Bathroom tile grout cracking — Delft, Zuid-Holland

Cracking grout between bathroom tiles may look minor, but it's the first line of defense against water penetration. Once grout fails, water seeps behind tiles and into the subfloor or wall cavity, leading to mold, rot, and structural damage that can cost thousands to repair. Shower and tub surrounds are especially vulnerable because they're wet daily. Common causes include normal aging, building settlement, missing expansion joints, incorrect grout type for the application, or cleaning with harsh acids that dissolve grout. A handyman can remove the old grout, treat any mold, and regrout the affected area in a day — a fraction of the cost of tearing out water-damaged walls.