Advice on travertine floor

[The D]

i will also add to this thread
The use of sheets and boards that are subject to movement from changes in moisture content, e.g. wood-based materials such as plywood, chipboard, wood particle boards, etc. should be avoided if at all possible. If such boards have to be used they should be restricted to small areas and tiles should not bridge joints between boards. It is good practice to seal all exposed edges and the backs, but not the faces, of such boards with a suitable sealer to prevent distortion by atmospheric humidity changes. Care should be taken to ensure such boards are not installed in a condition where their moisture content is higher than the ambient equilibrium moisture content once the tiled installation is in use. Failure to observe this can lead to subsequent warping and distortion of the boards with consequent cracking and delamination of the tiling.

 

[diamondtiling]

Ditra stuck down with flexible adhesive straight onto the floor boards (prime floor first), economical and easy to lay. UFH onto the Ditra (I stick mine with spray carpet glue) Fill the whole lot with 2 part laytex SLC. Tile using Flexible adhesive and flexible grout (I think Ditra guide says you don't need flexi, but I use it all the same.). No need to seal tiles before any of this unless using a dark coloured grout. If you seal before grouting it actually stops the grout keying to the holes in the Travertine.
I have found over the years that Ditra is by far the best product for movement, I have used it on uneven floor boards, ones that aren't nailed down, even traveresed missing boards, and never had any problems.
There is no point putting an expansion joint in unless it is at a point where the joint runs right through the whole floor, like where the joining of 2 peices ply would be needed in the door, but Ditra gets over this so no joints needed at all, just expansion around the edges.

Are you serious? That has to be some of the worst advice I have ever read, Have you ever heard of BS standards? No manufacturer on the planet would agree to honour any guarantee if they inspected an installation such as you specify.

 

[Alberta Stone]

i will also add to this thread
The use of sheets and boards that are subject to movement from changes in moisture content, e.g. wood-based materials such as plywood, chipboard, wood particle boards, etc. should be avoided if at all possible. If such boards have to be used they should be restricted to small areas and tiles should not bridge joints between boards. It is good practice to seal all exposed edges and the backs, but not the faces, of such boards with a suitable sealer to prevent distortion by atmospheric humidity changes. Care should be taken to ensure such boards are not installed in a condition where their moisture content is higher than the ambient equilibrium moisture content once the tiled installation is in use. Failure to observe this can lead to subsequent warping and distortion of the boards with consequent cracking and delamination of the tiling.

That material is industry standard and only on upgraded jobs will you ever find a sheet of plywood in western Canada, the builders all use chipboard, which is then sheathed with 3/8th inch exterior grade ply and we are expected to tile over that...that is the everyday reality of the jobsite.
You can tell them that they need some cement board laid over that and they whine about the added cost, and the height issues which will require them to add a layer of material throughout the rest of the job.
Every spec I have read has said that cement board is NOT structural and so to achieve the 1-1/8th inch minimum thickness of 2 layers of wood you then need another layer of the cementitious board (another 1/2 inch)
So now there is 1-5/8 inch deck upon which another 1/2 inch of tile and mortar goes bringing the total height to 2-1/8th inch which is quite the step up.
So if one has to match up to the level of 3/4 inch hardwood which they just nail onto the chipboard primary there would be a 1-3/8 inch difference.
This has been a constant issue in the day to day here which ditra helps to absolve as I will lay the ditra over the 1-1/8 inch layers of subfloor and then tile which results in very little height difference.

I haven't laid much cement board in years as a result.

Even large, multi million dollar homes are built by the builders this way as a matter of course. Mostly OSB homes here...they use that...um...stuff... for everything these days, even joists and beams.

 

[teo]

Thanks for the answers.
Everything make sense to me now (to an expert would have made sense ages ago :lol.
So the procedure is: prime last layer of ply with sbr (should i prime even the top side to stop the moisture from the screed to warp the ply?), ufh, 2 part latex leveling compound, wait until completely dry, prime with sbr again, flexi adhesive (2 part or single part?)with a 4mm square notched trowel (should be enough since the level compound will be flat) then bed the ditra mat into it (pressing firmly, checking for coverage), then flexi adhesive (again 2 part or single? i would say 2 part) with a 10 mm half moon trowel, then bed the tiles (after back buttering)onto that as usual (i would love spacing to be 2mm as i dont like big grout lines..).
I was wondering how much height over the level compound all of that would add:4mm(ditra+adhesive), and then 18mm(12mm tiles plus the bed of adhesive that when pressed down will probably be 6mm), total 22/22 mm.
Are my calculations correct?
Sorry for asking so many questions..

 

[Alberta Stone]

to achieve the 1-1/8th inch minimum thickness of 2 layers of wood you then need another layer of the cementitious board (another 1/2 inch)
So now there is 1-5/8 inch deck upon which another 1/2 inch of tile and mortar goes bringing the total height to 2-1/8th inch which is quite the step up.
So if one has to match up to the level of 3/4 inch hardwood which they just nail onto the chipboard primary there would be a 1-3/8 inch difference.
This has been a constant issue in the day to day here which ditra helps to absolve as I will lay the ditra over the 1-1/8 inch layers of subfloor and then tile which results in very little height difference.

