Silicone sealant is the finishing touch on almost every plumbing installation — around tub and shower surrounds, at sink bases, around toilet bases, and anywhere water could work its way behind a fixture. Using the wrong sealant or applying it incorrectly leads to mold, water damage, and failed seals within months. Here’s what actually holds up.
| Product | Best For | Price |
|---|---|---|
| GE Sealants GE5070 Kitchen & Bath Silicone | Best Overall | ~$8 |
| DAP 18401 Kwik Seal Plus | Best for Tubs & Showers | ~$7 |
| Gorilla 100% Silicone Sealant | Best Heavy Duty | ~$10 |
Best Overall: GE Sealants GE5070 Kitchen & Bath Silicone
GE’s kitchen and bath silicone is 100% silicone — not silicone-latex hybrid — which means it doesn’t shrink, doesn’t crack in temperature changes, and holds its seal indefinitely in wet environments. It’s mold and mildew resistant and paintable after curing. I use GE or equivalent 100% silicone on professional jobs and it’s what I recommend to homeowners.
- ✅ 100% silicone — no shrinking or cracking
- ✅ Mold and mildew resistant
- ✅ Paintable after cure
- ✅ Adheres to tile, porcelain, glass, metal
- ❌ Takes 24 hours to fully cure
Best for Tubs & Showers: DAP Kwik Seal Plus
DAP’s Kwik Seal Plus is specifically formulated for the high-humidity, frequently wet environment of tubs and showers. The siliconized acrylic formula is easier to tool (shape with a wet finger) than pure silicone, and it remains flexible long-term. Strong mold resistance and fast cure time — touch-dry in 2–4 hours.
- ✅ Easier to apply and tool than pure silicone
- ✅ Fast touch-dry time
- ✅ Strong mold resistance
- ✅ Good for caulking around tub deck and shower pan
- ❌ Not as durable as 100% silicone long-term
Best Heavy Duty: Gorilla 100% Silicone Sealant
Gorilla’s silicone is their strongest formulation — waterproof, temperature-resistant from -65°F to 400°F, and excellent adhesion to virtually any material. Ideal for areas that get extreme temperature swings (around water heaters, near exterior walls) or where you need a permanent bond.
- ✅ Extreme temperature range
- ✅ Permanent bond — very difficult to remove
- ✅ Works on any material
- ❌ Clear only — limited color options
How to Apply Silicone Sealant Correctly
- Remove all old sealant completely — use a utility knife and silicone remover. New sealant won’t bond over old.
- Clean the surface with rubbing alcohol and let it dry completely.
- Apply painter’s tape on both sides of the joint for a clean line.
- Cut the caulk tube nozzle at a 45-degree angle — small opening for thin joints, larger for wide gaps.
- Apply in one smooth continuous bead.
- Wet your finger with soapy water and smooth the bead in one pass.
- Remove the tape immediately before the sealant skins.
- Allow to cure fully before exposing to water.
Plumber’s tip: The most common mistake is applying new sealant over old. It won’t stick and it’ll fail within months. Remove everything first, even if it takes an hour.
FAQ
What’s the difference between caulk and silicone?
“Caulk” is a general term for gap-filling sealants. Silicone is a specific type of caulk — the most water-resistant and durable for plumbing applications. Never use standard painter’s caulk in wet areas.
How long does silicone sealant last?
Properly applied 100% silicone lasts 10–20 years. The sealant around a tub or shower should be inspected annually and replaced at the first sign of cracks, separation, or discoloration.
Can I apply silicone over existing silicone?
No. New silicone will not bond to cured silicone. Remove all existing sealant before applying new.
Bottom Line
GE5070 100% Silicone is the professional standard and the right choice for most applications. DAP Kwik Seal Plus is easier to work with if you’re doing a tub surround and need a clean finish. Either way — clean the surface completely before applying, and don’t rush the cure time.