I'm not sure this is a plumbing question, but can I install a niche in the wall above the shower head in my bathroom? My contractor seems to think not, that the niche would be too high to wipe out and keep dry, and even if the floor of the niche were canted any condensation would collect and cause rot to the underlying framing wood behind the shower wall. I don't know why that would be true if the area were properly water barriered like the rest of the shower walls, but can't find any info online about positioning a niche in this area. Can anyone give some advice here? Thanks.