Background

Many two-story floor plans place an upstairs hall bathroom over the kitchen or family room. The tub drain, overflow and trap sit in the floor cavity between the two levels, hidden by the bathroom floor above and the drywall ceiling below.

When the gasket on a tub drain or overflow fails, water escapes only when the tub drains or when someone fills it high enough to reach the overflow. That makes the leak intermittent, and an intermittent leak is easy to dismiss for months.

What happened

Illustrative example. Not a real job or customer.

A homeowner notices a faint ring on the kitchen ceiling in the fall and assumes it is old. By spring, the ring is larger, slightly sagging, and has small dark spots at one edge. A musty smell is noticeable when the range hood is off.

  1. The homeowner stops using the hall tub and fills it partway, then drains it while someone watches the ceiling. A damp patch darkens within minutes.
  2. A plumber opens a small access hole in the ceiling and finds a failed gasket at the tub drain shoe, with water stains on the joists below it.
  3. Before enlarging the opening, the homeowner asks for containment because the kitchen is in daily use.
  4. A contractor builds a small plastic enclosure from floor to ceiling around the area, with a HEPA air filtration unit running.
  5. The stained and spotted drywall is removed, the joists are cleaned and dried, and wet insulation in the cavity is bagged out.
  6. The plumber replaces the drain and overflow gaskets, and the tub is test-filled before the ceiling is patched.

The repair stayed limited to one ceiling section. Testing the tub before closing the ceiling confirmed the fix.

Choices along the way

  • IfPaint over the ring with stain blocker?ThenDoing so would have hidden a leak that was still active. Testing first revealed the cause.
  • IfOpen the ceiling without containment?ThenFor a small plumber's access hole, many people do. Once growth was likely, containment protected an occupied kitchen.
  • IfReplace the whole kitchen ceiling?ThenNot needed. Removal followed the wet and stained area plus a margin, guided by moisture readings.

Common questions

Could the bathroom floor have been opened instead of the ceiling?

Sometimes, but tile and a tub are far more expensive to remove than a patch of ceiling drywall. Opening from below is the usual choice for drain work under a tub.

General information for Highlands Ranch, not a quote or professional advice. In an emergency, call 911.