How to Caulk a Bathroom (Shower, Tub, and Sink)
By The DIYPicks Team · Updated July 2026
A clean, waterproof caulk line is what keeps water out of your walls and floor. The two things that make or break the job are choosing the right sealant and prepping the joint properly. This guide walks through picking silicone versus latex, removing the old bead, and tooling a smooth, long-lasting seal.
Choose the right sealant for each joint
For any joint that sits in constant water, such as a shower surround, tub edge, or sink, use a 100% silicone like GE Advanced Silicone 2. It is fully waterproof, stays flexible, and resists mold and mildew, which is exactly what a wet joint needs.
For painted trim, baseboards near the floor, or gaps you want to paint over, use a paintable acrylic-latex-plus-silicone like DAP Alex Plus. It cleans up with water and paints in about 30 minutes, but it is only water-resistant, so keep it out of the shower itself.
Remove the old caulk and clean the joint
Cut the old bead loose with a utility knife or a plastic caulk-removal tool and pull it out in strips. Scrape away every bit of residue, because new caulk will not bond well over old silicone.
Clean the joint with rubbing alcohol and let it dry completely. Any soap film, mold, or moisture left behind is the most common reason a fresh bead fails early.
Mask, cut the nozzle, and lay the bead
Apply painter's tape along both sides of the joint for a crisp edge, especially if you are new to caulking. Cut the tube nozzle at a 45-degree angle, making the opening about the width of the gap you are filling.
Hold the gun at a steady angle and squeeze with even pressure as you move along the joint in one continuous pass. A smooth, consistent motion beats stopping and starting.
Tool the bead and pull the tape
Smooth the bead with a caulk-finishing tool or a lightly dampened fingertip in one steady stroke to press it into the joint and create a concave surface. With silicone, keep a rag and some mineral spirits handy because it does not clean up with water.
Pull the painter's tape away immediately while the caulk is still wet, before it skins over, so the edges stay sharp instead of tearing.
Let it cure before water exposure
Give the sealant time to cure before exposing it to water. GE Advanced Silicone 2 is water-ready in about 30 minutes, but full cure takes around 24 hours, so waiting the full day when you can gives the most durable seal.
Ventilate the room while silicone cures, since it gives off a strong vinegar-like odor. Once fully cured, a properly tooled silicone joint should last for years before it needs replacing.
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Frequently Asked Questions
- Can I caulk over old caulk?
- It is not recommended. New caulk, especially silicone, bonds poorly over old silicone and traps moisture underneath. Always remove the old bead completely and clean the joint before applying fresh sealant.
- Silicone or latex for a bathroom?
- Use 100% silicone for wet joints like the shower, tub, and sink because it is fully waterproof and mold-resistant. Use paintable acrylic latex caulk for trim and drier areas you want to paint. Do not use latex caulk inside a shower.
- How long should caulk cure before showering?
- Check the tube, but a safe rule is to wait the full cure time. GE Advanced Silicone 2 is water-ready in about 30 minutes and fully cures in about 24 hours, so waiting a full day before heavy water exposure gives the best result.