I'd also strongly recommend using browning rather than bonding. "Crumbly breeze blocks" have a habit of soaking moisture up very well - browning plaster is designed for backgrounds with moderate suction, bonding plaster on the other hand will dry off way too quickly and will look like crazy paving. PVA the walls with a 1 part pva to 5 parts water mix before plastering and allow to dry out. Alternatively you could dry line with plasterboard or if a wet area, hardibacker boards?

Will the adhesive stick ok to the bonding or do I need to do anything to it?

A) It depends on the adhesive - I prime everything just in case. Use a proper primer such as BalPrime

I have heard a lot about how good BAL products are and the one you buy in bags and mix yourself.

Is the the self mix adhesive a lot better than the ready mix BAL which I could buy cheap from Screwfix?

A) Which self-mix (powdered) are you referring to, and what are your tiles made from?

Is the self mix Bal one easy to use?

A) Depends which one. Anything with the words "rapid set" are best avoided by DIYers.

Also what size trowel should I use, I keep seeing the 6mm one being mentioned?

A) What size tiles are you going to fix?

Any help appreciated.

 

[happyhero]

Cheers for the advice daddym.

I was tempted to plaster the walls to a straight surface when I was going to use bonding plaster as I have done quite a good job in the past using this but I am not a plasterer and have had some doubts as to whether I should really be calling a professional plasterer in.

I cannot really use any kind of board for many reasons in this room.

Is the browning coat ideal for tiling or would you rather bond and finish it or something else, because if it should really be bonded and finished I think I will most likely call in a plasterer?

Basically what is the best surface for tiling?

 

[happyhero]

just trying to think this through, if i did find a way to board the room up which would you go for, the moisture resistant plasterboard and would you definitely need hardibacker board in the shower area?

How would you stick these 2 types of boards to the wall, ie what do you use as the adhesive and many dabs per 8' x 4' sheet, say a dab every foot, would that be ok? Apologies if I am asking basics here.

The reason I am rethinking this is that 4 to 6 weeks sounds painfull, without a bathroom plus the time to then do the tiling and fitting stuff etc.

 

[gcol]

You don't tile onto bonding or browning - a finish coat is essential.

 

[happyhero]

If I choose dot and dab method what size boards can I use, ie do I have to use 15mm or is it ok to use 12.5mm?

 

[gcol]

12.5mm is fine. I'd use plasterboard then tank it for a guaranteed waterPROOF surface on which to tile.