Prep for Ditra

[Artisan Ceramic]

Hi all, some advice please. I am laying ditra matting on a very large concrete kitchen floor. Why? The builders had a go at self levelling the floor twice and made a right hash of it both times. Builders have now disappeared leaving the customer in a mess. The SLC is flaking in parts and the floor is still slightly uneven where they just threw the stuff down. I spoke to Mapei and have ascertained that there is a DPC and the floor isn't damp. Customer doesn't want another layer of SLC, so I thought I would take up any excess flaking material, use a SLC on a couple of parts where the level is a little low and then lay Ditra. My question is what is the best way of fixing the ditra. Should I use my normal ady, or should I use a thin set to fix it to the floor with. Can anyone forsee any other problems I may run into.

Thanks

Steve

 

[grumpygrouter]

I'm not 100% sure Ditra will be of any benefit in this situation. Why not just remove the flaky stuff, re-level where necessary as you are looking to do, then use a thick bed flexy adhesive like Keraflex Maxi to take up any deviation?

 

[peckers]

I agree with grumpy, Is there any other reason why you want to use ditra? this won't sort out the levels, remove all the flaky slc and then repair as grumpy has said...

 

[Artisan Ceramic]

I guess I am nervous about the extent of the flakiness. It's at its worst under the kitchen units. The tiles are large 60 x 60 porcelain. Customer was really adamant that they didn't want us to lay another SLC, but where the level is low, there is no choice. Being black glossy tiles the floor needs to be level and I thought the matting may be a solution as recommended by Topps. I am a little concerned that the Keraflex Maxi needs 24 hours before it can be walked on as this customer has kids. Do you still reckon this is the way to go?

Thanks for your help and advice mate.

 

[Time's Ran Out]

There is no way I'd be laying anything onto a flakey subfloor!

 

[peckers]

Ditra has its uses in many areas But covering up a bad substrate to start with ISNT one of them!
The previous builders have dropped a clanger on this one by messing up the job for your customer, tell your customer that the floor can not be tiled or covered up and tiled onto as its not suitable as it is.
Tell them that to have a good job done that the slc will have to be removed and reaplied properly!
and that 600x600 porcs need to be flat and the only way to achieve this is by re-doing the floor correctly.
You can hire a concrete planer from a hire shop which will make short work of this and then you can prime the floor and then re lay new slc.
If they want the job done properly and you explain the reasons then they should understand. if they dont want it done properly then let someone else do it.
after all its your reputation.

 

[Bazley]

sounds like hassle and if you tile it any later problems its down yo you dude. still if gonna do it try removing flaky bits.sdr and then slurry mix ontop and then stick wedi board ontop....level floor and then you can use a fast set adhesive

 

[Time's Ran Out]

sounds like hassle and if you tile it any later problems its down yo you dude. still if gonna do it try removing flaky bits.sdr and then slurry mix ontop and then stick wedi board ontop....level floor and then you can use a fast set adhesive

Are you sure this is a cost effective proceedure?
Large kitchen floor - wedi boards.

 

[The Legend; Phil Hobson RIP]

Ditra has its uses in many areas But covering up a bad substrate to start with ISNT one of them!
The previous builders have dropped a clanger on this one by messing up the job for your customer, tell your customer that the floor can not be tiled or covered up and tiled onto as its not suitable as it is.
Tell them that to have a good job done that the slc will have to be removed and reaplied properly!
and that 600x600 porcs need to be flat and the only way to achieve this is by re-doing the floor correctly.
You can hire a concrete planer from a hire shop which will make short work of this and then you can prime the floor and then re lay new slc.
If they want the job done properly and you explain the reasons then they should understand. if they dont want it done properly then let someone else do it.
after all its your reputation.

That is the option I would choose, start again, blank canvas. Do it right once

 

[Ken Bruty]

Defo with Peckers and Phil with this one, as the tiles will be very likely popping up in no time on flaky screed, it sounds like they have over milked or watered it to make it flow better, BIG MISTAKE.

 

[Artisan Ceramic]

Thanks to all for such sound advice. Will update when job is complete.