My math wasn't functioning this morning (didn't have my coffee ) as I didn't account for the 3/4 inch primary deck, so the difference would be 5/8 inch which is still quite a bit of a speed bump.
So ditra is a great addition to the trade as most builders and clients just will not add extra money to the budget to make things level.

 

[The D]

That material is industry standard and only on upgraded jobs will you ever find a sheet of plywood in western Canada, the builders all use chipboard, which is then sheathed with 3/8th inch exterior grade ply and we are expected to tile over that...that is the everyday reality of the jobsite.
You can tell them that they need some cement board laid over that and they whine about the added cost, and the height issues which will require them to add a layer of material throughout the rest of the job.
Every spec I have read has said that cement board is NOT structural and so to achieve the 1-1/8th inch minimum thickness of 2 layers of wood you then need another layer of the cementitious board (another 1/2 inch)
So now there is 1-5/8 inch deck upon which another 1/2 inch of tile and mortar goes bringing the total height to 2-1/8th inch which is quite the step up.
So if one has to match up to the level of 3/4 inch hardwood which they just nail onto the chipboard primary there would be a 1-3/8 inch difference.
This has been a constant issue in the day to day here which ditra helps to absolve as I will lay the ditra over the 1-1/8 inch layers of subfloor and then tile which results in very little height difference.

I haven't laid much cement board in years as a result.

Even large, multi million dollar homes are built by the builders this way as a matter of course. Mostly OSB homes here...they use that...um...stuff... for everything these days, even joists and beams.

not my words m8 it is a quote from BS5385

 

[teo]

Got all the material here so i am ready to do it in a couple of weeks.
Is my step by step procedure the right one?
Also since i like small grout lines is 4 mm really required?(i was hoping to do it in 2 mm with mapei ultracolor plus grout).
Regarding the priming with sbr..is it better (just in case) to prime every time we have to bond a new material onto the existing one or is it overkill(like plywood before leveling compound and leveling compound before tile adhesive?)

 

[Alberta Stone]

not my words m8 it is a quote from BS5385

They (BSI) want to bill me 182 pounds for that info, 91 quid if I am a member, which is irrelevant over here.
We have a different set of building codes in North America.

So do they indicate what one should seal the boards with? Paint, silicone waterproofing sealant? or just no indication?

 

[teo]

Hello all.
Got all my materials and this week end i will start.
If i may ask for more advices before i start, i noticed while on a job that the people that were laying the screed had put some of that foam tape all around the rooms edges and where theres an expansion joint.
Do i have to do it even with latex compound? (it will be around 5 or 6 mm thick)
On the latex leveler its not explained if i have to prime it with sbr before laying the adhesive, i guess it will help with adhesion and drying time?
Also is 2 mm grout line ok? I like small lines with big tiles..
Thanks everyone.

 

[aytiling]

Ditra doesn't stop the need for an expansion joint. It would also need to be laid ontop of the UFH, as the idea is to uncouple the UFH from the tiles.

Ditra does indeed stop the need for an expansion joint, and no you lay the UFH on top of the Ditra as you would lose the efectivness of the mats if you laid it under, where do you get the idea that you are trying to uncouple the UFH to the tile?

 

[Gazzer]

Ditra does indeed stop the need for an expansion joint, and no you lay the UFH on top of the Ditra as you would lose the efectivness of the mats if you laid it under, where do you get the idea that you are trying to uncouple the UFH to the tile?

Note:
For radiant heated floors, we especially recommend our system Schlüter-BEKOTEC-THERM, the ceramic thermal comfort floor.
Schlüter-DITRA is also recommended for uncoupling of radiant heated floors consisting of thin electric heating mats. Schlüter-DITRA may be installed either above or below the heating mat. However, the uncoupling function is more effective if Schlüter-DITRA is installed above the heating mat.

Schlüter-DITRA - Schlüter-Systems

 

[aytiling]

Are you serious? That has to be some of the worst advice I have ever read, Have you ever heard of BS standards? No manufacturer on the planet would agree to honour any guarantee if they inspected an installation such as you specify.

No one asked you to act on my advice. I do what I have done for 35 years without a hitch. BTW go to Schluter and DK heating and ask them for the process of laying UFH with Ditra, because it was them that instructed us at Fired Earth to do it that way.

 

[aytiling]

Note:
For radiant heated floors, we especially recommend our system Schlüter-BEKOTEC-THERM, the ceramic thermal comfort floor.
Schlüter-DITRA is also recommended for uncoupling of radiant heated floors consisting of thin electric heating mats. Schlüter-DITRA may be installed either above or below the heating mat. However, the uncoupling function is more effective if Schlüter-DITRA is installed above the heating mat.

Schlüter-DITRA - Schlüter-Systems

Crikey that was quick!! That's funny because they told us that the heat generated by the heating mats underneath the Ditra might uncouple the mat from the Ditra, which would lead to hollows in the floor and also might actually MELT the Ditra!! And just say that there was a split in one of the heating wires, by sending a current though the system you can actually find the tile the split is under, uplift, repair and relay, you try doing that with matting on top of the whole thing

 

[Gazzer]

So what about wet heating systems ?? The mat has to go over the pipework....go figure.

How would it melt the Ditra ? either way its either under or above ?

 

[aytiling]

So what about wet heating systems ?? The mat has to go over the pipework....go figure.

How would it melt the Ditra ? either way its either under or above ?

Sure, agreed, but read my edit to the last post though. The melting quote was theirs not mine.