Basement Stone Floor / Bitumen

[incrediblechunk]

So, after starting a job today it soon turned into something else so thought I'd get the views of people on here. I live in a 1840's stone built end terrace. The previous owner has converted the basement but it leaks and the walls are often damp so it clearly hasn't worked. I'd love to rip everything out and start again but that's beyond budget at the moment. Accepting I get leaks, from common streaks of water across the floor to a couple of times a half inch of water, I decided I'd like to make the room a bit more usable (currently bare floors) as the original carpet was a mess and so have left it bare since removing it. My plan was to paint the edge of the floor and then adhere a rubber bead to divert any incoming water to the low point (the floor slopes). In starting, I pulled up some skirting and up came the floor with it, turns out not to be concrete but a thin layer of bitumen laid over original stone flags (with what appears to be a layer of grit sand beneath). I'd like to rip up all of the bitumen, remove the grit sand, clean and seal the stones. What I wondered am I likely to be letting myself into a world of pain, or should I accept the water will come through anyway and go with my preferred stone floor? I've attached a picture to give you an idea of what I am talking about. Thoughts anyone?

 

[bobasd]

something very similar was posted recently. why not search for it.

what you propose wont work.

you show asphalt over stone flags - there's no membrane (DPM) under the flags. The asphalt was the membrane.
the asphalt would prevent the damp coming through in one place and direct it to another - often at the edges or up the wall as rising damp.

Best practice says:
lift all the flags - dont damage them - after marking them for position with crayon, and making a map. then clean them off ready for re-laying.
have the walls been dot and dabbed?
dont go sealing the stones with anything until you have a good understanding of the cons - there are many.

there's not all that much you can actually do without waterproofing the floor below the flags and tanking the walls - and there are whole sites dealing with these issues and masses of threads on here.

 

[incrediblechunk]

Many thanks for your response bobasd.

I did have a search through threads and read plenty but didn't find one that related closely enough so thought I'd post something. I'll have another search and see what I can find.

The original stone walls have all got stud walls to the inside now, having got down on my knees there does appear to be some membrane going behind the stud wall from the edge of the asphalt, but I can now view down the stud from the top in places and can't see anything so not sure it goes very far up and I do get damp patches on the walls unless I constantly dehumidify so clearly not functioning as it should.

Thanks for the advice on the stones, I'll have a search on here about the cons of sealing stone, I hadn't appreciated there were any.

I'm hoping I haven't opened up a world of pain for myself by removing some of the asphalt but it was done initially by accident and it wasn't doing it's job as I do get water down there, I'm just hoping that it wasn't doing a part job and I've just made myself a new paddling pool. Thanks again and any more thoughts from anyone are welcome and in the meantime I'll have another search.

 

[bobasd]

it might pay you to cut a panel of plasterboard 1200mm x 300mm from the base of the wall and examine whats behind.
cut a level line and centre your vertical cuts on studs - use a knife.

why have asphalt if there's a membrane already below the stones?
what you can see might be a lapped up edge of a DPM sheet - or it could be something to do with "tanking" or a vapour barrier behind the stud wall?

 

[incrediblechunk]

Apologies, I've not explained the membrane bit very well. The asphalt has been laid on top of the stones (on top of grit sand) and then at the edges, next to the wall, it appears to run into a membrane that disappears up behind the stud, so the membrane starts where the asphalt stops and I presume there is some bond between the two. I've done plenty of reading this afternoon though am yet to get too deep into the cons of sealing stones. Still not sure what my next plan of attack is, it wouldn't be too late to find something equivalent to the asphalt to lay back and leave as is, but my sense of adventure makes me want to remove it all and get back to the original stones, possibly in the future removing the stud walls, then rebuilding including a drained cavity with sump pump to deal with any incoming water from the walls.