Hi all,
I’ve been getting damp coming through the dots/dabs behind the plasterboard in a section that was previously an outer wall.
As in the photos, we previously had a 1st floor walkway between our house and garage and we had builders create an indoor space at ground level below, involving putting in a small pitched roof section (with skylight) under which is an exterior door.
However, since the work was done, the plaster is damp to the touch which seems to be transferring from the old exterior wall behind. You can see the damp and mouldy spots in the pictures.
The damp only seems to be on one side (not on the old exterior garage wall) . I asked another builder what they thought and they said I should look into whether it is rising damp or coming from above (eg a leak in the flashing). But I’m not really sure how to do this (eg if I cut the plaster away how will I diagnose the issue) or what the solution would be.
Any advice would be gratefully received. I imagine dot and dab was used instead of batons because there is only just enough width for the external door.
In case it helps, we had a concrete screed poured on the ground with a waterproof membrane beneath.
Thanks