I bought a house with a musty damp smell.
2 damp specialists said my walls were dry and the smell was condensation. I left all the windows and doors open for a few weeks, cleared the house of all flooring etc and put down plastic sheeting everywhere both as a moisture and a dust barrier.
Pulling back the sheeting in the living room last week the concrete slab has large and small patches of wet black mould and water sitting on certain patches.
There is no dampness spreading up the walls as the edges of the floor are dry.
This is what it was like when I initially took the flooring up but thought I had dried it out before laying the sheeting.
I am guessing the dpm has roger failed in the middle
or could it be sweating concrete
or condensation
or the fact that the outside soil levels are slightly above the dpc and floor level?
Or a combination of some or all of the above