In a spot of bother... Anhydrite screed!

[High Peak Tiling]

Hi guys, I have a site meeting tomorrow with the customer and father inlaw (architect) so I bringing my dilemma to you guys.

A quick run down on the problem and why..
I priced a job up a while ago which entailed hallway and kitchen tiled in black Riven Slate onto concrete screed. being a brand new floor and dusty. I had a look and queried a if it was anhydrite, customer not aware said they would be in touch. (some lafarge etc special screeds look as white/light and smooth as anhydrite these days!)

Once concrete screed was confirmed I priced for normal cementitious adhesive.
on several occasions I asked for customer to check out the invoice from floor layers and also with architect.

Arrived onsite today fitted Dura matt with Weber SPF, 3pm builder turned up and dropped into conversation the words anhydrite screed... I coughed and spluttered and got straight onto the customer who was very apologetic and non the wiser with the difference between cement and calcium sulphate... After a quick lesson in why not to mix them, I had to get off home to ponder the options..
I gave the floor a good 1:3 coat of primer and it took a good while to soak in and dry...
so the chances of it being ok...?

I would normally prime twice to make sure the floor can't absorb any more and then be ready, working on the pretence of it being cement I gave a normal coating.

Ok, so my question, do I do the following option:
1, sign a disclaimer removing myself and all company comeback if and when the matting de-laminates off the entrigite (customers idea)
2, (my idea) rip up all matting (30m2) scrape whole floor, sand thoroughly then prime accordingly.

Cheers guys.

 

[cam_low]

For the sake of a couple days labour and the matting price I would be going down the route of number two. It would play on my mind too much and give me a headache until it finally fails then no doubt you will get dragged back into it !

 

[High Peak Tiling]

For the sake of a couple days labour and the matting price I would be going down the route of number two. It would play on my mind too much and give me a headache until it finally fails then no doubt you will get dragged back into it !

Thanks Cam, the only downside is all the work today and the bugger it will be to get it up!

 

[Ajax123]

Ok. I have some questions for you first.

1. Has it got UFH and has this been comissioned and run
2. How deep is the screed and how long has it been down
3. Did you moisture test
4. Do you know who actually supplied the screed e.g. Bardon, lafarge, Tarmac etc
5. Which primer did you use

 

[High Peak Tiling]

Ok. I have some questions for you first.

1. Has it got UFH and has this been comissioned and run
2. How deep is the screed and how long has it been down
3. Did you moisture test
4. Do you know who actually supplied the screed e.g. Bardon, lafarge, Tarmac etc
5. Which primer did you use

Yes ufh
It has been on and tested by floor layers. Screed is 50mm thick

Has been moisture checked by floor layer only due to customer misplacing my sealing tape!

Has been down 2 months and has been on to speed up drying!!! (Floor layers advice )

Screed type: not a clue.. Only just found out it is anhydrite.

I used Weber PR360 at 1:3

 

[High Peak Tiling]

 

[Ajax123]

Looking at the pics it looks pretty wet still. Two months is only just long enough in natural drying conditions. If the heating has been on at high temperature (flow temp of 45to 55degrees ) then you stand a chance. I think though it is likely to put you at risk to continue tiling. My advice therefore would have to be undo what you have done and prep the screed properly once it has been confirmed dry.

 

[Diamond Pool Finishers]

Also a disclaimer is not worth the paper it is written -on, as we all have a duty of care under english civil Law, if you know there is a problem then in law you must not go over it..........

 

[High Peak Tiling]

Job update.
Had the site meeting.
Architect as many I have met are full of themselves and are always right!!

I gave two options:
1, pay for what I have done and leave the job.
2 get full confirmation from screed company with all checks of screed and my prep to be satisfactory for tiling to commences.

We shall see what the company comes out with

 

[Spud]

edited

 

[Spud]

i would rip up the matting , sand the floor and completely hoover it up moisture test it then fix the tiles with anhyfix I would also prime the subfloor before tiling

 

[pete f]

why anhydrite screed if its being tiled it just doesn't make any sense

 

[Ajax123]

why anhydrite screed if its being tiled it just doesn't make any sense

Not sure what you mean??

 

[jonnyc]

i would suggest same as alan and gary.
what puzzles me is that you did not recognise that this screed was different than sand/cement/
i am assuming that you have never laid on to anhydrite before and therefore did not recognise that this screed could not be sand cement

 

[Spud]

why anhydrite screed if its being tiled it just doesn't make any sense

there are pro and cons with anhydrite but one of the big benefits is its self compacting and is a better conductor of heat than sand and cement screed so its why it is often specified over hydronic heating systems

 

[High Peak Tiling]

i would suggest same as alan and gary.
what puzzles me is that you did not recognise that this screed was different than sand/cement/
i am assuming that you have never laid on to anhydrite before and therefore did not recognise that this screed could not be sand cement

hi Jonny, I wasn't sure but did quiz the customers and architect on my thoughts of it being a Anhydrite on pricing the job.
I was unsure because you find a lot of freshly laid anhydrite screeds look very similar to some special lafarge, cemex, tellings screeds these days.
bearing this in mind, The architect was telling me it was concrete (definition: rough building material made from a mixture of broken stone or gravel, sand, cement, and water)

on this information I proceeded.

 

[AliGage]

bearing this in mind, The architect was telling me it was concrete (definition: rough building material made from a mixture of broken stone or gravel, sand, cement, and water)

on this information I proceeded.

I think this is the point JC is making. It wouldnt of looked like described above.