I've found some dampness under the vinyl flooring in the hallway of my late
60s concrete-floored house.The concrete is still mostly covered with brittle brown tiles, and the concrete where exposed (missing bits of tiles) has some black stuff painted on it (or maybe it was the glue for the tiles).
The vinyl was put down temporarily a few months back (one day I'll put laminate down), but recently discovered a damp area underneath, together with white powdery stuff on the concrete, causing the floor to swell slightly.
What's the best way to deal with this? Someone I called out last year wanted to coat the entire ground floor for £400 (but I wasn't sure then if it was rising damp or a leak from somewhere). Would this work, or would any sort of coating just drive the moisture towards the walls?
Thanks.