Painting over Bitumen floor

Discussion in 'Painters' Talk' started by Macca73, Sep 2, 2021.

  1. Macca73

    Macca73 New Member

    93A7E1B7-9E10-42B9-A10D-CF4AD422CC35.jpeg Hi Guys, I recently removed some suspect (asbestos) floor tiles from my sons bedroom. They were safely removed using a scraper whilst wearing an Amazon purchased asbestos kit (White ET suits and face mask). This has left the floor With a black coating which is very thin and appears to be a bitumen type adhesive. I have heard that the adhesive may also contain a small amount of asbestos so would like to cover this.

    I intended to apply Ardex NA as a self levelling compound to cover the floor. However I have since found out (after buying the ardex Grr!) That the floor is not level and actually has a 6 cm drop from one end to the other over a 4 m span. Therefore using Ardex would not be appropriate because it was all Pool to one side and exceed the maximum depth of 3 cm anyway.

    My question is instead of SLC is there a paint that I could simply apply over the bitumen paint and patchy concrete bits that would seal the potentially dangerous adhesive and also not cause any issues safety wise in a child’s bedroom in terms of VOCs/emissions etc? Thanks in advance
    Last edited: Sep 2, 2021
  2. woodbutcherbower

    woodbutcherbower Well-Known Member

    A 60mm level drop over a 4m span isn't an insurmountable challenge. Return some of the Ardex for a refund, and stick with your original levelling plan. Put down an initial 40-50mm layer of fibre-added, thick-bed compound just in the dropped corner and feather it in towards the higher level. I use Mapei 3240 from our hosts, but other products are out there. This will get you in the 'almost flat' ballpark and stop the 'running downhill' problem you correctly allude to. Once set - level as normal using a regular thin-bed (10mm and below) leveller such as Mapei 1210 also available from out hosts. Quicker, easier, safer.
  3. Alem Keskic Keskic

    Alem Keskic Keskic New Member

    It is very important to choose the right adhesive. It is recommended to choose a material suitable for thick coating, with a high quality paint sprayer, repeated several times to cover the original floor evenly, it is time consuming but worth trying, it is important to note that after finishing make sure the paint is dry before moving around.
  4. Macca73

    Macca73 New Member

    Thanks for the quick replies.

    Woodbutcherbower - that's a good suggestion and one I initially discounted on the grounds of the floor to ceiling height being out by 6cm - the ceiling also slopes in line with the floor so by levelling the floor the ceiling would actually be closer to the floor by 6cm at one end comparted with the other - do you think this would be noticeable?

    If we went with this idea would the Arditex NA be suitable to go over the Mapei3240 product? This would save us buying a separate finishing layer.

    Thanks in advance!
  5. woodbutcherbower

    woodbutcherbower Well-Known Member

    You’re welcome. The eye tends to pick up horizontal lines at low levels - in other words a sloping floor is always going to be more noticeable than a sloping ceiling. A lot also depends on how the room’s going to be decorated - assuming a white ceiling, pale-coloured walls are going to make a 60mm ceiling fall imperceptible. A white ceiling next to a dark wall would probably be way more noticeable.

    And yes - Arditex NA latex will be absolutely fine on top of Mapei 3240. Hope all goes well.
  6. Macca73

    Macca73 New Member

    Thanks for coming back woodbutcherbower.

    I’ll more than likely go with that approach. Just waiting to hear back from Ardex about one of their products which will be similar to Mapei 3240 then I’ll pick one of them and run with it.

    I reckon I’ll need to paint on a damp proof layer too as the old tile floor performed that task I think before it’s removal.

  7. woodbutcherbower

    woodbutcherbower Well-Known Member

    I'm sure there will be something suitable in their range. The thicker-bed compounds contain fibres to beef them up and strengthen them. Best primer to use is SBR. Damp-proofing - what's the final flooring going to be?
    Macca73 likes this.
  8. Macca73

    Macca73 New Member

    Hi again - the final floor will have underlay and be carpeted. I’m hoping the Ardex DPM1C will be okay in top of the Arditex NA?

    Ardex say there is no need for a primer with Arditex NA. However would you recommend one on the old floor before applying the thicker bed compound?

    Thanks again you’ve been really helpful
  9. woodbutcherbower

    woodbutcherbower Well-Known Member

    No problem at all. For underlay and carpet - all you need is vapour barrier sheet under the underlay - it's cheap to buy, and assuming you've given the SLC plenty of time to thoroughly dry. Bear in mind that because the SLC is going to be pretty thick at the lower level of the slope, the top surface will look dry well before the material underneath it. I'd give it a least a week before you put down your carpet.

    Primer - it was actually the old floor I suggested you prime with SBR first. From what you say, I don't think that anyone could hazard a real guess at what's actually down there, so a decent primer will seal it all in and provide a new, unreactive surface to put your compound on. It's all about that initial bond between old and new surfaces, and a good primer is the best solution.
  10. Macca73

    Macca73 New Member

    Great thanks it sounds like we have the makings of a plan - extremely helpful!

    I will await a reply from the Ardex technical support man who will reply on Monday now I expect. Then I can decide on the compound and take it from there - have a great weekend and thanks again
  11. Macca73

    Macca73 New Member

    Hi Woodbutcherblow - The Ardex man came back and urged caution about going greater than 36mm over a bitumen covered floor in case it fails. He suggested applying the NA over the entire floor but take a cup of latex out of the bottle to stiffen the mix first. I am not 100% convinced it will work as the vids show how quickly this stuff flows. I guess worst case scenario the entire floor gets some form of coating (albeit with the higher end of the room almost receiving what would effectively be a painted layer once it levels and the floor will be in a better position than it is currently. He also suggested painting Ardex DPM1C over the NA as the finished surface to make damp proof. If it works this sounds like the simplest solution but not convinced - its a tricky one!

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