Advice on How To Prepare Sub Floor - TilersForums.com

[Cherie]

I put down I quess it would be the 18mm. But I didn't put in heating. I wanted it the husband did not

My floor had a diagonal planks on the joists then t&g planks. I put the 18mm ply down then Ditra. I put in large tile. Just trying to prevent cracking down the road.

 

[Dittybag]

My floor had a diagonal planks on the joists then t&g planks. I put the 18mm ply down then Ditra. I put in large tile. Just trying to prevent cracking down the road.

I did a kitchen floor remodel in a very tight space. The subfloor and underfloor joist had dry rot on the exterior beam ends. I had to demolish the subfloor, cut away the beam ends (after supporting the beams) and them install sister beams. ONce i had a solid foundation I installed tongue and groove subfloor with 3/4" sheet over it. I then install radiant heat from SunTouch and bedded than it with Levelquick. Schluter Ditra on top and then latge format ceramic tile on top. That was 10 years ago, NO cracks to this day and the radiant heat is a winter blessing.

 

[srosenbaum]

Hello all,

I am planning on tiling my bathroom floor, I removed the old tiles myself which were very poorly laid to say the least.

Once I got the 4mm plywood they had over boarded with, the floor boards were in a right state so I decided to replace them with new ones.

After doing some research I am a little lost as to how to proceed in terms on preparing the floor before tiling it.

I was going to overboard the floorboards with 12mm plywood & then use tile backer board on top of that as I am installing a heating mat but I see many people recommend using 18mm ply to make the floor even more rigid along with inserting noggins between the joists to make things even more solid.

To throw another spanner in the works I am unsure if I should be using a decoupling membrane like DITRA as I am laying tile on top of a suspended wooden floor.

So I thought I would ask here as I am a little lost on how to proceed.

What does concern me is that if I do need to lay 18mm ply & backer board the floor height is going to be a good 30mm higher which will cause problems for me at the door threshold to the landing.

I have included a few pictures of how the floor looks now.

Many thanks

Adam

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You can use the Prodeso system and put the wire right in the recessed channels in the membrane. The height of the membrane with wire is about 5.5mm. I have attached the Installation Manual, and the requirements are on Pages 6 & 7. Underlayment layers and thicknesses are called out on Page 7. The good thing about Prodeso is that you can use modified thinset to set the tiles above the membrane, as long as it meets the ANSI A118.11 spec. No need for 2 different types of thinset with that system.