With any area that is susceptible to high volumes of water, you want to make sure that all sealant and drainage potential have been addressed. As a niche creates a gap in the shower wall, you want to be certain that leaking isn’t an issue. Whether that means leaving a gap behind the niche cubby as mentioned above, or ensuring that you use high-quality grout, it’s important to not cut any corners in the design and installation process. If done properly, however, you’re golden.
