Unsuitable walls

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Unsuitable walls

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R

Rickm34

Hi there. So i have a job coming up. 5 fully tiled bathrooms. Glazed Porcelain tiles 300 x 600. First bathroom is 'ready'. Went to price it up. Tiles are a discount lot. 2 batch numbers which isnt a problem, but no box weight. So 2 walls in the first bathroom are skimmed plaster on pb. ( in my opinion tiles way too heavy for skim)I manage to stop them doing anymore. The remaining walls are bare pb, and bare pb in the other bathrooms.

Im using tilemaster extrabond standard set on walls
And tilemaster setaflex rapid on floors
Tilmaster grout 3000 grey flexi
And tilemaster prime plus

So i informed the builder who was oblivious to weight issue, and said it will be reet tiles wont fall off.

Im not happy about the 2 walls but he is adamant it will be fine.

I was planning on producing a waiver that the builder could sign that i have informed him of weight issues but that the builder is happy to proceed. How much weight will this hold, if you excuse the pun.



Anyone every done something like this?

Also in regards to the primer would you prime the plaster skim?
 
L

LM

Rickm34 said:
Hi there. So i have a job coming up. 5 fully tiled bathrooms. Glazed Porcelain tiles 300 x 600. First bathroom is 'ready'. Went to price it up. Tiles are a discount lot. 2 batch numbers which isnt a problem, but no box weight. So 2 walls in the first bathroom are skimmed plaster on pb. ( in my opinion tiles way too heavy for skim)I manage to stop them doing anymore. The remaining walls are bare pb, and bare pb in the other bathrooms.

Im using tilemaster extrabond standard set on walls
And tilemaster setaflex rapid on floors
Tilmaster grout 3000 grey flexi
And tilemaster prime plus

So i informed the builder who was oblivious to weight issue, and said it will be reet tiles wont fall off.

Im not happy about the 2 walls but he is adamant it will be fine.

I was planning on producing a waiver that the builder could sign that i have informed him of weight issues but that the builder is happy to proceed. How much weight will this hold, if you excuse the pun.



Anyone every done something like this?

Also in regards to the primer would you prime the plaster skim?
Click to expand...
Skimmed plaster can only hold 20kg per square metre, it's one of the worst substrates to tile on and yes it must be primed with two coats of an acrylic primer, never ever use PVA.
Plasterboard can take 32kg per metre squared, also prime.
Would it be possible to over board the skimwd walls with some mechanically fixed backer board or at worst plasterboard?
The waiver wouldn't be worth the paper it's written on here, fundamentally you are responsible because you know you should not be tiling on a substrate that can't take the weight. You'd loose in court.
 
R

Rickm34

LEE MAC said:
Skimmed plaster can only hold 20kg per square metre, it's one of the worst substrates to tile on and yes it must be primed with two coats of an acrylic primer, never ever use PVA.
Plasterboard can take 32kg per metre squared, also prime.
Would it be possible to over board the skimwd walls with some mechanically fixed backer board or at worst plasterboard?
The waiver wouldn't be worth the paper it's written on here, fundamentally you are responsible because you know you should not be tiling on a substrate that can't take the weight. You'd loose in court.
Click to expand...

Thanks for your reply. This could be one method as it is just at a shell stage. Or they might have to reboard the original. As the waiver is useless i wont be tiling it until its right.

In regards to the primer, im using the tilemaster prime, as i like to use all the same product. I never used wood glue.
 
O

Old Mod

The tiles will weigh approx 24kg per m2
Adhesive has an average weight of 1.5-2kg per mm per m2
As a 10mm trowel will give approximately a 3mm solid bed, this equates to somewhere between 4.5-6kg per m2 depending adhesive.
So you would be looking at a combined weight of approximately 28.5 - 30kg per m2.
This is for guidance only, but should be somewhere near the mark.
 
R

Rickm34

3_fall said:
The tiles will weigh approx 24kg per m2
Adhesive has an average weight of 1.5-2kg per mm per m2
As a 10mm trowel will give approximately a 3mm solid bed, this equates to somewhere between 4.5-6kg per m2 depending adhesive.
So you would be looking at a combined weight of approximately 28.5 - 30kg per m2.
This is for guidance only, but should be somewhere near the mark.
Click to expand...
Ok cheers i will bare that in mind. Might just take the bathroom scales lol
 
K

Kevbos

Omg all those skimmed walls I've tiled on for reputable tiling companies and builders over the years and now I find out its a weak substrate ?? Isn't this what we are asked to tile on .is say if worried advise them of your worries .because it won't be the adhesive that comes away from plaster .it will be plaster coming away from wall .and I have never had a problem with properly skimmed walls .that were primed and skimmed properly .it's what they are skimming over that's the problem .dusty .unprinted. wet .painted .etc etc .or weak walls

If you skim over a 3 in 1 mix sand and cement render for instance .try getting that plaster off .!

Lol sorry I just re read your post .pb meaning ply board ?? Sorry everyone was right at no instance do you tile over skimmed wood .forget weight issues .the likely hood of it ever working and holding are remote especially in new work .as soon as they turn heating on the ply shrinks plaster does nt they separate .if that was a floor .I'd be using a matting to cover ply wood to stop the expansion and contraction .noone skims floors !!
 
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R

Rickm34

timeless john said:
How long have the 2 walls been skimmed- need 3 weeks before tiling.
Your right to be wary of the weights and we've all been there. On a job of this size I know what I'd have done!
Click to expand...
Rebiard
Kevbos said:
Lol sorry I just re read your post .pb meaning ply board ?? Sorry everyone was right at no instance do you tile over skimmed wood .forget weight issues .the likely hood of it ever working and holding are remote especially in new work .as soon as they turn heating on the ply shrinks plaster does nt they separate .if that was a floor .I'd be using a matting to cover ply wood to stop the expansion and contraction .noone skims floors !!
Click to expand...
Its plasterboard
 
K

Kevbos

Sand and cement tile fixing is also best .but we don't live in world where we can do the best way of tiling anymore lol .

I don't see problem with tiling on skimmed plasterboard it depends how it is fixed and what strength it has .and how they prepping and skimming it .why not just not skim it even

Go on the tiling association website .says 20kg max skimmed plaster .36kg unskimmed. Better just let them board it and not skim .
 
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