QUESTION

Mildew on Shower Floor Grout Surface - The grout on my shower floor has developed mildew and it keeps returning within a week after I clean it. What can I do to keep it away?

ANSWER

ANSWER - The mildew on the surface of the shower floor is an indication that perhaps water is trapped in the shower pan and is not able to escape to the drain, assuming you have adequate ventilation in your bathroom.   We commonly see where the installer does not properly presloped the shower pan substrate so the slope of the waterproof membrane is to the drain ¼” per foot and/or they don’t put weep hole protectors (gravel) around the drain on top of the membrane to keep those weep holes open for water to escape.  The only way to confirm this is to take the shower pan apart at the drain and at the corner of the shower pan.  Good Luck!