Hiya - we're looking at putting down 55sqm of 15-4 engineered wooden floor over concrete. I estimate the concrete varies by 5 to 10mm over the area. First 2 fitters who came said they'd latex to get the surface flat and fit the floor floating. Latest fitter (recommended by the wood supplier) is saying glue it down, and any uneveness would be removed by thicker glue. (4 x 16kg of RawMar mentioned in quote?) Alarm bells are ringing - any advice appreciated Cheers Craig
Did any of them do a Relative Humidity check of the concrete? Has a liquid dpm been mentioned? How are they preparing the concrete? Pictures of the sub-floor would be good..
Same as Wes said really we need a bit more info, although gluing down is the best way to install subfloor will need some attention first
Thanks for the reply. The first fitter who came to look 4 months ago said it still needed to dry and it takes 3 months, so I'm hoping its all properly set now. Second fitter's quote has Polythene DPM 1000 gauge listed. Can't see anything about DPM on current (3rd) fitter's quote, unless that's what Rawmar is? So what sort of prep should I be expecting the fitter to suggest? Couple of pics of the concrete floor (with thin layer of latex over it) attached: Concrete floor poured in 3 pieces with no reinfircing of day joints, by the rougue builder we had in at first - hence scared of jumping with a fitter and want to know they know what they are doing. So cracks have appeared, but seem stable. The concrete has had a very thin layer of latex overit to stop the concrete dust killing our lungs :-/
Really, this is a question of what feel you'd like when the floors finished and what you'd like to spend on the installation. My preference would be a mix of the 2nd fitter (Latex levelling) and 3rd fitter (gluing). Floating an engineered floor will leave you with a louder sounding floor when walked on. Glued down will leave you with a nice solid sound. I'd prefer to level the floor pretty spot on rather than a thicker set of adhesive (10 mm) in places that may lead to slight deflection and possible excessive creaking. However, I've not used Rewmar (If that's also the adhesive that's being used as well as the dpm). The fitter may be comfortable due to experience with that product. Hang on for other input from the lads here.. The Rewmar MB can be installed up to a relative surface humidity of 98%, so you'd be pretty safe there.
Do you know what that latex is? You can't use a Dpm over some latexes. I wouldn't be happy bonding to that subfloor. Your best off getting the floor levelled and floating the wood on a decent underlay once the screed is dry.
concur fully with Merit & Brench... get the subfloor nicely prep'd & float on a decent quality underlay... Happy days
Hi, In my opinion you would be best to get the sub floor leveled prior to installing your floor. It is true that you can get over some uneven patches in a sub floor by using extra adhesive, and many people do this, but going by your description of the sub floor levels I would expect that it would be cheaper and more sensible to level the floor then glue down the wood rather than use excessive adhesive to pad it out. Rewmar MS Polymer will work with all levelling compounds. If you want to discuss this you can contact Rewmar technical support on 0870 609 1548 I hope this helps.
Hi I may have come in a bit late here but from what I've read I definitely wouldn't go down the sticking route. If you had a "rogue builder" you can bet your life that the skim of latex has no primer underneath let alone a dpm in the concrete, so if you stick to that then ANY movement in the wood will rip it off the dusty concrete underneath. Other than chipping the latex up and starting from scratch, you could latex over the top with arditex NA then use a sheet DPM, then float the wood on an underlay like timbermate excel, and just hope that the work your "builder" has done doesn't fail!. If I were doing the work for you I couldn't guarantee it though, unless we chipped up the existing latex and started from scratch!
