How to encapsulate asbestos bitumen coated concrete floor ready for new electric underfloor heating

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Hi,

Our house was built in 1983 and we have a 7m x 3m front room/dining room and want to install Warmup electric underfloor heating with laminate.

In my haste to get started, I ripped up the old carpet and underlay finding thin tiles that easily pried off the floor. Underneath the floor tiles was this black substance which I have since found out to be a very thin coating of bitumen used to stick the tiles down.

I have had the tiles and bitumen tested and they contain asbestos :!: The tiles have now been safely removed and disposed of properly. The floor has also been cleared of all dust and debris using an H class vacuum.

We want to start renovating the room but need to make the floor safe to walk on so not to scuff or scrape the asbestos bitumen floor that remains. What can we coat the floor with to make it safe to walk on and work on renovating the room?

Bare in mind that after we finish decorating the room we will be putting down underfloor heating. we have been advised the following floor setup:

Concrete floor
6mm notched troweled flexible, cement-based adhesive
Warmup 10mm insulating boards
Underlay
Warmup Foil heating
Laminate Flooring.

So we are looking for solutions that make the floor safe to walk on while we renovate the room while providing a suitable base to later put down flexible, cement-based adhesive to start working on our flooring plans.

I'm aware that the bitumen will cause potential issues with coating and adhesion but we are unable to remove it unless we pay a silly amount of money to get a company to grind it off safely.

One asbestos company suggested coating the floor with industrial floor paint but didn't indicate what type. Also, I fear that such paint may cause issues later when starting with our flooring plans.

Has anyone got some advice?

Thanks
Scott
 
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I believe the 'textbook' answer is Arditex NA (a self levelling compound which would serve as your 'flexible, cement-based adhesive'), since it is advertised as being compatible with bitumen residues and doesn't require a primer. But it will be expensive particularly at 6mm thickness. Someone more experienced might be able to suggest a cheaper alternative.
 
Temporary surface- hardboard.
Use gaffer tape under and over seams.
Shiny side up
 
Thank you both for your suggestions. together, both solutions work with what we are looking for.

Tigercubrider would 3mm high-density fibre board work? Found this: https://www.diy.com/departments/hig...sheet-th-3mm-w-1220mm-l-2440mm/1696257_BQ.prd but for 7Mx3M floor to cover that works out at just over £100 for a temporary covering seems a bit steep especially when afterwards I don't think we will have a need for it for anything else. Is there a cheaper alternative?

As for the Arditex NA. Looks like a great product and will do well to cover over the bitumen. Yes, it is pricey but it is still cheaper than getting a company in to grind off the bitumen and then priming the concrete left behind and then buying a cheaper flexible concrete adhesive. However, I would love to know if there is a cheaper alternative if it exists.

The Arditex NA specifies a 5m² coverage at 3mm thickness. Wouldnt a 6mm notched layer equate to 3mm smooth thickness? Or is the Arditex NA saying its thickness is also notched? Is 6mm notched specified by the manufacturer of the insulation boards absolutely necessary and 3mm notched would be enough??

Also looking at a competing underfloor system in their installation video of their insulation boards they say if using the foil matt the boards don't need to be fitted to a primed or adhesive surface:

Watch from 1:45

Does that mean we could just avoid the flexible cement adhesive altogether and lay the boards directly over the floor? After all, the floor is level and in good condition already.
 
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You be fine putting the Ardex na down at 3mm but you would still need to remove any loose adhesive.
The amount of asbestos in the adhesive will be less then 1% so I would worry too much.
 
When I removed cork tiles that had been stuck to concrete directly in one place, and stuck to plastic (?) floor tiles over bitumen in another, I used a scrapper. They had used contact type adhesive between the cork and surface.
I used a 6" telescopic Harris scrapper probably intended for wallpaper. I would guess ( unqualified) that in a DIY context doing it wet and wearing a mask would reduce any dust.
 
Sorry slight correction, I didn't read your first post properly even when I quoted it: The arditex isn't specified as an adhesive, it just gives you a level encapsulated subfloor. So 3mm as specified would be fine for that. You would probably use another product on top of that for sticking down the insulation if it actually needs to be stuck down (who knows arditex might work for this, but it doesn't seem like a very economical use of the product).
 
As the floor is unlikely to have a damp proof membrane under it - Synthaprufe (or Wickes equivalent), two heavy coats onto the bitumen then 'blind' with fine sand. Then the SLC.
 

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