Anhydrite screed high moisture contents

[RobertaG]

Hello everyone, I hope someone can have an idea of what it is going on.

We have an anhydrite screed poured on the 25Th of January  on top of underfloor heating and vapor proof membrane.

 

 

 2cm in the old house and 5cm in the new extension of the house.

 

We have tested it multiple times( with hygrometer) lowest reading have been 78 end of May.

After 4 weeks we tested another point partially under the kitchen and it was 88.

 

We had underflooring heating off for 4 days before any reading, 

3 dehumidifiers constantly on night and day .

 

We got in touch with the manufacturer  SLS liquid screed https://www.southernliquidscreed.com/

And we know that laitance removal have never been done.

You can imagine how hard it is to remove laitance now not only because the layer gets harder and harder  but also because the kitchen have already been installed .

 

Anyway free of charge Monday have been done. I have attached photos , it looks like in some areas there are pocket of air.

 

I brought and Fball hygrometer and I am running another test. Looking at 87 rh at 22 degrees . Very high humidity today 70% in the house.

 

I have read everything I can possible can , we are arrived to a point where the builder doesn't care and the building inspector is asking for a moisture test calcium carbide test ( which as far as We understand is more reliable than hygrometer).

Probably is best to remove the kitchen and go  again  with another screed.

 

We have started to think all sort of scenario , from the slab probably still being wet and influencing the moisture result  to the screed that wasn't able to breath for 8 months because of laitance . 

If anyone have any idea about what it is going on let me know.

 

Thank you 

Roberta

 

 

[tonyshouse]

Here is an offer you can’t refuse. Drill a hole in each bit either 20 or 40mm deep, collect the dust, seal it in a plastic bag, label each one seal them again in another bag. Send in the post or deliver to me. I will weigh the sample, dry it in my oven, re-weigh it and calculate the moisture content.

 

what are you measuring with? 

[markc]

Unless your house has been under water since it was poured I can’t see these reading being anywhere near correct.