Check bathroom caulking

Inspect bathroom caulking to catch failures before water causes damage.

Why it matters#

Damaged caulking lets water seep behind walls and under flooring, causing mold, rot, and expensive structural damage. Regular inspection catches problems early.

What you'll need#

Tools#

• Flashlight
• Utility knife or caulk removal tool (if replacing)
• Caulk gun (if replacing)

Materials#

• Silicone bathroom caulk (if replacing)
• Painter's tape (for clean lines)
• Rubbing alcohol (for surface prep)

Steps#

1. Inspect the tub/shower perimeter#

Look at the caulk line where the tub or shower meets the wall. Look for gaps, cracks, peeling, or discoloration.

2. Check around the shower door or curtain area#

Inspect caulk where shower doors meet the tub or tile. Missing or damaged caulk here lets water escape.

3. Examine sink and countertop joints#

Check where the sink meets the countertop, and where the countertop meets the wall backsplash.

4. Inspect around the toilet base#

Look at the caulk around the base of the toilet where it meets the floor. (Note: some plumbers prefer no caulk here to reveal leaks.)

5. Check for mold or mildew#

Dark spots in caulk indicate mold growth. Surface mold can be cleaned, but mold that has penetrated the caulk means replacement.

6. Test adhesion#

Gently press on the caulk with your finger. It should feel firmly attached. If it peels away or feels soft and spongy, it needs replacement.

7. Look for water damage signs#

Check the walls and floor near caulked areas for soft spots, discoloration, or peeling paint that could indicate water getting behind the caulk.

8. Note areas needing attention#

Make a list of spots that need re-caulking so you can address them all at once.

Pro tips#

• Check caulking every 6 months and replace as needed—typically every 3-5 years in heavy-use bathrooms
• Use 100% silicone caulk for wet areas—it's more flexible and water-resistant than acrylic
• Before re-caulking, remove all old caulk completely—new caulk won't adhere well over old
• Apply caulk when the tub is filled with water—this accounts for the tub flexing under weight

Warnings#

• Damaged caulking lets water seep into walls, causing mold, rot, and expensive structural damage
• Don't caulk over mold—it will continue growing underneath
• Ensure good ventilation when using caulk, and follow product safety instructions

When to call a pro#

Re-caulking is a straightforward DIY task. However, if you find water damage behind walls, soft/spongy subfloor, or significant mold growth, call a contractor to assess damage before simply re-caulking.