1950’s ex council - Knocking through from kitchen to dining room. All the worktops are out so one of the final steps was I had my asbestos guy out to remove the lino which was under both rooms floors (tested positive for asbestos). Unfortunately under that we found more problem flooring 🫠 (I know these systems often also contain asbestos) 

Kitchen has what looks to be a 1” concrete screed poured over the original concrete with the adhesive remnants of asbestos tiles on top. My guy removed about 2 or 3 half tiles along the perimeter where the previous owners clearly couldn’t get to, under the units maybe. There are two patches where they didn’t tile, or did a different system - what we suspect to be an old pantry/downstairs toilet and by the sink. There was a brown paper backing over all of the adhesive area which we assume was to prevent the lino sticking? That’s been removed mostly.  
This is either has no DPM under or the same bitumen felt used in the DPC(visible at the gap between the two rooms but could just be for the dividing walls DPC). Screed stops a touch before the masonry and was plastered down below so bridging. 

Dining room has a practically flawless maybe 15-20mm of bitumen-asphalt(dark brown), then under this a very strange layer, black bituminous ish mixed which some large fibrous material. There are areas where neither are(hearth and room gap), and the edges of the system have broken. There’s also the gap between the two rooms where you can see the build up of both systems. This system comes up easily. Few taps with a screw driver underneath and the whole thing lifts and breaks leaving effectively no residue. Not rippped off skirting yet so unsure if this is bridging too. (Asbestos test pending) 

There was a mad amount of salt excreted over the first night following removal of lino, over this crack, so we know there’s no effective DPM in this area. 

Hive mind I need help on two fronts:

**Identification** \- help me confirm what we have!

**Action plan(we want both rooms tiled with UFH):** 

Rip up - can’t be sure how easy the kitchen would come up, I hope it’s on bitumen felt as it would just lift. Dining room would be up easy, all would be double-bagged as asbestos waste. Gaining floor height would mean we could spec more insulation for UFH? We don’t want to rip up the whole screed underneath it’s not worth it. I already know that in many scenarios these systems (not sure about kitchen) were used as a DPM. So if we remove it we’d need to reinstate something, a liquid system like tanking slurry? Then self-leveler, insulation and another thin screed or cement board? Then tiled finish. The two systems are at different heights so the idea of reinstating them back to their shared conc height seems attractive. Given there would already be significant work to reinstate a DPM where it’s failed/there isn’t one, why not just scrap the shit. And get a better UFH build up. 

Screed over - I’ve read every forum post/article on the dining room system I can find and most suggest screeding over with Ardex. If I understand correctly this doesn’t function as a DPM though, only a primer and SLC that is compatible with bitumen. So I’d still need to patch up the failed/absent DPM areas. And even then what about the blank patches of conc of which I don’t know their build up (the suspected pantry patch is visibly mouldy and behind the cupboard on it is under the stairs which is base conc and had an unholy amount of salt all over it when we moved in). This feels like a bodge n forget job, I don’t want a failed system in years to come because of damp lifting /movement.

I know something similar runs under the hallway carpet (behind that closed door) so we’d probably also do that. 

Bitumen-asphalt, some weird tar fibre layer underneath & an even higher slab with bitumen asbestos adhesive next door - rip it all up?