Concrete floor with bitumen paint - more bitumen or seal ?

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Hello,
Just bought a house which I'm now in the process of gutting.
Just removed the floor in the sitting room (had laminate laid on carpet underlay....laid on "asbestos" tiles).

All that has now gone - smells a tad damp, but that could be the underlay sweating between the laminate and tiles ?

Anyway, I'm now down to the concrete and there is a layer of bitumen paint. Should I go over the floor with another layer of paint to help with possible damp, or should I seal with acrylic primer?

This room will be carpeted. The other rooms will either be tiled or vinyl flooring - so possible SLC required as well.

Thanks in advance.
 
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myuserid, good evening.

Like your board name by the way?

What you describe, Asbestos tile stuck down on to Bituminous "Paint"?

This form of construction was very common in the 50s and early 60s especially in Local Authority properties, the "Bitumen" was generally a layer of this material not simply a painted on layer, which begs the question? was there a 10.mm or so layer of Bitumen in place or was it simply a layer of painted on damp proofing paint ?

Kicker is that the layer of Painted on or approximately 10. mm thick layer of Bitumen was and is the Damp proof membrane for the floor [hence the smell of musty dampness in the room??]

Question? is it a layer of bitumen paint or? was there a layer of bitumen that has been removed with the Asbestos tiles?

Sorry no direct answer to your question posed, sorry but not sufficient information around the thickness of the Bitumen, paint or an actual layer of Bitumen??

Ken
 
Hi Ken,
Thanks for the response.
The bitumen is less than a millimetre thick - painted on by all accounts. Tiles came up very easily with zero bitumen attached. I'm not 100% convinced they are asbestos tiles - but I best err on the side of caution. I have attached a photo after removal.
There is a DPM which I can see 3-4 bricks above ground level (it is an ex council house).

IMG_8478.JPG
 
myuserid, good evening again.

OK Back in the day, Asphalt, generally about 10.mm thick was used as the Damp proof membrane.

In your Property, it appears that, there is a layer of painted on bituminous paint.

At times then Bituminous paint was used to stick down the tiles [Thermoplastic type] meaning they had to be heated prior to laying [ a messy process I recall well]

But as far as I can see in the Image posted, your floor had a layer of lighter material applied and it is that lighter material that appears to have been the glue for the tiles? --- the lighter material has serrations indicative of a serrated trowel mark --- used to spread adhesive for tiles.

Decision time?? is the Bituminous paint a DPM or not?

i would err on the side of Caution, in that I would find a compatible DPM Paint and apply that [Caution, the material applied back in the day may? react with modern materials --- Proceed with Caution, test small areas?]

Next But, is that, you are to lay a Carpet, if you lay carpet direct on to Bituminous paint, the Carpet will stick. hard?

Ken.
 
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See this all the time.
Grind / scrape off as much as the old adhesive as possible.
Then either 2 coats of uzin PE404 dpm then prime and Screeding compound
Or
Ardex NA
Ardex dpm 1c
Prime
Ardex NA
 
Thanks for the replies. Looks like the bitumen stuff was used as an adhesive ?
Had a better look today and the trowel marks are in the "bitumen" and not to the edge.

Got to admit - I'm leaning towards sealing what is there and using SLC. Pain in the rear - but may as well be done right first time round.

IMG_8491.JPG
 
myuserid, good evening again.

Question? can you recall what colour the adhesive was on the rear of the tiles now removed?

If Black then [Sorted] in that, back in the day the tiles, Thermo-Plastic were stuck down with liquid Bitumen type material, the tiles were "heated" prior to being stuck down?

Really positive aspect of your floor is that the Bitumen is painted or troweled on rather than being about 10.mm thick, if the latter then that layer would be the Damp Proof Course [and a pain to repair]

On a different front, in the [very helpful last image ] posted, is that a Damp Proof Membrane at the interface of the floor slab and the wall? there appears to be a black material rising vertically up the face of the inner course of the wall?

Ken.
 
Hello again.
Finally made it over to the property to take a look.
The tiles just have black "bitumen" on the back.
The "black material" you see is actually clear plastic sheet - which I presume is the DPM ?

So - how should I go about this. Should I use a paint/seal suitable for bitumen and then carpet ? Or should I seal/create another DPM and run SLC throughout.

