How to Reseal Caulk Around Tubs and Windows

Caulk is your home's first line of defense against water intrusion — and in Florida, it fails faster than anywhere else. The combination of UV exposure, humidity, temperature swings, and constant moisture means caulk around tubs, showers, windows, and exterior penetrations needs attention every 2–3 years. Re-caulking is a low-cost, high-impact maintenance task that prevents expensive water damage and mold growth.

How Do I Know When Caulk Needs Replacing?

Inspect your caulk lines and look for:

• Cracks or gaps — even hairline cracks let water through
• Peeling or pulling away from the surface — the bond has failed
• Discoloration or mold — black spots in caulk are mold growing in or under the material
• Hardening — caulk should be slightly flexible; if it feels rigid and brittle, it has lost its seal
• Missing sections — areas where caulk has fallen out entirely

In Florida homes, the most critical caulk lines are around bathtubs and shower pans, at window frames (interior and exterior), around exterior doors, and where pipes or wires penetrate exterior walls.

How Do I Remove Old Caulk?

New caulk does not bond to old caulk — you must remove the old material completely for a lasting seal.

1. Soften the old caulk with a caulk removal spray (Goo Gone Caulk Remover works well) — apply and wait 30 minutes
2. Use a caulk removal tool (a $5 plastic scraper shaped to fit caulk joints) to pry and scrape the old caulk out
3. For stubborn silicone, use a razor scraper at a shallow angle — be careful not to scratch tile, fiberglass, or glass
4. Clean the joint with rubbing alcohol on a rag — this removes residue, oils, and soap film that prevent adhesion
5. Let the surface dry completely before applying new caulk

How Do I Apply New Caulk Like a Pro?

A clean, smooth caulk bead comes down to three things: the right caulk, the right cut, and the right technique.

1. Choose the right caulk — 100% silicone for wet areas (tubs, showers), siliconized acrylic for windows and trim (it is paintable)
2. Cut the tip at a 45-degree angle — start with a small opening; you can always cut it larger. A 1/8-inch opening is right for most interior caulk joints
3. Apply steady pressure — use a caulk gun with a smooth ratchet mechanism. Pull the gun along the joint (do not push) at a steady, even speed
4. Smooth immediately — run a wet finger or a caulk finishing tool along the bead within 30 seconds of application. One smooth pass, not multiple strokes
5. Clean up excess — wipe your finger on a damp paper towel between passes. For silicone, mineral spirits help clean smears on non-porous surfaces

What About Exterior Window Caulk?

Exterior caulk takes much more abuse than interior caulk — UV rays, rain, wind, and temperature swings all break it down. Use a high-quality exterior caulk rated for 25+ years (look for polyurethane or advanced siliconized formulas). Apply it around the window frame where it meets the siding or stucco, filling any gaps or cracks completely.

Do not caulk the bottom edge of a window — this is designed as a weep channel to let trapped water escape. Sealing it traps moisture behind the window and causes more damage than the gap itself.

Pro Tips for Better Caulk Results

• Fill the tub before caulking — the weight of the water pulls the tub down slightly. Caulk applied with the tub full will not crack when you take a bath
• Use painter's tape — tape both sides of the joint for a perfectly straight line, then pull the tape immediately after smoothing
• Do not over-caulk — more caulk is not better. A thin, properly bonded bead outperforms a thick glob every time
• Let it cure — silicone needs 24 hours before water exposure. Do not shower on a freshly caulked tub until the next day

If you would rather skip the caulk gun and have it done right in one visit, our light plumbing and handyman team handles caulk replacement throughout the home — tubs, windows, doors, and exterior seals. Contact us for a free estimate.