Tar layer under the floor Help, advice, information, answers and tips on all types of flooring from laminate and carpet to timber and vinyl

[goose]

I've just removed the carpet and underlay from a room (its was there when bought the house). the floor is 'oily' I noticed in a patch where the concrete was broken around the fireplace that there appears to be a tar impregnated fibre layer under the concrete - I'm guessing this is 1950's damp proofing. (the floor appears to be made of a concrete base then a tar layer then a (i guess) a self leveling concrete type layer)).

In the alcoves the floor is lower than the rest of the room.

Is it better to removed the 'level layer' which sits ontop of the tar or try and seal the floor?

(Its the same in the front room of the house)

thanks,

[goose]

To add to the above, I'm knocking the plaster off the walls, but if I lay a new floor should I lay it as close to the brick wall as possible? or to the 'old plaster line'?

many thanks,

[goose]

anyone? please!