anhydrite floor screed

[barno101]

We are our wits end ,,
We had an Anhydrate Floor screed laid at 40 mm and was left for 6 weeks to dry ,, the problem we got is the tiler laid the porcelain tiles on the floor he primed it ,and use rapid set flexi adhesive, followed all the correct procedures .
The plumber ,then turned on the underfloor heating and left it on full blast and was on for a long time , he never raised it slowly like he should have day by day . now the tiles have lifted .
The plumbers says the floor wasn't dry enough and thats what caused them to lift .
but we are saying he should have turned it up slowly ..

Any advise please

Cheers

 

[Ian]

Could you give us a bit more information if possible please. Was the heating commissioned (turned on and run up/down) prior to tiling? Was the floor sanded to remove any laitence prior to tiling? What adhesive was used? How long after the tiling was completed was the heating turned on?

 

[Time's Ran Out]

It's always the plumbers fault! :smilewinkgrin:
Did you know all this information at the time and just let the professional handle it or is this information gleaned from forums such as this?

 

[Turkish tiler]

What adhesive did he use & how did he prep floor before he lay tiles ?

 

[Stef]

Could you give us a bit more information if possible please. Was the heating commissioned (turned on and run up/down) prior to tiling? Was the floor sanded to remove any laitence prior to tiling? What adhesive was used? How long after the tiling was completed was the heating turned on?

As said here a bit more info would help.
It doesn't sound great to be honest!!

 

[barno101]

All the latency was taken off ,,the tile adhesive was the one recommended by for these floors, BAL rapid set flexi as far as i know . the heating was turn on a bout 2 after tiling and it was put on full blast

 

[Just Rizzle]

I think there both to blame I never use cement based adhesives on anhidrite floor as there is always going to be a reaction. anofix by tilemaster my preferred choice ,I also never tile a floor befor its commissioned. why didn't your tiler recommend a decoupling mat. also your plumber should of known to slowly raise the floors temp.how big an area was it?

 

[barno101]

the area was 144m2,it was a new build house, there is a an ongoing argument that the plumber is saying the floor was not dry enough ,, but we are saying if the heating was raised gradually as it is supposed to ,then the tile may have not come up ,, but if the floor was still damp the plumber is saying that ,that is the problem ...
there is only about 60% of the tiles that have com loose ,, and the grout has cracked where there is a congregation of pipes on the underfloor heating as it goes into the manifold s
There are three manifolds in the house

 

[barno101]

he prepped the floor properly i.e. two coats of primer after cleaning the floor area of any residue ,,the tiler has done everything right .. the plumber is saying that the floor area was still damp ...

 

[Ajax123]

so many errors in one small floor... Where to begin.

 

[Chalker]

The biggest mistake here was NOT, heating the floor BEFORE tiling.
even with 6 weeks drying time, his time of year it would not have been dry.

was the screed tested for moisture??

i have made this now to dry our screeds if the boiler can't be commissioned in time for tiling. Can be connected to manifold.

 

[Sean SML Tiling]

That's a great bit of kit there.

 

[Chalker]

That's a great bit of kit there.

Total cost about £700!!
got £250 back in the first job off the builder for hire, as the gas was not going to be connected until a week before customer moved in.

 

[Sean SML Tiling]

Was gonna say I bet it will pay for itself in no time.

 

[Dave]

Just to add to the comments already posted , cement based adhesive is fine on these screeds if the screed is dried and primed correctly , so NO ! You will not always get a reaction with cement adhesive to calcium sulphate screeds .. You get a reaction if there's still moisture or it's not prepped properly ..

As as for your situation , then the screed should have been commissioned before tiling commenced and your tiler should have known this.

But and this is a problem also caused by the plumber just whacking on the heating , that is ludicrous ... If he had turned it on very low and increased it in small amounts , then as long as the floor was dry to start with , I think your tiles would have stayed down... Anhydrite screeds are stronger than a cement based screed and not prone to cracking like a cement screed does when first heating them , hence why a heated floor should be commissioned first as all heated screeds should be really but you might have been fine heating slowly as I said , the argument is , was the screed dry and was the plumber notified that the heating should be increased slowly ?...

not it a good situation to be in but it does seem the fault could lay with both the tiler and the plumber.

