How to Fix a Running Toilet in 4 Simple Steps
Find out how to fix a running toilet by checking the flapper, fill valve and float. Stop wasting water and cut your bill.
Knowing how to caulk a bathtub protects your bathroom from water damage and mold. Caulk seals the joint between the tub and the wall. Over time, it cracks, shrinks or turns moldy. When that happens, water seeps behind the tile and rots the wall. A fresh bead takes one afternoon and costs less than ten dollars.
When Should You Recaulk?
Look for these warning signs.
- Cracked, peeling or gapped caulk
- Black or pink mold that will not wash off
- Caulk that has lost its flexibility
- Water stains or soft spots around the tub
Tools and Materials
- 100 percent silicone caulk labeled for kitchens and baths
- Caulk gun
- Caulk removal tool or utility knife
- Rubbing alcohol
- Painter’s tape
- Rags and a plastic spoon, optional
- Gloves
How to Caulk a Bathtub Step by Step
1. Remove the Old Caulk
Score along the top and bottom of the old bead with a utility knife. Then peel it away with a removal tool. Scrape any leftovers with a plastic putty knife. Avoid scratching the tub surface.
2. Clean the Joint
Scrub the gap with a brush and a cleaner that kills mildew. For mold tips, read how to get rid of mold in the bathroom. Wipe with rubbing alcohol to remove soap film. Then let the area dry for at least 24 hours. Moisture under the new caulk causes it to fail.
3. Fill the Tub With Water
Fill the tub with water before caulking. The weight opens the gap to its widest position. As a result, the caulk will not pull apart when the tub fills later.
4. Tape for Clean Lines
Apply painter’s tape about one-eighth inch above and below the joint. This step creates sharp, professional lines.
5. Cut the Nozzle
Cut the tip of the caulk tube at a 45-degree angle. Make the opening small, about one-eighth inch. You can always cut more later.
6. Apply the Bead
Hold the gun at a steady angle and squeeze while moving along the joint. Keep a continuous, even bead. Work in sections of a few feet.
7. Smooth the Caulk
Wet your finger or use a caulk tool to smooth the bead. Press lightly to push caulk into the gap. Wipe off excess immediately.
8. Remove the Tape
Peel the tape off slowly before the caulk skins over. Pull at a shallow angle away from the bead.
9. Let It Cure
Follow the label, usually 24 hours, before using the tub. Keep the area dry during that time.
Tips for a Better Seal
- Choose silicone, because it resists water and mold
- Work in a ventilated room
- Do not paint silicone caulk
- Replace caulk every 3 to 5 years
The Family Handyman and other experts often recommend practicing on cardboard first. The Consumer Product Safety Commission also shares safe ventilation advice on its official website.
If you prefer a full refresh, learn how to clean grout on the surrounding tile.
Final Thoughts
You now know how to caulk a bathtub like a pro. Remove the old bead, clean and dry the joint, then apply and smooth fresh silicone. A good seal keeps your bathroom dry and mold-free for years.