The reason why I have mentioned SLC - in the hallway and kitchen tiles have been laid directly on top of the bitumen. Of course these have now started to lift!
I have started to remove the tiles and now chipping away at the remaining tile adhesive but this floor is never going to be super smooth unless SLC is used (hallway and kitchen will be either tiled or vinyl) ?

Many thanks for your help.

IMG_8740.JPG


IMG_8741.JPG
 
Hi, I'm still in the process of rectifying my house of 1947 period ex local authority house. I made mistake of digging further to remove top layer of screed too. I had a lot of sitting water under mine however.

There is no dpm as the tiles and the glue was. As pointed out before. In 1950s there was open fires and draughty windows so it was ventilated enough to prevent moisture build up. Also carpets weren't wall to wall, generally.

Not done mine yet as I've got 25mm to make back up and that is expensive in Ardex or similar.

Just wanted to confirm what you have. Can't offer any other advice.
 
Hi, first post here as I'm also in the process of trying to sort out my floor which is in an similar situation to yours and Bowlzi.

I thought it might be worth mentioning: In my situation, the tiles were positively identified as containing asbestos, as was the black bitumen mastic that was used to stick the tiles to the screed below the tiles. As such, I decided not to grind off the mastic/bitumen (the Asbestos identified was Chrostyle in both cases, and expected to be low risk and low percentage present).

I also noticed you have a gap between the top screed and your wall base in this pic:
img_8491-jpg.124521


Question for anyone really: If you are going to apply some sort of liquid based DPM (e.g. Ardex) - or SLC and then DPM, how would you deal with this gap? Would you fill it first (e.g. SLC or concrete?), or just let the DPM/SLC fill it?

I would expect a DPM layer to be most effective if it meets the DPC in the wall (which I am guessing that's the DPC in the wall in the pic), so some way to fill the gap to make this possible would be best? However I've no idea if this gap is there to allow the base to expand or some other reason.

Bowlzi: I'm in the same boat as you, I've removed the screed layer as it was badly damaged by the damp (and removal would release less asbestos fibres than grinding). I expect you've reached a concrete base with no evidence of a DPM below that? I don't have the water sitting on mine but would like to install some form of DPM (currently looking at Ardex DPM), then screed over.
 
You can't apply the dpm to the old adhesive residue so either -

Grind off old adhesive then dpm , prime , screed
Or

Ardex NA , DPM1c , prime , Ardex NA

We lay it up the wall a inch as well
 
Think I'm just going to run some Ardex NA over the bitumen and be done with it. I'm fairly sure there is a DPM in place looking at it both externally and internally. The concrete slab is also dry. This will be a rental - so can't spend £1000 on SLC and DPM. If issues arise in the future I will use DPM1c followed by another layer of Ardex.

P.Pipe - your question is a good one re the gap between slab and wall. I will silicone it up prior to laying the SLC. No point wasting expensive compounds!
 
Hi,
There is no membrane beneath your floor or any others of this period. The damp course will exist in the walls only. The marley tiles and bitumen acted as a dpm of sorts.
Pity you took the screed off as, like me, you have an inch to build back up. Look at my posts and you may see images of mine.
Did you have a damp problem showing in floor or walls or did you just want to remove tiles.
If you are only going to put the ardex na on then only buy a cheap floor if you plan to lay wood down.
Any other floors i would leave alone now unless i had major issues.
 
Last edited:
Hi Bowlzi - I haven't taken the screed off. What you see is what is left after the tiles came up - less than 1mm bitumen type stuff. There aren't any damp issues either apart from a musty smell which may have been the layers of crappy flooring laid over the concrete!
Sounds like there are two types of flooring used - those which have a thick layer of bitumen with tiles on top and those with a DPM underneath the base and a thin layer on bitumen which acts as an adhesive for the tiles ?
I'm fairly confident there is a DPM - you can see it externally and follow internally then underneath the floor. I will take pics tomorrow.

Pain in the rear all this stuff anyway!!...and expensive!
 
Question for anyone really: If you are going to apply some sort of liquid based DPM (e.g. Ardex) - or SLC and then DPM, how would you deal with this gap? Would you fill it first (e.g. SLC or concrete?), or just let the DPM/SLC fill it?
what I do it go round and fill any holes with silicon might not be the best way but work for me regards david
 

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