preparing wall for tiling

[Perth]

Hi,
have read through the priming/tanking posts and think I've got it.
we have a new bathroom which has green plasterboard around the bath and a gypsum plaster skim over the top. we will have a shower going over the bath.

1. I rub the plaster down and wipe it to remove dust.

2. I paint the walls with a bonding coat - can you give me a specific product name. Is this different from a tanking kit.

3. I use a powdered adhesive which is waterproof and fill with a powdered waterproof grout - can you also suggest products.

4. do I only need to treat the wall with the bonding coat above bath level or should I do down to the ground given that the bath is not in place yet.

5. I have emulsioned walls already leaving area for tiles unemulsioned but guess there might be an overlap - whoops - do I score the emulsion and then put bonding coat over this area too.

6. what is the best way to seal the area of tiles along the top of the bath to stop water going down the side and should i just stuff tons of silicone around the area where the tiles will be cut to let waterpipes through wall to shower unit.

Many thanks for help - hubbie has left this job to me so want to get it right and tile shop told me normal plaster sealer/pva or nothing would do to treat wall which after reading doesn't seem correct.

 

[Softus]

1. I rub the plaster down and wipe it to remove dust.

Yes. Also remove any finish plaster that isn't firmly attached.

Are the walls also generally solid and not prone to wobble/movement?

2. I paint the walls with a bonding coat - can you give me a specific product name.

Bal - click here.

Is this different from a tanking kit.

Yes. Bal and Dunlop do good ones. I wouldn't normally use a tanking kit for a bath area, even if it's also a shower.

3. I use a powdered adhesive which is waterproof and fill with a powdered waterproof grout - can you also suggest products.

Bal, Nicholls and Clarke (aka Nicobond), Feb. Not Wickes or any other cheap sh*te.

4. do I only need to treat the wall with the bonding coat above bath level or should I do down to the ground given that the bath is not in place yet.

Er, only where you're tiling.

5. I have emulsioned walls already leaving area for tiles unemulsioned but guess there might be an overlap - whoops - do I score the emulsion and then put bonding coat over this area too.

Precisely. Get medieval on that non-porous surface!

6. what is the best way to seal the area of tiles along the top of the bath to stop water going down the side and should i just stuff tons of silicone around the area where the tiles will be cut to let waterpipes through wall to shower unit.

There are topics that cover this in detail (let me know if you can't find any), but the basic principle is:

1. Make the bath completely immovable; fix any loose flooring, screw down the feet, etc.
2. Leave a 2mm gap between bottom of tiles and top of bath rim.
3. After grouting, fill the bath with water, then silicone the 2mm gap and leave the bath full of water for at least 24 hours. Use the best quality sealant you can get your hands on. Dow Corning will do.

Many thanks for help - hubbie has left this job to me so want to get it right and tile shop told me normal plaster sealer/pva or nothing would do to treat wall which after reading doesn't seem correct.

I don't favour PVA in this scenario.

 

[Perth]

hey thanks for your quick reply

hopefully wall is even as it is newly plastering. if slightly uneven what size gaps along straight edge are acceptable?

so basically i need to prime the wall and then also tank it before adhesive - wasn't sure if priming was same as tanking.

and i don't need to prime and tank under the bath but only where i'm tiling. wasn't sure if it mattered if leak got own side of bath and wetted wall a bit - good to know i don't need to bother with that.

Many thanks

 

[Softus]

hopefully wall is even as it is newly plastering. if slightly uneven what size gaps along straight edge are acceptable?

That depends on the amount of unevenness and the size of the tiles.

so basically i need to prime the wall and then also tank it before adhesive - wasn't sure if priming was same as tanking.

Er, personally I wouldn't tank it, but it's up to you.

and i don't need to prime and tank under the bath but only where i'm tiling. wasn't sure if it mattered if leak got own side of bath and wetted wall a bit - good to know i don't need to bother with that.

If water got through the seal between bath and wall, then it's going to fall to the floor and leak downstairs - tanking the wall wouldn't stop this from happening.

 

[Perth]

oops - read your first reply as saying you would tank it! have now re-read it and see you said not to. good news.

have checked walls with a straight edge and alarmingly realise that the corner the bath will go in is not actually 90 deg! well it is for the first 2" and then it widens out. playing around with the square can prob put it in so it is out by 6/8ths at the width edge furthest from the corner. looked like length was going to be out furthest from corner too but wall has a dip in middle and a longer straight edge showed bath meeting wall again by the time it's full length was in place. bow in wall on length side is about 5mm.

1.What is best practice to deal with this bow on the length side.

2. what is best practice to deal with the 6/8ths difference along width - can i swallow this by putting extra adhesive on and running a beading or such down side of tiles and just have tons of shampoo bottles stacked on end of bath to hide unparallelness on bath as you look down on it!

guess there must be a profesional answer to this problem as how many corners are 90 deg.

many thanks.

 

[Softus]

have checked walls with a straight edge and alarmingly realise that the corner the bath will go in is not actually 90 deg! well it is for the first 2" and then it widens out. playing around with the square can prob put it in so it is out by 6/8ths at the width edge furthest from the corner. looked like length was going to be out furthest from corner too but wall has a dip in middle and a longer straight edge showed bath meeting wall again by the time it's full length was in place. bow in wall on length side is about 5mm.

Er, not quite sure what the upshot of all that was, but usually one can juggle things to minimise the gap all around the bath.

Poke the corner into the corner and make the gaps the same at the two corners that should be touching the wall. If the gap is still more than about 5mm, then consider digging the bath into the corner by whatever is needed. You can chip/chisel out plaster and/or plasterboard to achieve this.

I wouldn't ever use beading as a method of sealing, because it's sh*te.

 

[Perth]

cool didn't think of that - so where it's tight in the corner ie the 90 deg bit i just keep gouging until it moves in enough that the bath is touching at both outer ends and then tidy up gouges with filler or just rely on all the adhesive,etc filling in the rough gougy bits. Just as well I didn't take hacksaw and cut the bath to fit!
should one get with the bath or buy seperatley metal wall hangers or would a rebated 2x2 be sufficient to hang the bath?

cheers

 

[Softus]

should one get with the bath or buy seperatley metal wall hangers or would a rebated 2x2 be sufficient to hang the bath?

Get with. Usually.

What is the bath made of, and how thick is it? Does it have a wooden base and support frame?

 

[Perth]

Hi,
it is a kaldewei saniform plus metal bath 1500x700 from bathstore which doesn't seem to have come with any hanging brackets but has pretty sturdy feet to go on the bottom and as far as I can remember was a good thickness and not the tinny one.
was going to run a wooden baton along wall to lip bath over. bath does have 2 odd things sticking out of slope bit at back about 1/2 way down but came with no literature so not sure what these are for. Am also presently looking for an obvious earthing point.
Any experience of these baths?

Cheers

 

[bananaspark]

mount the bath on 2 x 4 wooden (seasoned and treated ) box frame, bolted to your joists and walls.
so if you kick it or sit/stand/jump on any corner of it it doesnt move,
to test this i use a spirit level with a laser, pointed at a far wall to see visibly any deflections in real world use.


b/