Laying laminate on concrete floor without DPM ?

[ivixor]

Hi,

In removing old flooring, the brown bituminous 20mm thick layer in the hallway of my ex council house broke up and had to be thrown out.

I understand that this served as the DPC, which makes sense, as underneath this layer the concrete felt and smelled damp.

I've just added about 10-15mm of self levelling compound, but now need to reinstate some kind of DPM. I have bought a large sheet of the thick damp proof membrane designed to go under laminate.

I planned to lay this on the levelled base, tape all joins, lap up walls best I can, then put underlay on top of that and then laminate.

Will that do? Or will I get a damp disaster?



Cheers!

 

[crazydaze]

You need a product that will either seal the floor - liquid dpm, whichshould be vailable from the same supplier or manufacturer of the screed that you used, or you need something that will allow the floor to breath beneath the laminate similar to Pergo Moisture Bloc Xtreme http://www.pergo.com/en-gb/Consumer/Products/Accessories/Comfort/Moisture-protection/

or F-Ball Isolator http://www.f-ball.co.uk/product_detail.asp?catID=damp&product=Isolator or similar.

This will allow the floor to breath and sealed correctly will not allow damp penetration.

 

[ivixor]

Thanks,

Is there any reason as to why a liquid DPM is ok but a polythene sheet DPM isn't? I ask as I already have the sheet...

Cheers

 

[crazydaze]

Thanks,

Is there any reason as to why a liquid DPM is ok but a polythene sheet DPM isn't? I ask as I already have the sheet...

Cheers

The sheet will encourage the floor to sweat, you need to seal the floor if you go down that route, but you can only use a liquid dpm that is suitable for use with the product that you screeded the floor with, so ask the manufacturers recommendations

 

[dbinit]

There is heavy duty flooring polythene out there that has tiny holes that let the floor breathe. The specifications you are looking for are 1000mg weight and a permiable rating of 1 . We do normally stock it at www.woodenfloorshop.co.uk but are sold out right now. Hopefully your current DPM is of the same or equivalent spec and it will be fine. Otherwise a liquid dpm as advised is advisable.

 

[mikeey84]

I had a similar issue and used a tanking slurry (KA tanking slurry) which cost about £50 for enough to treat 7sqm. Make it up and brush it over, let it dry, and then a 2nd coat. Very easy to use, similar to a SLC, except it doesnt Self level, and a lot cheaper than epoxy or similar solutions