Advice on travertine floor

[teo]

Hello all.
I need some advice on laying my kitchen and dining room floor.
Since i got some good prices for travertine tiles (600*450) and underfloor heating(ufh)
i was wondering if i could do it myself;i am not a tiler expert as my trade is dry lining, but i have done quite a lot of ceramic tiling as well.
The area is around 50 smq, the substrate is wooden floorboards (with extra noggings to make it stronger).
I was thinking of, instead of taking boards up to lay a 6mm backerboard, lay underfloor heating onto the boards, then self leveling compound, then travertine tiles(sealed before laying and after grouting).
What i am not sure is how much screed is needed for covering the underfloor heating (is it enough if i just cover it few mm above?) and if i need an uncoupling membrane (like ditra) on top of the screed.
Also do i need expansion joints?( never done a big area before)
Was hoping to do it myself since i enjoy tiling.
Thanks in advance for any help.

 

[diamondtiling]

Hi Teo welcome to the forum.

The first thing that springs to mind are the floorboards, are they chipboard or planks? either way I would be removing and replacing with 18mm ply and then the 6mm backer boards. You need to get the floor sorted first before even thinking about the travertine or ufh.

 

[Gazzer]

UFH and Natural stone = uncoupling membrane, everytime.

 

[teo]

Thanks for quick reply!
They are planks, i think 18mm thick.
Floor seems quite stable already, so i thought i could save on ripping it up
So its best practice to replace it with ply?
i have always replaced boards with ply when doing the bit of tiling i have done, wasnt sure about this one.
i will see if i have extra money to replace with ply, screwed down as usual.
so the sequence is 18mm ply, 6mm cement board,underfloor heating, self level latex screed slightly above heating,ditra mat, then tiles (i was thinking about 3mm or 4 grout lines with mapei ultracolor plus).
seems quite a lot of work
gosh its a lot of work

 

[teo]

forgot to say floor is ground floor, joisted.dont know whats under joists as i havent ripped it up already, but i thought to put extra noggings anyway as precautions.
thanks

 

[teo]

my fingers are faster than my mind...forgot to ask if i could go away without expansion joints, since i would like a continuous look.

 

[Gazzer]

my fingers are faster than my mind...forgot to ask if i could go away without expansion joints, since i would like a continuous look.

That would depend on the maximum lengths but always have a perimeter expansion and in doorways. they are not intrusive if colour matched.

 

[Gazzer]

When replacing floors always make sure the 18mm (or thicker) ply is WBP and of good quality. Too much inferior ply out there at the moment and I cant see it ever getting any better.

 

[teo]

thanks for info.
about the expansion joint, since i was thinking about a brick effect does that means i have to do a "not straight" joint or just cut the tiles at the doorway? ( i guess the joint is done with colour matching silicon instead of grout).
Another question that spring to mind...if the wbp is 18 mm do i really need an extra 6mm of cement backerboard?
I was thinking since i already use the decoupling membrane as suggested and since i guess the backerboard is more for stability than strenghtening, do i really need it?
btw Area is quite big its a big kitchen with a small wall that divide the dining from the cooking area, so the joint will be quite long.

 

[diamondtiling]

The backerboard is to give you a tiling surface, its far better than ply which is there for strength, movement and stability although extra noggins are a must. Your expansion joint will be a straight one at doorways etc and will be colour coded with the grout.
The ditra is an extra backup for movement and de-coupling which always occurs but more so in wooden floors.
Correct prep at this stage is vital Teo.

 

[aytiling]

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.

 

[Matt]

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.

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.

 

[Alberta Stone]

Cement board is nice but it is not a structural material, merely a backer meaning it provides a smooth surface.

Over here the specs are 3/4 inch ply as primary deck glued to floor joists which have crossbracing.
followed by 3/8 inch exterior grade ply glued and screwed to primary.
Bonding agent applied to top sheath layer then the UFH cables are installed.
This is parged over with a flexible thinset, like versabond by Custom.
Once level and ready the Ditra mat is installed and the stone is installed onto that.
Solid and durable with no movement.

And for a small area like 500 sq ft then you should not need a control joint, but I have no pictures of the site so cannot say with certainty if that is correct in this case, but most likely.

 

[teo]

Wow lots of replies.
O today since i had time i lifted some floorboards to see whats underneath.
Before i said floorboards because i haven't looked properly ( i know...sorry for giving wrong informations!)
After lifting the now knackered vinyl i noticed that in the kitchen area theres 18 mm ply all screwed to the joists, the dining area is different, its floorboards 18 mm thick ( tongue and groove) more or less at the same level.
So i was thinking of overboarding with ply again to make everything level (or cement board..depending on prices)then lay the underfloor heating, 2 part latex leveling compound until everything disappear, then since theres a short wall (both sides) that divide the area, to put a movement joint there (its where theres the difference in substrate).
Still not sure about the membrane,since it will make quite a lot of difference in my budget, but if everyone think its necessary i will definitely get it.
I will plan to do it in 3 weeks time more or less..
Thanks everyone for the knowledge given!

 

[Alberta Stone]

Travartine is so fragile that I wouldn't think of putting it down without ditra.