Help!: Slate on 3mm Ply

[JJWTiling]

Dear All
My first post here and i am looking for advice.
The Customer has bought slate and is looking to to tile his kitchen. The builders have laid 3mm ply for me to tile onto. The ply has been tacked down very well. I was wondering if the ply is thick enough to tile onto. The slate varies in sizes from 600mm to 200mm and is 15mm thick.
Generally i would tile onto ply of thickness 9mm.
Would i still bond the floor with sbr?
Any advice welcome.
Many thanks
JJW Tiling

[wetdec]

re-nail it every 150mm in both directions or it will de-laminate on you with the moisture.

Why have they been so kind what they hiding ............


..

[Dave]

What sub-floor is the ply fixed to ..? and what adhesive you using..?

[JJWTiling]

Many Thanks WetDec
I will nail it some more to be on the safe side.
I like your humour, they seem decent folk.......

[JJWTiling]

The sub floor is wooden, The customer is supplying all the materials including sealar for the slate. I havent got the job yet, so i am unsure to what they have bought.
It has to be a flexible adhesive, yes.

[Dave]

That thickness of ply overlay is no good for normal flexi cement adhesive......depending on the quality/ grading of the slate you will need thickbed adhesive as well....so 2 part is out of the question on thin ply for slate.....most standard adhesives will bed to 6mm and if thicker is needed for rough graded slate then a thickbed adhesive is used...

[Sir Ramic]

No way would i tile onto 3mm ply and i never use nails. This sounds like a disaster waiting to happen IMO.

[JJWTiling]

3mm does seem rather thin, It should be screwed down rather than tacked. I will see if he contacts me tmw. If it sounds like a disaster I'd rather not take it on.
Many thanks

[Sir Ramic]

i would feel a lot safer with backer board at 6mm glued and screwed or a thicker ply. 15mm is the recommended thickness by most adhesive manufacturers.

[JJWTiling]

Would you recommend an adhesive i could use.
Would Ardex s20w rapid thickbed adhesive be any good?

[monty]

3mm does seem rather thin, It should be screwed down rather than tacked. I will see if he contacts me tmw. If it sounds like a disaster I'd rather not take it on.
Many thanks

Wouldn't the ply split if screwed down with being so thin...I'd much prefer to tile onto 6mm backerboard......And as for adhesive i think BAL Ptb will be fine (assuming floor is sound underneath)

[Dave]

Would you recommend an adhesive i could use.
Would Ardex s20w rapid thickbed adhesive be any good?

NO its not suitable for timber......


Use ardex 7001 if ardex is your prefered choice...but you need a thicker sub-floor...imo

[pjtiler]

go over it with 9 mm/12mm ply screwed every 200mm

[Daveyboy]

I don't like tiling on to ply laid by someone else as I can't guarrantee the boards have been properly secured and I wouldn't like to tile on a 3mm ply, can't see it adding much rigidity/strength to the existing floor.. I wouldn't like to nail/screw it either in case I hit a water/gas pipe that might be lurking right under the floorboard. I'd be very cautious JJ

[kilty55]

i agree with that im not keen on tiling onto customer laid ply,last job was this and i asvised them they should screw it down,,,,he said its okay mate we used a hilti nail gun with 5 inch nails its solid amazingly they never hit any pipes

[chrisroe]

no chance i wood not do it

sorry for the pun

15mm min prefer 25mm then schluter dural matting then spf

[Fred]

Dear All
My first post here and i am looking for advice.
The Customer has bought slate and is looking to to tile his kitchen. The builders have laid 3mm ply for me to tile onto. The ply has been tacked down very well. I was wondering if the ply is thick enough to tile onto. The slate varies in sizes from 600mm to 200mm and is 15mm thick.
Generally i would tile onto ply of thickness 9mm.
Would i still bond the floor with sbr?
Any advice welcome.
Many thanks
JJW Tiling

Theres that song, how does it go, oh yes, ..................I said no no no......................

3mm ply tacked down, do these builders really know what they are doing..................

I was sucked in by this builder who tacked down the same and I insisted on 12mm ply screwed every 6 inches. Several months later, the client called me saying tiles were cracking, and it cost me money and a days work.

[GazTech]

Wouldn't the ply split if screwed down with being so thin...I'd much prefer to tile onto 6mm backerboard......And as for adhesive i think BAL Ptb will be fine

No it wont be fine.Minimum 15mm ply screwed at 30mm centres. Otherwise its fastflex, if floor is sound enough for it....Gaz

[wetdec]

Well thats me well and truelly told for working on the asumption the ply is in fact 6mm as you dont see 4,5 or 3,5 that oftern its ususlly on order. Any way I cocked up and if it is in fact 3mm you would be better beefing it up a bit more to make sure its sound enough to fix on.

My bad

tiler

[brian c]

go over it with 9 mm/12mm ply screwed every 200mm

exactly what i would do.

[mickbull]

Sounds like there covering something up to me. 3mm ply,they may as well have just used hardboard!! I'd re-ply for sure, at least 12mm, better safe then sorry.

[monty]

No it wont be fine.Minimum 15mm ply screwed at 30mm centres. Otherwise its fastflex, if floor is sound enough for it....Gaz

Sorry Gaz should have put once floor made sound!

[medlar]

personally i would overlay the existing ply with 12mm ply screwed every 200mm,and yes mate i would use SBR as well and my choice of adhesive would also be fastflex

[pjc]

the ply is not suitable to tile far to thin it will delaminate it needs to be removed is it floorboards underneath ? :Pete

[GazTech]

personally i would overlay the existing ply with 12mm ply screwed every 200mm,and yes mate i would use SBR as well and my choice of adhesive would also be fastflex

SBR for the back and the sides of the ply, with fastflex on suitable ply, no need to prime the surface....Gaz

[JJWTiling]

I think he said it was just floor boards underneath. He hasnt got back to me yet so i cant confirm.

[JJWTiling]

Thank you
appreciate the advice

[GazTech]

I think he said it was just floor boards underneath. He hasnt got back to me yet so i cant confirm.

I wouldn't be happy JJW, I would want to investigate the sub-floor before I gave a professional opinion on how prepare best for this job, and with which materials will be best suited.....Gaz

[JJWTiling]

Cheers Gaz
I will let you know what the sub floor is, when i find out

[andersontiling]

i would remove the ply and replace with 9mm -12mm ply screwed every 150mm centres and use a flex adhesive and grout.on a 3mm ply floor if you used a high spec adhesive you would end up with stress cracks in the slate plus 7001 and fastflex is no good for bedding up.doesnt matter how much you screw the 3mm down you will always get parts of the board raisng where the screws arent like a ripple effect...in my opinion