Caulk vs Grout: When to Use Each

Grout and caulk look alike and do different jobs. Grout is a hard, cement or resin filler that locks tile in a flat plane. It does not stretch. Caulk is a flexible sealant that bridges joints that move: the corner where two walls meet, the line where tile meets a tub or countertop, around fixtures and at the edge of a floor. Using grout where caulk belongs is one of the most common causes of cracked joints and leaks.

For wet areas, silicone caulk is generally the best performer because it stays flexible and resists mildew, though it cannot be painted. Acrylic latex caulk is easier to apply and paintable but wears sooner. Urethane sealants are tough and used in some commercial settings. Old caulk should be fully removed before new is applied, because it will not bond to old residue. Replacing caulk every few years is normal maintenance, and a quick way to protect walls from water.

Best for

• Tub and shower corners
• Countertop and backsplash joints
• Floor-to-wall edges
• Anyone seeing cracked corner grout