Discuss question about mesh v's ditra in the The Welcome Forum area at TilersForums. USA and UK Tiling Forum

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Rina Rowe

We are doing an extension to our home and planned to tile the whole ground floor. We are using large 80 x80 porcelain tiles. On our spec, it specifies for the builder to use ditra mat under tiles. We have floorboards covered with OSB. The builder has now started tiling using reinforcement fibreglass mesh Reinforcement fibreglass mesh for waterproofing under tiling on terraces, waterproof under tiling on bathroom walls and floors - Reinforcement mesh - http://www.arcane-industries.co.uk/p246_r2676-reinforcement-fibreglass-mesh-for-waterproofing-under-tiling-on-terraces-waterproof-under-tiling-on-bathroom-walls-and-floors.html. He has promised us that it is just as good, if not even better than ditra mat. I have no idea whether to believe him or not as its cheaper and easier to lay the mesh. Can anyone please advise.??
Thanks so much
 
OP
J

J Sid

Ditra is an uncoulping membrane, what he is using is not.
if the spec says us ditra why let him use something else? and why is a builder doing tiling?
looks like his trying to save himself a few pounds.
 
OP
B

Blunt Tool

Welcome to the forum :) personally would never dream of tiling onto osb boards especially not on floors! Also had a look at mesh thing he is using and would not go near it! Ditra mat is the way to go, and osb boards up and tile insulation or tile backer boards down first glued and screwed
 
OP
F

Flintstone

In America they put ditra over osb, over here tho it is not common practice. As said, the mesh is no good, better to get that and the osb up before it gets too far, what sort of area has he stuck down ? Is he a tiler that the builder has got in or is it the builder himself doing the tiling ?
 
OP
I

Italy

Here in italy, terraces are all done so.
The expense is the same, more or less.
It costs less the product it is using but needs more labor.
The mesh on the walls is never laid, the bandles are enough.
 
OP
D

Dumbo

In America they put ditra over osb, over here tho it is not common practice. As said, the mesh is no good, better to get that and the osb up before it gets too far, what sort of area has he stuck down ? Is he a tiler that the builder has got in or is it the builder himself doing the tiling ?
Let me get this straight you are saying they use Osb not wpb ply in America to tile on ?
 
OP
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Rina Rowe

Thanks everyone. The builder has bought in a tiler. So just to clarify if I manage to get him to use ditra mat it shouldnt go on top of OSB. (It has been nailed down.)
 
OP
J

J Sid

OSB will be ok but not the best choice.
Ditra should be fixed with Ardex AF200 then tiled.
 
OP
R

Rina Rowe

Our spec specified 'Hard board floor to be fitted above floor boards', entire floor to be covered with ditra mat before tiling.' Is hard board so different to OSB? I am not sure what grade OSB is. Im going to ask the builder. Photo on the way!
 
OP
R

Rina Rowe

IMG_3785.JPG Photo of mesh on osb
 
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F

Flintstone

Is that tile stuck down ?
I wonder if hard board is a generic term for over boarding
 
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R

Rina Rowe

YES they have already stuck down about 10 tiles. OSB is 18mm thick. B & Q website write about it stating.....
OSB is a versatile and durable building board. It’s construction is similar to that of Plywood, with opposing-orientation of wood fibres that creates rigidity and strength. OSB has superb load-bearing properties, excellent cross dimensional stability and an attractive wood patterned finish.

  • Suitable for wall sheathing, flooring, roofing, general construction and rennovation work, formwork and long term site hoardings.
  • Load bearing/structural board for use in humid conditions.
 
OP
F

Flintstone

Can you put some more photos up, the reason I ask is, if doesn't look like floor boards, and there's no adhesive showing under that tile.
 
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B

Blunt Tool

YES they have already stuck down about 10 tiles. OSB is 18mm thick. B & Q website write about it stating.....
OSB is a versatile and durable building board. It’s construction is similar to that of Plywood, with opposing-orientation of wood fibres that creates rigidity and strength. OSB has superb load-bearing properties, excellent cross dimensional stability and an attractive wood patterned finish.

  • Suitable for wall sheathing, flooring, roofing, general construction and rennovation work, formwork and long term site hoardings.
  • Load bearing/structural board for use in humid conditions.
Please don't start trying to justify builders work, we are trying to help so that it doesn't look nice for a few month then all cracked and lifted after. The more information and photos you can give us the more we can help :)
 
OP
R

Rina Rowe

Sorry I am definitely not trying to justify the builders work. I am just quoting from b and q website to provide more details on osb. Thanks so much for trying to help!
I don't have more photos tonight, can get more tomorrow. There is grey flexible adhesive under that tile, builder says he is using extra adhesive because of mesh. Thanks so much for all the comments and help so far!
 
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B

Blunt Tool

Sorry I am definitely not trying to justify the builders work. I am just quoting from b and q website to provide more details on osb. Thanks so much for trying to help!
I don't have more photos tonight, can get more tomorrow. There is grey flexible adhesive under that tile, builder says he is using extra adhesive because of mesh. Thanks so much for all the comments and help so far!
Would advise stop all works on tiling and boarding till sorted out!
 
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Old Mod

I can't quote BS 5385, but to the best of my knowledge, osb/sterling board is not a suitable material to tile to, for that matter, no timber is.
It is too susceptible to external forces like heat/cold and moisture, even more so with a particle board.
And I certainly wouldn't swear by any technical description from B&Q/Trade-Point web site. They are two of the worst sites imaginable.
If your architect has spec'd 'Hardboard' technically that is also incorrect.
It would depend on his definition, it's ambiguous at best.
There are so many better options out there.
And tbh, if this mesh is as good or better than Ditra 25, why aren't we all using it?
Yes in certain circumstances it can add stability to a surface, but it is NOT a decoupling membrane, as was stated on your spec.
 

John Benton

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I've seen quite a few failures tiling onto OSB along with other types of timber. Agree completely with Antonio after looking at the accompanying video, maybe cheaper for the material but it's certainly more labour intensive, also not a decoupler. I would steer well clear!!!
 

GAZ5518

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IMO....OSB Board is primaraly used for flat roofs or sheds which are felted etc afterwards...not really a suitable substrate for tiling on.... But if you are accepting the B&Q description ... Then you absolutely should screw it down..6" centres ..... Over laying with a de coupling Mat as described before( Ditra, Bal...etc)
Your architect should be aware of the correct products ... and procedures... (as should your builder).....although he/she stating "Hardboard" would concern me..
Don't proceed and take heed of all the advice that is available to you on this site ..... It will save you Money and stress in the long run ....Hope all goes well...:sunglasses:
 

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