Somehow I have some dampness rising from where the floor slab/screed meets the wall. It is mainly on a patch of about 2 ft along in an internal 4 inch wall but there are one or two more places. I have stripped it back now and noticed that the carpet gripper seeems to have got damp corroding he spikes which in turn I guess is the cause of the carpet staining. the carpet seem. There are no services or water pipes anywhere near. The house is circa 1956 traditional build and I have attached some photos to show the carpet and the floor wall join and damp course exposed with the screed chiselled out. I had this tested by a reputable damp company and he could not find any damp and suggested it may just be caused an occassional capillary action when the water table is very high after heavy rain. The skirting boards are fine and no plaster is marked.

I thought it best to expose the area and put in a couple of coats of bitumous proofing from the existing damp course down the exposed bit of wall and across the concrete slab then re screed with a waterproofed SBR screed mix. Not sure though how far to apply the screed i.e. right up to the wal or leave a gap. Hopefully I have explained clearly enough with the photos to assist.

I would welcome any other views on the best course of action

What is the floor made from?

Is that dry?

_________________
DIY | Donnas dream house

The floor is made up in the traditional way with a concrete slab topped with 2 inches of screed. It is dry and no signs of damp or mould growth but felt a little damp when I put my finger against the wall brick below damp course but no real visible dampness creaping up.

That rules out my thought then!

I was thinking perhaps it might be asphalt and one of the fixings from the carpet gripper had penetrated it and was causing the problem!

_________________
DIY | Donnas dream house