The internal mains stop-cock is located in the hall ~6m from the damp patch.
After wrapping every water-pipe joint in the garage with paper towel and seeing no sign of dampness, I'm now 99.9% sure that the source of water is below the garage floor.
I made a close inspection of the edge of the concrete garage floor but did not find any sign of a membrane coming from under the concrete to meet with the wall dpc, which is about 1" above the concrete, therefore, I now believe that water is wicking up between the wall and edge of the concrete, then spreading out through the concrete from that point. The challenge now is to find the source of the underground water!
Operations are now suspended for a week until our guests leave but I then intend to chisel out an inspection hole in the dampest part of the floor.
I'll report back on what I find.
After wrapping every water-pipe joint in the garage with paper towel and seeing no sign of dampness, I'm now 99.9% sure that the source of water is below the garage floor.
I made a close inspection of the edge of the concrete garage floor but did not find any sign of a membrane coming from under the concrete to meet with the wall dpc, which is about 1" above the concrete, therefore, I now believe that water is wicking up between the wall and edge of the concrete, then spreading out through the concrete from that point. The challenge now is to find the source of the underground water!
Operations are now suspended for a week until our guests leave but I then intend to chisel out an inspection hole in the dampest part of the floor.
I'll report back on what I find.