How Do I Caulk a Bathtub?
Topics
- Caulk
- Bathtub
- Shower
- Silicone
- Waterproofing
Answer
Recaulking a tub is a 45-minute job that prevents serious water damage to your subfloor and walls. The number-one mistake: applying new caulk over old caulk instead of removing it first.
Remove the old caulk completely
Old caulk must come off entirely — applying over it creates a bond failure within 6–12 months. Use a caulk remover tool ($5) or a utility knife to score and lift the old caulk. For stubborn silicone caulk, apply a caulk softener product (Goo Gone Caulk Remover, etc.) and let it sit 2–3 hours before scraping. Wipe the joint clean with isopropyl alcohol and let dry completely — at least 24 hours before applying new caulk.
Choosing the right caulk
Use 100% silicone for tubs and shower enclosures — it's waterproof, flexible, and mold-resistant. Siliconized latex ("kitchen and bath" caulk) is easier to work with but less durable. Never use standard paintable latex caulk in a wet area.
Prep the tub
Fill the tub with water before caulking. The weight of the water flexes the tub to its "in-use" position. If you caulk with an empty tub, the joint will stretch when someone gets in and the caulk will crack within a few months.
Application technique
Cut the caulk tube tip at a 45° angle to create an opening about ¼ inch. Hold the gun at 45° and push (don't pull) the caulk into the joint in one smooth, continuous bead. Work the full length of each joint without stopping.
Smoothing
Wet your finger with water (or a mixture of water and dish soap). Run your finger along the bead in one smooth stroke, pressing the caulk into the joint and leaving a concave profile. Don't go back over sections you've already smoothed — this lifts the caulk.
Cure time
Let caulk cure 24 hours before using the tub or shower. Silicone needs contact with moisture to cure, so the bathroom doesn't need to be bone dry — but no standing water on the caulk.
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