Caulk & Sealant Inspection
Updated February 20, 2026
The caulk around your sink is the only thing stopping water from running behind the basin and into the cabinet or wall. When it cracks, peels, or develops gaps, water finds its way in silently. By the time you notice, the plywood under the countertop is swollen and mold has started growing. Checking and maintaining caulk takes 15 minutes and prevents thousands in damage.
Overview
The caulk around your sink is the only thing stopping water from running behind the basin and into the cabinet or wall. When it cracks, peels, or develops gaps, water finds its way in silently. By the time you notice, the plywood under the countertop is swollen and mold has started growing. Checking and maintaining caulk takes 15 minutes and prevents thousands in damage.
What to Know
Pro Tips
- Check caulk every 6 months -- a 2-minute visual inspection catches problems before they cause damage.
- Cut the caulk tube tip at a 45-degree angle and keep the opening small. You can always cut more, but you can't make it smaller.
- Silicone caulk doesn't stick well to old silicone. Remove every trace of old caulk before reapplying.
- A damp finger (dipped in dish soap) creates the smoothest caulk line. Silicone won't stick to soap, so it smooths without pulling.
Mistakes to Avoid
- Using latex caulk around sinks -- it breaks down with water exposure and needs replacing much sooner.
- Caulking over old, failed caulk -- the new layer won't adhere properly and will peel off.
- Skipping the cleaning step -- caulk won't bond to surfaces with soap residue, mold, or old adhesive.
- Not letting silicone cure before using the sink -- water exposure during curing prevents proper bonding.
When to Call a Pro
If you find water damage, mold, or soft wood under the sink, the caulk failure has been ongoing. Address the water damage first -- dried-out plywood can sometimes be treated, but mold may need professional remediation. If an undermount sink is separating from the countertop, the adhesive and clips need professional reattachment.
Bottom Line
Inspect caulk twice a year, recaulk when you see cracks or gaps, and always use 100% silicone. It's a $5 tube of caulk and 15 minutes of work that prevents thousands in water damage. Don't wait for the cabinet floor to get soft.