A typical complaint

Illustrative example. Not a real job or customer.

A second-floor resident in a three-story building reports cigarette smoke in the bathroom every evening, even though nobody in the unit smokes. The unit directly below has a resident who smokes indoors, which the lease permits in that older building.

  1. Maintenance opens the vanity in the complaining unit and finds an oversized hole cut around the drain and supply lines, with no escutcheon or sealant.
  2. The same gap is found behind the toilet and around the tub spout wall.
  3. The tech checks the bath exhaust fan: it runs, which pulls air from the chase through those gaps whenever the fan is on.

Sealing the penetrations in both units and adding escutcheons cut the complaints sharply. The remaining faint odor stopped after the downstairs unit's door sweep was replaced.

Why bathrooms and kitchens are the usual entry points

Wood-frame garden and mid-rise buildings in the south metro typically run plumbing in walls that line up floor to floor. Each time a plumber or installer opens a wall or replaces a vanity, they cut holes for pipes. Those holes are often larger than the pipe, and the gap is hidden by the cabinet back or a trim ring.

An exhaust fan in a bathroom or a range hood that vents outside lowers the pressure in that room slightly. Air then comes from wherever it can, and an open chase is an easy path. The result is that the unit running its fan most often is the one that smells the neighbors.

Common gaps and how they are usually closed

Location
Under kitchen and bath sinks
Typical gap
Oversized holes around drains and supplies
Common fix
Fire-rated sealant or foam suited to the wall, plus escutcheons
Location
Behind toilets
Typical gap
Gap around the supply line and at the wall base
Common fix
Escutcheon and sealant around the line
Location
Tub and shower walls
Typical gap
Open access panel or loose trim around the valve
Common fix
Gasketed access panel, sealed valve trim
Location
Washer box
Typical gap
Open back of the recessed box
Common fix
Seal the box perimeter and any open knockouts
Location
Electrical outlets on shared walls
Typical gap
Box edges and cable entries
Common fix
Foam gaskets behind cover plates
Location
Bath fan housing
Typical gap
Gap between housing and ceiling drywall
Common fix
Seal the housing flange to the ceiling

Working through a stack

  1. Map the stack

    Identify every unit that shares the chase, above and below. Odor can skip a floor.

  2. Open and look

    Pull vanity contents, toe kicks and access panels in each unit and photograph what you find.

  3. Seal from the source side first

    Seal the smoking or cooking unit where possible, then the complaining unit, then the units in between.

  4. Retest with the fan running

    Ask the resident to run the bath fan for twenty minutes in the evening and report back for a week.

Common questions

Do we need entry to every unit in the stack?

Usually yes, with proper notice under the lease and Colorado law. Plan the work as a single project so residents get one notice and one visit.

Will sealing fix it completely?

It often reduces it a great deal. Heavy indoor smoking on the other side of a wall can still be noticed, which is why smoking policy and sealing work together.

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