How long for concrete floor to be safe to put laminate down?


Had a conservatory built.
Concrete floor is about 5" thick and was poured on May 1st ready mixed (5 weeks ago). It was ok to walk on the next day. It also has a DPM under it. Not knowing anything about the concrete, it's whatever standard stuff that might be delivered by a contract concrete supplier.
The question I have (and I have researched on google as well but would like further opinions), is how long after the floor has been poured is it safe to lay laminate flooring down?
I have a DPM ready to go on top of it and fibre board to go under the laminate.
The laminate packs say 1 week per cm which would mean, based on that advice - 12.5 weeks before we could put the flooring down. Advice across various google results suggests 6 weeks. Would we really have to wait another 7 weeks before putting the flooring down or should we be safe to go next week or even today?
It has been rather warm over the last couple of weeks and the room has been vented almost every day.
Thanks in advance for any advice.
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Paul* wrote:

Standard practice is to tape a small sheet of clear plastic to the floor & leave 24 hrs. Any condensation on the plastic indicates that its not dry.
If the base has a DPM under it & you put a DPM over it, where will any moisture remaining go?
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Dave - The Medway Handyman
www.medwayhandyman.co.uk
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Hi Dave,
Thanks for the reply. I'll try the plastic tip.
With regards to the DPM, I can happily ignore the advice on the packs and take the DPM bac? Must admit, it makes sense that trapping the moisture in isnt wise. I suppose at least without the DPM, there is scope for it to continue evaporating.
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Paul* wrote:

kind of material that swells when it gets wet? And would laminate flooring allow moisture to get out? I'd be VERY careful to make sure the concrete is dry enough because if you mess up now it will be expensive and a real bother to put things right. It's only a few weeks :-)
A L P
A L P
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Paul* wrote:

I didn't mean don't use it, I meant make sure the floor is dry before you use it. Sorry if that wasn't clear.
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Dave - The Medway Handyman
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I have an old house and its scullery has a floor which is slightly below ground level. It's also an unattractive plain cement floor. So I decided one day to put down some vinyl to brighten it up. A week later I found that I was treading on puddles under the vinyl. What had happened was that the evaporation of moisture had been stopped and the water had just built up. I tool the vinyl off and everything was restored.
Moral - don't trap the evaporation.
Rob Graham
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Thanks again for all the responses. We're going to leave it for a good 8 weeks now. Makes sense.
I will ask, we did actually take the DPM back. Is it really really necessary if there's a DPM underneath the concrete? Is it essential that we put the DPM on top of the concrete underneath the fibre board?
I can always go and buy it again if I need it.
Thanks again
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As I inferred in my last post, I think that not only do you not need the DPC above the concrete but that it would be a retrograde step to put it there, in other words positively negative!
Rob
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Cool. Thanks for the absolute confirmation Rob. Much appreciated.
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