The subfloor in my house is a concrete slab with no DPM. It originally had Marley tiles stuck down with bitumen 'glue', but many of them are missing and I will remove the rest. The floor originally had a carpet laid on top of the tiles, when I lifted it nothing felt, looked or smelled damp. So the floor has been there for 70 odd years, apparently with no damp problems. I don't think the tiles were acting as an effective DPM because their coverage wasn't 100%. Should I still lay down a new DPM or will I be OK without one? I want to put down laminate flooring on top of the concrete, once all the tiles are removed. Are there any reasons the laminate might be more vulnerable to the lack of DPM than the original carpet was?
The damp would effect any water based levelling compound or adhesive..... if laying laminate then a good quality underlay that acts as a dpm should get you by. If you wish to go belt and braces test the moisture level and use a sandwich dpm, i would use Ardex Na after removing any loose residue and ardex dpm1c then top with ardex Na
I'll probably go with the underlay then. If there are damp problems later on, lifting up the laminate and installing a proper DPM/screed sandwich before re-laying shouldn't be too difficult? The concrete subfloor still has a thin layer of bitumen on it which may contain traces of asbestos. Can anyone advise something (cheap and easy) to paint on and seal in any dust? Should be non water soluble just in case. I was thinking dilute SBR, any recommendations?
Get in asbestos aware to test the adhesive residues, then have it mechanically removed, for sweet baby Jesus sake don’t try cut any corners here it could be devastating to your health and I disagree with what the others said, a vapour barrier will do next to nothing it really needs a rh% test then a screed dpm “sandwich” or digging up and replacing depending on the reading otherwise it’s a failure waiting to happen. Sent from my iPhone using Tapatalk
There are always outliers, over the years many people have gotten sick from one event personally I won’t take the risk no matter how small it is. Sent from my iPhone using Tapatalk
God, when I think back to how many 1000`s M ive taken up with an extension scraper. You could run at them and watch them pop like dominos
To be honest we’ve all been idiots about it in the past, but having a friend work in the mortuary puts it into perspective. Sent from my iPhone using Tapatalk
The amount of asbestos in vinyl tiles and bitumen adhesive is laughable. I wouldn’t grind the bitumen if it does have asbestos as that’s the one way your gonna release it into the air Sent from my iPhone using Tapatalk
They say it takes a lifetime for the disease to show up, and I'm old enough that breathing in 1 or 2 fibers probably won't make much difference. So this is mainly for the benefit of the next poor bugger who lifts up the floor, one day after I'm gone. If I paint a coat of SBR on to the concrete, will this cause problems later on if I find that I need to put screed (first layer of the sandwich) on top?
You don’t need a primer, just seal it with the Ardex NA. Your only floating underlay and laminate over it. Primer will break down if the subfloors damp Sent from my iPhone using Tapatalk
Ardex NA is pricey though, if all I'm using it for is to seal in some dust. Can you recommend something cheaper that will achieve the same objective, but would be ok to put the Ardex NA on top of later (only if became necessary)?
If all you are doing is sealing in dust, and I mean if ALL you are doing is sealing in some dust, then don't bother with anything. Just sweep it clean and use an underlay with an integral DPM. and lay your laminate. With regards to would it be "ok to put the Ardex NA on top of later (only if became necessary)" I would suggest that if it gets to that stage you are starting again as the materials will be ruined. Bear in mind that this advice is given without seeing your floor. Alternatively get in a professional who will evaluate the environment, do the correct prep work based on what he has seen, install the floor and give you a guarantee. Your call.
Ardex n/a may seem pricy but is cheaper than hiring grinding and extraction equipment to remove the bitumin to allow you to use a cheaper leveller..... mate your asking professional advice so follow it or do tour own thing and cut corners and when it goes wrong moan to yourself about how you wish you listened !!!!!
OK what thickness of Ardex NA (is it Ardex or Arditex?) for both use cases: as a 'sealant' and a DPM sandwich?
