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.
