Why older buildings leak smoke between units
Apartment buildings from the early twentieth century were not built with air sealing in mind. Plumbing risers, radiator pipes, electrical runs and old ventilation shafts pass through floors and walls, often with open space around them. Over decades, renovations add new holes for cable, internet and updated wiring, and few of those holes get sealed afterward. Each one is a path for air, and air carries smoke.
Pressure decides which way the air moves. In cold weather, warm air rises through a building and pushes out at the top, pulling air in lower down. A unit above a smoker often gets the worst of it in winter. Bathroom and kitchen exhaust fans can also pull air from neighboring spaces through any gap they can find, which is why the smell often seems strongest under a sink or inside a closet next to a bathroom.
None of this is the renter's fault, and much of it is outside a renter's control. Still, knowing the paths helps you describe the problem clearly, which makes it far easier for a landlord or manager to act.
Sorting out what you are dealing with
- IfThe smell comes and goes, often at the same times of day, and is sharp like a lit cigaretteIt is probably fresh smoke from another unit, a hallway or a window below. Start a log and talk to the landlord about the source.
- IfThe smell is steady and stale, present even when nobody nearby is homeIt is more likely residue left in your own unit by a past resident. That is a cleaning and treatment issue for the landlord.
- IfBoth: a constant stale background with sharper spikesYou likely have old residue plus ongoing drift. The drift needs to be addressed first or a treatment will not last.
- IfThe smell is strongest by an open windowLook outward: a balcony, fire escape, courtyard or sidewalk smoker may be the source rather than a shared wall.
Raising it with your landlord or manager
Write things down for two or three weeks
Record the date, time, rooms affected and how strong the smell was. Patterns are more persuasive than a single complaint.
Find the likely entry points
Sniff near outlets on shared walls, under sinks, around radiator pipes and at the gap under the entry door. Note the spots that are strongest.
Read your lease
Check whether it includes a no-smoking rule, a nuisance clause or a building rules attachment. Quote the relevant section in your message.
Send a short written request
Describe the pattern, the likely entry points and what you are asking for: sealing work, a reminder to residents or enforcement of an existing rule. Keep it factual and avoid naming or accusing a neighbor.
Follow up in writing
If nothing changes after a reasonable time, send a second note referring to the first. If health is involved, ask a tenant resource organization or attorney about your options under Colorado law.
Questions worth asking the landlord
- Does the building have a no-smoking policy, and does it cover balconies and hallways?
- Can maintenance seal around pipes, outlets and baseboards on the wall I share with the next unit?
- Would a door sweep or new weatherstripping on my entry door be allowed?
- Has anyone else in my stack reported the same smell?
- If the source is stopped, will the residue in my unit be cleaned or treated?
General information for Capitol Hill, not a quote or professional advice. In an emergency, call 911.