Engineered wood floor prep advice

[gregmcateer]

Hi folks,

I am approaching (HOPEFULLY :roll: ) the end of our extension build and need to seal the concrete screeded floor before laying engineered oak floor, (SWMBO insisted on UFH and wooden floor - gulp!).

Advice please - To seal the floor - DO I need something such as SIKABOND DPM, or is there a cheaper, (though effective), alternative?

Many thanks in advance

Greg

 

[Modernist]

What are you sealing against? Presumably the floor has a separate damp course. I would just lay it on as is. Heat rises through whatever you put on top of UFH unless it is a specific insulator. Mine works in the bathroom through 60mm screed, 25mm ply, 15mm limestone tiles and is fine. In living areas I have cement soffit board over 50mm Poly insulation slabs containing the pipes with ally spreader plates and then engineered floor above with no problems.

My only problem was putting pipes along the sides of joists with chipboard flooring then engineered which is slow to heat as there is no direct contact with the heating pipes. If they are in screed you will be fine.

 

[gregmcateer]

Hi Modernist,

Thanks for your reply.

Yes, the likely floorboard supplier says there should be a DPM belween the screed and the finished floor. There is a DPM (blue poly sheet) on the Xtratherm insulation, onto which the pipes are laid, then 75mm screed.

From what you are saying, you don't feel there is any need to stop any moisture, (I have let the screed dry for 2 months), which may still be in the screed.

Greg

PS Where did you get your flooring?

 

[RogerM]

I think I'd run the UFH for a few weeks before laying the oak floor. We first used our UFH about 6 weeks after the screed was laid and for the first couple of weeks using the UFH the condensation was horrendous as the warm slab shed the water (and that was over a relatively dry mix) . I would suggest not waiting until the weather gets really cold because the chances are that you'll want the windows open to clear the condensation for the first few days at least. A layer of the thinnest, cheapest hardboard laid on the floor would be sufficiently porous to allow water to escape whilst providing a surface that is easy to keep clean. I would only lay the oak floor after the condensation levels have fallen to normal levels - probably after 2 - 3 weeks - but if you can wait longer, so much the better. After that I would be surprised if a membrane was necessary, and in fact I would be tempted to let the floor continue to breathe under the wood.

 

[Modernist]

Just to be clear the point above is very valid. It is essential that the screed is allowed to dry out thoroughly. It is best to run the UFH at a very low level for up to 3 months to achieve this. Thereafter I also think any additional DPC is superflouous.

 

[gregmcateer]

Thanks for the advice,
Greg