If you have a tiled bath, check the caulk bead along the top edge of the tub or shower pan; if it’s cracked or missing, water can seep behind the tiles and destroy the wall. Here’s an easy way to apply a new bead: First, dig out all the old caulk with a thin-bladed screwdriver or putty knife. Brush out any dust or debris and allow the open joint to dry. Then apply two straight, parallel strips of masking tape — one on the tiled wall, the other along the top edge of the tub.
Squeeze a thick bead of caulk into the joint and force it into the crack with a wet fingertip. Wipe off your finger, wet it again, and smooth out the caulk. Then carefully peel off the tape strips to reveal a neat, straight bead.
Pro Tip: This Old House general contractor Tom Silva recommends using a 5-in-1 painter’s tool and a razor scraper to slice away old caulk with quick, sharp strokes. After removing the bulk of it, scour away every trace of residue with a dry, nonabrasive pad, then wipe the joint with a damp cotton rag to remove caulk dust. Thoroughly dry the area with paper towels, a dry rag, or a hair dryer before applying new caulk.
Be sure to use a mildew-resistant acrylic-latex sealant formulated for bathrooms rather than silicone. As noted in This Old House Magazine, acrylic latex will be much easier to replace than silicone when the time comes—and silicone residue requires scrubbing with mineral spirits, which can scratch plastic tubs and surrounds.
