Cracked Caulk by Your Tub? Why It Matters
Cracked tub caulk lets water behind the tub and into the subfloor. Learn the warning signs and how The Great House fixes it in Northern Virginia.
BATHROOM REMODELING
12/7/20263 min read
ASK MASON · BATHROOM
Cracked Caulk by Your Tub? Why It Can Rot the Floor Underneath
Mason shows why tub caulk matters, the signs water is getting in, and how we fix it right.
A small crack in the caulk around your tub can rot the floor underneath it.
Watch Mason’s video, then read why that seam matters, the signs to watch for, and how we fix it.
01
What Mason Checks
The Seam Between Your Tub and the Wall
THE GAP
Where the tub meets the wall, there’s a seam.
THE CAULK
A bead of caulk seals that seam.
EVERY SHOWER
Water runs down the wall and hits it.
Where your tub meets the wall, there’s a gap. A bead of caulk seals that seam.
Every shower, water runs down the wall and hits that seam. Good caulk keeps every drop inside the tub.
Caulk gets old. It dries out, cracks and pulls away from the tile.
Mason’s diagram: fresh caulk vs. old cracked caulk at the tub
A thin line of caulk is all that stands between your shower and your subfloor.
02
Warning Signs
Signs Your Tub Seal Is Failing
CRACKED CAULK
Caulk that’s cracked, peeling or missing.
BLACK MOLD
Corners with mold that won’t wipe off.
SOFT FLOOR
A soft spot on the floor next to the tub.
Water sneaks through the crack, runs behind the tub and soaks the bottom of the wall.
Slowly, the wall board turns soft, the subfloor under the tub starts to rot, and mold grows where you can’t see it.
Check this today
Run a fingernail along the caulk line. If it lifts, cracks or has gaps, it needs to be redone. Press on the floor beside the tub for soft spots.
03
How We Fix It
A Quick Recaulk Now, or a New Floor Later
We cut out all the old caulk and check the wall behind it. If the wall or floor is soft, we open it up, dry it and replace the rotted wood. Then we clean the seam and apply fresh, mold-resistant caulk.
Caught early vs. caught late
Caught early, it’s a quick recaulk. Caught late, it’s a new tub surround and a new floor.
In Northern Virginia
Many Northern Virginia homes are 40 to 60 years old. In Arlington, about 45% of homes were built before 1970 (U.S. Census, 2019–2023). After decades of showers, the original tub seams in many of these homes have been recaulked over and over, and rarely checked behind. We dealt with this when we replaced an old tub on our Calamo St bathroom remodel in Springfield.
Planning a bigger project?
Remodeling your bathroom? We check the wall and subfloor behind every tub we replace. See prices and real projects on our bathroom remodeling page.
The fix: the wall opened and dried before new tile and caulk
ASK MASON · BATHROOM
Want to know another problem?
SPOTTED ONE OF THESE SIGNS?
We’ll check it before it turns into a big repair
Free in-home visit from a Class A licensed team. We check the problem and the rest of your bathroom, then give you a clear written plan.
ABOUT THE AUTHOR
The Great House team
Written by the team at The Great House LLC, a Class A licensed builder and remodeler in McLean, VA (License #2705197237). We have renovated 30+ Northern Virginia homes since 2022.
PLANNING A PROJECT?
Our bathroom remodeling service
See prices, real photos and how we work: our bathroom remodeling page. Real projects: our project gallery.
Serving McLean, Vienna, Great Falls, Fairfax, all of Northern Virginia.