floor with tar like residue- self levelling compound suitable?

P

Petal

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Folks,

I've taken up the old floorboards and thought I'd find a reasonable ok concrete floor underneath. However, what we did find was some very patchy floor with this old tar like black stinking stuff. I had some gas people in (for the boiler) and they said i should polybond the floor and then pour self levelling compound onto it. The floor is not massively uneven, but has a good bit of mountain valley thing going on. Is the above approach suitable?

I was then going to put down a plastic moisture barrier, followed by WPB boards but the shop delivered normal ones - should I exchange? And then secretnail the solid oak down.

Re the boards, I need to nail them into the concrete floor thereby piercing the dampproof plastic linining, is that ok? Sorryfor such stupid questions, but I really just don't know....

Many thanks for all help...
 
Hi Petal, don't nail the floor into concrete, nail it into the ply. You'll destroy the sub floor and probably the nailer by trying to nail into the sub floor. Also, no point puting down a membrane if you're going to pierce it.

Are you sure the ply you got isn't WBP (water and boil proof)? Most of the standard stuff is, perhaps you were thinking of marine ply, which would be overkill.

The black tar stuff is probably bitumen, the bonding sounds like a viable solution if there isn't huge amounts of it.
Leo
 
Hi Leo, no I'm planning to put polybond on the floor, then the membrane,then the plywood and the wood nailed to the plywood. I'm just wondering about nailing the plywood to the conrete floor, which would pierce the membrane... And the plywood is shutterboard or something (hope splled right)...
 
Do you know if the floor has a dpm? If it doesn't, you may have to float the floor over the dpm, making sure you don't puncture it.

Take a look at this and [broken link removed] for some good advice.
Leo
 
No don't think so. The house is an old council house from the 60s.

What I was told was that I should put a heave gauge plastic membrane down, put WPB over it and nail the floor to the plyboard. Can I not do that? I was always wondering about nailing the WPB to the concrete as you would have to nail though the plastic membrane, but if you use WPB the damp shouldn't really rise then, should it? The floor doesn't seem wet anyway, and there's no smell of damp at all...
 
Where you fix the ply will be a weak points, so perhaps you could fill/cover these with polybond as well.
 
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