The garage in my 1936 build house has an old concrete floor with no sign of a DPM. It looks to have been extended and patched over the years, so it's a little rough and wonky in places. While I haven't ever seen any pooling water, there is a damp feel in general and anything that gets left on the floor seems to have a moist patch under it within a few days, which I'm sure is a sign of an absent or failed DPM.
I am planning on using it as a gym eventually, potentially with a rubber floor. However, I want to address the lack of DPM before continuing.
I've seen some suggestion to lay a 1200g DPM straight onto the concrete, lapped up over the existing DPC. But I am concerned this would lead to water pooling below the DPM with nowhere to go, potentially migrating where it's not wanted.
Another suggestion is to lay a screed on top of the concrete. I have at least a few centimetres to play with so this is a possibility, and it would hopefully iron out the imperfections. Only thing I'm not sure about is whether screed itself can be damp proof or if it would need a DPM below it?
I'd like to avoid digging up the existing concrete if possible.
I am planning on using it as a gym eventually, potentially with a rubber floor. However, I want to address the lack of DPM before continuing.
I've seen some suggestion to lay a 1200g DPM straight onto the concrete, lapped up over the existing DPC. But I am concerned this would lead to water pooling below the DPM with nowhere to go, potentially migrating where it's not wanted.
Another suggestion is to lay a screed on top of the concrete. I have at least a few centimetres to play with so this is a possibility, and it would hopefully iron out the imperfections. Only thing I'm not sure about is whether screed itself can be damp proof or if it would need a DPM below it?
I'd like to avoid digging up the existing concrete if possible.