Damp Proofing Question

Laying engineered wood in basement flat

I have commissioned a flooring company to lay engineered wood flooring in an old basement flat.
The previous solid wood flooring buckled (however there was a burst pipe to the rear of the property which has now been fixed).

As the floor was old, damp and uneven the flooring company have
1) Used a PVA and then a self levelling compound (Universal Setcrete )
Their next steps are to
2) Lay a liquid DPM wait for this to dry
3) Lay a plastic sheet, then put a fibreboard underlay
4) Lay the new engineered wood flooring

However, I was concerned as 36 hours later the self levelling compound is not fully dry. It was supposed to take 3-24 hours. As such I had a look at Universal setcrete website and it states a DPM should have been laid beneath the self levelling compound.

My question is - who is right? Should the DPM be laid before or after the Self levelling compound?
Should I ask the flooring company to take up the self levelling compound and start again by installing the DPM? Should the DPM be liquid or physical? My surveyor had suggested Oldroyd xs rather than a liquid one to prevent human error causing cracking.

3 Answers

Best Answer

Please see Stages 1 - 5 below

1 / DPM Sheet 1200g
2 / Level Compound
3 / Oldroyd Xs DPM
4 / Underlay
5 / Wood Flooring

What they are doing is
1 / Applying PVA to the base
2 / Laying level compound straight on to an unknown damaged floor base
3 / Adding a liquid DPM
4 / DPM sheet under the underlay
5 / Underlay
6 / Wood Flooring

Besides your surveyor had suggested the use of Oldroyd xs rather than a liquid one to prevent human error causing cracking.

Hope this helps.
George Kalavashoti
Blank Canvas Constructions

Answered 4th Apr 2015

Blank Canvas Constructions Ltd

Member since 21 Jan 2015

I'm not a builder, but have laid plenty of floors in old vicorian properties, usually with underfloor heating, some wet, some electic.

For me, I have used liquid Dpm a lot, and have always put it directly over the concrete sub floor. ( taken it up the walls where necessary ).

Whenever I have used the modern self-levelling compounds, I have mixed them with water, then poured !
So to me, it would suggest that they are not waterproof, and would be hydroscopic, thus drawing up the moisture.
Hence, should be poured above the Dpc !
I would have used, liquid Dpc, cement board, (say Baker board ), which both helps to level the floor and provide some insulation.
Then the heat mat, ( if required), set in self levelling compound.
Then tiles / wooden floor / vynal over !
Southsea plumbing

Answered 5th Apr 2015

Southsea Plumbing, Heating, Electrical & Gas Services

Member since 8 Nov 2010

totally agree with blank canvas, not many of us about

Answered 23rd Apr 2015

Signature Design, Build and Restoration Ltd

Member since 9 Apr 2015

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