 

[Just Rizzle]

I disagree with dave no one these days should be mixing. theres plenty of products out there there that are compatable with the appropriate substrates. you wouldn't mix crossply tires with radials on your car, so why use cement based adhesives on anhydrite its a no brainer . like for like every time

 

[barno101]

Cheers for the info Dave ,, Ive got a meeting in the morning with both the plumber and tiler to get to the bottom of this ,,and I don't want to pass blame on any one of them ,but I need to get to a decision as to whether it is the floor being damp ,,or the heating being put on too quick too high temperature ,, at the end of the day the tiles have to be replaced and somebody has to pay for this ,,, if it was a small area say 20 to 30 m2 I would pay myself but this is a big area
Cheers

 

[Dave]

I disagree with dave no one these days should be mixing. theres plenty of products out there there that are compatable with the appropriate substrates. you wouldn't mix crossply tires with radials on your car, so why use cement based adhesives on anhydrite its a no brainer . like for like every time

Can I ask what you used before gypsum adhesives ray ?


yes I agree with gypsum to gypsum now we have the choice , just your statement on cement based adhesives was incorrect. Imo ..

 

[barno101]

Just an update ,,
Had a meeting with Tiler and Plumber ,and after a few strong words from all parties involved ,,we came to a decision, that they were both at fault and we have decided to ,,all of us put it right and retile the area ...
Tiler for not checking dampness ,, plumber for whacking the heating on to high ( and leaving it on for 5 days )..
Thanks again for all your comments

 

[Stef]

Glad you got a satisfactory outcome & the plumber & tiler have learned something new..

 

[Time's Ran Out]

Now I've read through this thread I cannot for the life of me see how the tiler was to blame at all!
If the floor wasn't commissioned by the plumber before tiling and he 'whacked' it on for 5 days the plumber is at fault.
These jobs should all be signed off at all stages and not just the cursory - yes it's been switched on/ off that have no records to pass to the next trade.
When the floor has been handed to the tiler it should have a full history ! How many times do we turn up and get told ' oh it's been down months'.
Had a floor a couple of years ago that was reading 32degrees in the middle and 12 degrees at the walls - what does that say about the zonal layout of his pipe work and how are we to tell under 80mm of screed!
I make it a point in my invoice now to tell the end user that the floor must be turned up slowly - but what guarantees do we have that it's followed.

 

[Just Rizzle]

the tilers fault is
a) he didn't take a moisture reading from the floor to ensure it was safe to tile and
b) tiling the floor befor the heating system was commissioned.

the best peace of kit I have is a moisture reader. cost over £300 about 12 years ago its made by sovereign it gives me peace of mind as well as my clients knowing in tiling a substrate its dry and safe to do so.

good luck barno101
hope all goes well this time but one thing what addy will your tiler be using this time round?

 

[widler]

I bet plumber said it didn't need turning on, most the time they have to go out of there way to connect it up.
Plumber on my job at mo said "why, it will only move again when we turn it on again when it's tiled, complete waste of time, I've never heard owt as daft in my life"
I still made him turn iton though [emoji41]

 

[Dave]

Common practise when testing an anhydrite screed for RH% is a Hair-hygrometer (original) or (digital) or the carbide bomb test.

how many of you guys have a hair-hygrometer ?

 

[Ian]

I've got 2 digital ones, set into foam blocks.

 

[peteablard]

Digital for me too, it's a F Ball one think it was about £100

 

[Stef]

Digital for me too.
Could do with another one..

 

[Sean SML Tiling]

I got the digital f ball and small digital tester which is not quit as good. Had to buy 1 for my anhydrite floor. Best 100 I spent

 

[White Room]

I've never seen one of these screeds let alone tiled one....

 

[Ian]

Everywhere round here Mark, went to see another failed one today, in an ex show home for a very well known national builder.

 

[White Room]

If I mention the screed no one seems to have a clue what I'm on about...