Does anyone know what this stuff is under my carpet?

[PositiveLife]

So, normally I'd expect there to be underlay, gripper rod and carpet on top of the floor. However mine seems to have extra layers - there's some thin stuff that is under the underlay. In places it seems to be nailed in. It snaps fairly easily but has a little flexibility. Google has not been my friend so I thought I'd try here .

I only found it because one of the alcoves has a higher bit than the rest of the room and I was trying to find out why. Someone help before I end up pulling the whole thing up and having a lockdown DIY disaster!

Be careful. I think that could be asbestos. I'm not a professional or anything though but please do some more research before messing about with it.

I'm thinking it might be a bit like old lino? Could perhaps have been there partly as insulation?? Not at all sure but something about your picture looks familiar to me. I'll update if I think of anything more!

It looks like asphalt, fairly common in houses built between the 40s and 60s if that fits?

House is 1900s but obviously could have had various things done over the years

DH says it looks like some sort of bitumen layer probably for insulation. He says it's not dangerous. It's common in houses from 30s or 40s.

Definitely asphalt, DS had it in his doer upper. Screeded right over it then laid vinyl tiles.

I think it is bitumen too. I have it on the floors of my 1st floor flat built in the 1950s