• Underfloor Heating by uHeat

Water UFH New screed down - trying to figure tiling out approach!

Discuss New screed down - trying to figure tiling out approach! in the Underfloor Heating area at TilersForums.co.uk

GrayD

New to TilersForums.co.uk
Hi all,

I'm new to the forum but have read many posts over the past year as I have created and tiled a wet room and also created and tiled a bathroom in my house that we are renovating. I've also tiled our utility room too. Thanks for all the tips & tricks I learned!

So, I'm ok with tiling walls and simple floors (they get better each time!) but I'm no expert by any stretch. I have all the relevant tools, etc but haven't ever tiled on a new screed floor.

So, here's the background: (bear with me!)

We had a wet UFH system (ProWarm) laid under a 45mm flow screed and the 45m2 floor has been down now since 29th March - nearly 7 weeks. UFH hasn't been turned on. The screed company that laid the floor had to change their material provider last minute because the other one messed up their schedule or something. I'm 90% sure the screed is not anhydrite but I am not 100% sure... There looks like there could be something that looks 'like' calcification on the surface but it's not all over and really only in a few patches here and there. I didn't order anhydrite but I can't be sure what's been laid. Here's the reason why...

The floor company who laid it down created a 4-5mm difference between two areas (thermal break between heated and non-heated floor areas) by not setting it out properly I guess but I only saw this after I trimmed the Celotex thermal break to floor level between the two areas.

They are refusing to deal with the issue so we have fell out now because to me they should sand back the higher area as they knew I was tiling the whole floor across the thermal break. It's only a small area that's too high - 3m2 max so no big deal for them. The upshot is that they aren't coming back to me on whether the floor is or is not anhydrite.

So, I am going to treat it as if it is anhydrite just to be 100% sure we don't get a failure. I'm also going belt & braces on it because I don't want any issues at all.

What I am thinking is as follows, please do tell me if I am wrong, have chosen the wrong product(s) or there's anything I have missed or just not thought about - thanks!

Porcelain tiles on the floor:
1. prep the floor by getting rid of any points, etc and then sweep & hoover it
2. prime the floor a couple of times with Mapei Eco Prim Grip
3. lay down a Durabase CI membrane across the whole area - wall to wall and over thermal break -
4. use Mapei Kerquick adhesive (or better to use Kerakoll Biogel maybe?)
5. use Mapei Ultra Colour Plus grout

Seems so simple when I have written now (!) but I want to be certain I am going about this in the right way.

Thanks in advance for any pointers, appreciated.

Ps. any clues on how to stick down the Durbase would be appreciated too - Kerquick with Latext Plus? Not sure.
 

Localtiler

Trusted Advisor
Professional Tiler
JOTM Winner
First thing, determine if the floor is cement or anhydrite. Post photos and take it from there, no point guessing !
 

hmtiling

Trusted Advisor
Professional Tiler
JOTM Winner
Sand the screed so you can see aggregate. Commission the heating. Test for moisture and make sure it's below 75% relative humidity. Do this with heating off for 48hrs. Barrier prime. You can then fix matting and tiles with most c2's and all s1's. I'd use a rapid C2 suitable for ufh for the membrane then a standard s1 for the tiles. Good luck
 
OP
GrayD

GrayD

New to TilersForums.co.uk
Sand the screed so you can see aggregate. Commission the heating. Test for moisture and make sure it's below 75% relative humidity. Do this with heating off for 48hrs. Barrier prime. You can then fix matting and tiles with most c2's and all s1's. I'd use a rapid C2 suitable for ufh for the membrane then a standard s1 for the tiles. Good luck
Appreciate the advice, thank you.

I'll look up some C2 and some S1 to use.
 

jcrtiling

Trusted Advisor
Professional Tiler
TTA Member
Hi all,

I'm new to the forum but have read many posts over the past year as I have created and tiled a wet room and also created and tiled a bathroom in my house that we are renovating. I've also tiled our utility room too. Thanks for all the tips & tricks I learned!

So, I'm ok with tiling walls and simple floors (they get better each time!) but I'm no expert by any stretch. I have all the relevant tools, etc but haven't ever tiled on a new screed floor.

So, here's the background: (bear with me!)

We had a wet UFH system (ProWarm) laid under a 45mm flow screed and the 45m2 floor has been down now since 29th March - nearly 7 weeks. UFH hasn't been turned on. The screed company that laid the floor had to change their material provider last minute because the other one messed up their schedule or something. I'm 90% sure the screed is not anhydrite but I am not 100% sure... There looks like there could be something that looks 'like' calcification on the surface but it's not all over and really only in a few patches here and there. I didn't order anhydrite but I can't be sure what's been laid. Here's the reason why...

The floor company who laid it down created a 4-5mm difference between two areas (thermal break between heated and non-heated floor areas) by not setting it out properly I guess but I only saw this after I trimmed the Celotex thermal break to floor level between the two areas.

They are refusing to deal with the issue so we have fell out now because to me they should sand back the higher area as they knew I was tiling the whole floor across the thermal break. It's only a small area that's too high - 3m2 max so no big deal for them. The upshot is that they aren't coming back to me on whether the floor is or is not anhydrite.

So, I am going to treat it as if it is anhydrite just to be 100% sure we don't get a failure. I'm also going belt & braces on it because I don't want any issues at all.

What I am thinking is as follows, please do tell me if I am wrong, have chosen the wrong product(s) or there's anything I have missed or just not thought about - thanks!

Porcelain tiles on the floor:
1. prep the floor by getting rid of any points, etc and then sweep & hoover it
2. prime the floor a couple of times with Mapei Eco Prim Grip
3. lay down a Durabase CI membrane across the whole area - wall to wall and over thermal break -
4. use Mapei Kerquick adhesive (or better to use Kerakoll Biogel maybe?)
5. use Mapei Ultra Colour Plus grout

Seems so simple when I have written now (!) but I want to be certain I am going about this in the right way.

Thanks in advance for any pointers, appreciated.

Ps. any clues on how to stick down the Durbase would be appreciated too - Kerquick with Latext Plus? Not sure.
Have you paid them .
 

Glynn

Company Support
I am thinking anhydrite. It just doesn't look the right colour for sand/cement and the surface seems to have a slight sheen. It also seems as flat as a billiard table. You can do a simple test with PH paper that will give an indication of the screed type and it should indicate green or purple but the best way to find out is from the people who supplied it (Humble pie?), and it won't matter which screed it is it can still be tiled but with different prep needed. HMTiling's advice is good.
 
Top
Please enable / Bitte aktiviere JavaScript!
Veuillez activer / Por favor activa el Javascript![ ? ]