We live in a recently built house. Holes are appearing in the mastic at the bottom of one of the internal tiled shower walls, with brown staining coming out of the holes. Could this be the result of the tiles having been fixed with a non waterproof grout/adhesive?
Should tiles in a shower enclosure (and other places in a bathroom) be fixed with waterproof grout or adhesive? Is there an easy way of finding out what the builders used?
We are about to confront the builder about this problem and want as many facts as we can lay our hands on. Thanks.