Help - floor screed issues

[Satsunday]

I'm not sure if there is a problem but our screed floor went down end of October and there is still over 30% moisture in it. Why on earth could that be the case? We were told it would dry at a rate of around 1mm per day.

Also I've been googling and the thickness of our floor is 51mm. I've read that over underfloor heating it should be more than this?

Just don't know who to ask other than people on here as our builder just says everything is fine.

Has it got a damp proof course?

I think so - is that the membrane underneath it? If so I remember that going down on top of some insulation (on top of concrete I think). Then the underfloor pipes were laid on the membrane. Then screed poured in.

Just moved a plastic bag and this is how damp it is underneath. Underfloor heating has been in low for weeks. Maybe it's normal but doesn't seem right to me...

We had a problem with this in the kitchen so in the basement I drove the builders nuts refusing to let them lay the floor until it had reached the appropriate humidity levels.
It's not easy at this time of year.
Have you got enough ventilation? Windows open when heating is on?

Thanks for your reply. We've got dehumidifiers now but had nothing for the first 2 months and didn't think to open windows, bit daft really in hindsight as it was like a greenhouse in there. So I can imagine it hardly dried at all for the first few weeks. I guess I'm just expecting it to dry quicker ever since we got the dehumidifiers but in 4 weeks I haven't seen a change.

Following this with interest as our screed has just gone down and out builder reckons he can lay the floor in 2 weeks!

You can get more expensive very quick drying screed so worth finding out which type yours is. If it's the same as ours then more like 2 years at this bloody rate!! Apparently if tiles go on before its dry, bubbles can form and tiles can lift up.

Our builder thought days! They just wanted the job done!
It was several weeks and then more.
I had a temp and humidity meter in the room and also a prob that checked the concrete.
Winter didn't help.
We had wood laid so i got the max level required from the supplier - any higher and there was no guarantee - and we waited until at that level for 48 hours before it was laid.
Dehumidifier over night alternated with open windows during the day.
Progress was slow and took time to kick off and ages to get even levels.
Is there any change of a leak?

Thanks, we've just switched them off in the day fearing a massive electricity bill. Will also just run them overnight from now on, especially as they're collecting loads of water but making little difference to the water readings taken from the floor.

I've asked our builder about the possibility of a leak but of course that's instantly dismissed as ridiculous! We are wondering whether to just move our furniture in and pretend we have a finished floor. The alternative is to keep living in a tip for however many more months it will take to dry. Argh!

Had no idea at all it would be like this, not sure having underfloor heating is worth it really.

Our floors went in mid Dec & u/f heat has been on 2 weeks now (low).

I was told 6-8 weeks drying then low height until moisture levels correct then heat off for a week b4 lying tiles.

Hoping to start lying tiles in 2 weeks but no point rushing these things either!

grey have you been told what moisture reading % is ok for tiling? We are getting different answers from our builder and tiler.

Weirdly it is freezing outside here today so the underfloor heating would have been on low all night, but the dehumidifiers have hardly got any water in them. I assumed the heat would make the water rise to the top so more water would be in dehumidifiers.

Apologies for height instead of heat!

I don't know the % but I will find out & come back to you.

Thanks. We're in week 14 now and hardly any change in % each week but builder says when it gets to 20% thats ok for tiling. I think that's probably not true.