Will Sealing Grout in My Shower Stop Mold

The short answer is no. Sealing your grout will help to protect the grout and also make it easier to clean, but it does not change the environment. A shower / bathroom is obviously a wet area, with high levels of humidity – the perfect environment for mold to flourish. The best steps you can take to prolong the life of your grout and prevent mold build up are to use a quality grout and keep the area as well ventilated as possible.  Also, avoid the use of harsh chemicals and cleaners like bleach.