Similarly, the installation of cement floors and damp-proof membranes can change the environmental conditions, forcing moisture into the walls that would otherwise have evaporated through the floors.
Yn yr un modd, gall gosod lloriau sment a philenni gwrthsefyll lleithder newid yr amodau amgylcheddol, gan orfodi lleithder i mewn i waliau a fyddai wedi anweddu drwy'r lloriau fel arall.