Is this a damp problem?

FTB2020LDN

Hi there, 
I am having new flooring fitted this week. The concrete that was down was a bit wonky, so needed screeding. This was done yesterday morning and the fitter was back today to fit the floor, but said they couldn't as black spots had appeared everywhere on the floor (pictures below). They have told us we 100% have a damp problem... but the concrete underneath was not damp, the carpet and underlay they took up was in perfect condition, we have no damp smell at all in the house etc.
To me it just looks like it needs longer to dry? But of course, I have no idea!! We didn't stay there last night so heating hadn't been on for a couple of days and windows were closed, we have now left the heating on and windows open to allow for heat / air flow.
Any advice welcome - thanks in advance!!

FreeBear

How long has the self leveling compound or screed been down ?

It does look like uneven drying. Dependent on temperature and thickness, it may only take a day or so to dry out, or it could take a week. A dehumidifier plus heating will speed things up a bit.

FTB2020LDN

FreeBear said:

How long has the self leveling compound or screed been down ?

It does look like uneven drying. Dependent on temperature and thickness, it may only take a day or so to dry out, or it could take a week. A dehumidifier plus heating will speed things up a bit.

Thanks! It was laid yesterday, so it's been down approx. 24 hours or less (not sure what time the guy finished yesterday as I wasn't there, but he said he'd be done by lunch time yesterday. These pictures were from 8:30am this morning.

FreeBear

FTB2020LDN said:  It was laid yesterday, so it's been down approx. 24 hours or less

Ideally, you don't want to be walking on it for at least 24 hours, preferably 72. If you rebook your fitter for next week, the floor will have cured fully and dried out. A simple case of trying to rush things methinks.