Recommendation needed for DPM under engineered wood

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Am wanting to get engineered wood installed in the ground floor rooms but the flooring company have said that around half of the floor area (different material than rest of house as was added as front extension) has a moisture content that is a bit too high for them to fit.
The measurement is 4.3 to 4.5 and they have said it should be around 3.5 (im not sure what this is measured as I've only seen percentages for moisture content of floor before)

Anyway, i can't afford the time to wait months for it dry (if it ever would) and want to get the engineered wood installed asap.

Can i paint the screed area with something or lay a DPM sheet down and last the wood in top. I guess the wood can't get glued down.

Any recommendations?? And any brands/materials recommended
Many thanks
 
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As always pics would help, plus more info?

What kind of floors are the floors in question?

When was the extension built?
 
The floor is screed ( I believe it is 65mm thick) and was laid during the last week of June. We were told by our builder that our flooring could be installed after a 2 weeks which we questioned etc. Hes now left and not being helpful at all.
From searching online weve seen allow 1mm per day (65 days) and yet now 100 days later we are still not moisture free.

I feel stuck as the builder won't answer questions. I know there was a damp proof membrane installed with insulation underneath the initisl concrete slab but do not know what went on top of concrete and below the screed.

I'm desperate to get our living space back to a useble state. As this extension was supposed to be a 10 week build starting at start of april.. and we've were messed around by the builders for way too long.
I really need to get the living room useable for my family and am hoping that a dpm under the engineered wood is possible
 
So you have a concrete slab laid on a DPM, and later a 65mm sand & cement screed laid on the Extn. concrete slab.

The DPM should come up in an upstand and tie into the DPC on the inner brick skin or blockwork.

Are the screed and the inner floor at the same level?

How has the join between the screed and the inner floor been made?

The other half of the proposed new engineered floor area is presumably in the main house? Is this half a suspended or a solid floor?
 
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If your floating the wood
I put down a moisture suppressant on new concrete.
The main one I use is F.ball stopgap F78.
2 coats of that can go onto new screeds after 28 days
Then use a underlay like timbermate S3
 
i was also expecting the damp proof membrane to come up to the damp proof course but never saw that and there is definitely nothing sticking up at the sides of the new screed.
is this a problem?

The Old floor is solid and has a deep black bitumen type layer on it. the screed has been levelled to butt up to it, which goes above where the old external wall / window opening was.
 
Reading up on stopgap looks like it could be what I need. .. Any difference between stopgap 77 and 78 ??

and the wood floor company were wanting to glue the floor direct onto the solid floor?

Could they do this directly onto the stopgap covered screed or is further moisture barrier underlay required?
 
The wood company don't know what they are doing if they aren't taking moisture tests.
F78 is for new concrete only.

On old subfloors I usually remove the old adhesive then if rough

Ardex NA
DPM 1c
Ardex NA

Or Fball 1200 pro , then F77 , 1200 pro again.

You can't glue wood onto this system though.

How old is the solid subfloor?
 
The old floor is fine. It's just the new floor that is showing the higher moisture level
 
With you saying it has bitumin on the subfloor that tells me that it could be a pre 1970 subfloor which might not have a damp prof membrane under it.
Make sure you all 100% sure it has one or if wood is glued down you will have massive problems.
On the new concrete F78 is good if floating the floor and go F77 if gluing down.
 
thank you. I'll make sure they check the bitumen floor too. house is 1965 build so you could be right. The flooring company havent raised it as an issue though.
or could we use F77 on the bitumen floor too to save any problems?
 

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