Why Caulk Type Matters in Wet Areas
Using paintable latex caulk in a shower is one of the most common DIY mistakes. Latex caulk shrinks as it cures and is not truly waterproof — within 6–12 months in a wet environment, it cracks, peels, and develops black mold behind it. The right caulk for bathrooms is 100% silicone or a siliconized latex hybrid specifically rated for wet areas.
Types of Caulk Explained
100% Silicone Caulk
The most waterproof and mold-resistant option. Bonds permanently to non-porous surfaces (tubs, tiles, glass). Extremely flexible — won't crack when surfaces expand and contract. Downsides: cannot be painted, harder to apply smoothly, requires mineral spirits for cleanup. Best for: shower surrounds, tub-to-tile joints, around fixtures.
Siliconized Latex (Latex + Silicone Blend)
Easier to apply and smooth than pure silicone, cleans up with water, and can be painted. Less flexible and less water-resistant than 100% silicone but dramatically better than plain latex. Best for: bathtub perimeters (if the tub is on a painted surface), around sinks, kitchen backsplash joints where you want to paint over it.
Paintable Latex Caulk
Do not use in wet areas. Fine for baseboards, crown molding, window trim, and interior gaps where it will be painted.
1. GE Sealants GE5070 Advanced Silicone — Best for Showers
GE's Advanced Silicone is the gold standard for shower and tub caulking. The formulation stays flexible for the life of your bathroom, resists mold and mildew (not just on the surface — throughout the caulk), and bonds to virtually every surface including fiberglass, acrylic, ceramic, and glass. Available in white, almond, and clear. A single tube handles a full shower surround with material to spare.
2. DAP 18286 Alex Flex — Best Siliconized for Painting
When you need to caulk around a tub surround where part of the joint will be painted, DAP Alex Flex is the right product. It's flexible enough to handle the movement between a tub and the wall without cracking, yet it accepts paint within 30 minutes. Cleans up with water before it cures.
3. Gorilla 8060002 Waterproof Caulk — Best All-Purpose
Gorilla's waterproof caulk is a reliable option for homeowners who want one caulk that works almost everywhere — tubs, windows, doors, and trim. It's 100% waterproof, paintable, and mold-resistant. Not as flexible as pure silicone but handles bathroom environments well for most homeowners who aren't professional tilers.
How to Apply Caulk Like a Pro
- Remove all old caulk completely with a caulk removal tool before applying new caulk — never caulk over caulk
- Clean and dry the surface thoroughly — moisture prevents adhesion
- Fill the tub with water before caulking the tub-to-tile joint — the tub will be heavier and lower when full, creating the gap at its maximum size. When the tub drains and rises, the caulk compresses instead of pulling apart
- Apply at a 45-degree angle in a single continuous bead
- Smooth immediately with a wet finger or caulk tool before it skins over
- Let cure 24 hours before exposing to water (48 hours for 100% silicone)