How do I get cigarette smoke smell out of a room?

Smoke leaves a sticky tar film on every surface including the ceiling, so this is a washing job rather than a deodorising one — and paint alone will not seal it.

Difficulty: intermediate
Time: 4 hr
Read: 4 min
Safety: caution

Short answer

Ventilate hard, then wash every hard surface including the ceiling with sugar soap, launder or replace all soft furnishings, and prime with a stain-blocking primer before repainting. Air fresheners and ozone treatments do nothing about the film that is producing the smell.

Tobacco smoke deposits a yellow-brown resin on everything in the room, and that film keeps releasing odour compounds for years — known as thirdhand smoke. It is why a room can smell strongly of smoke long after anyone stopped smoking in it, and why cleaning the obvious surfaces makes surprisingly little difference. The ceiling, which nobody washes, often holds the heaviest deposit.

Safety

Sugar soap and strong degreasers are alkaline and irritate skin and eyes — wear gloves and ventilate. Never mix a cleaner with bleach or with any other product while working through a room. If you are stripping nicotine film from surfaces in a property built before 2000, do not sand or scrape anything that might be an artex or textured coating, which can contain asbestos.

What you'll need

Sugar soap or a strong degreaser
Buckets, cloths and a sponge mop for the ceiling
Gloves and eye protection
Stain-blocking primer (optional)

The order to clean a room

Step by step

Ventilate before and throughout.Windows open on opposite sides, and a fan pushing air out rather than in. This alone shifts the airborne fraction, which is the smallest part of the problem but the quickest win.
Take out everything soft.Curtains, cushions, rugs, bedding, lampshades. They hold the most odour by mass and they cannot be cleaned in place.
Wash the ceiling first.It carries the heaviest tar film and almost nobody thinks of it. Sugar soap on a sponge mop, working in sections, with the floor covered.
Work down the walls in overlapping sections.Two buckets, one wash and one rinse. You will see the water go orange-brown almost immediately, which tells you what was on the surface.
Do the surfaces nobody washes.Tops of doors and frames, light fittings, switch plates, radiator backs, skirting tops, window reveals, inside cupboards and the inside of the extractor.
Launder soft furnishings, or replace them.Curtains at the hottest temperature the label allows, cushion covers likewise. Foam inserts that smell after washing usually need replacing — foam holds odour indefinitely.
Deep clean carpet, or accept it needs replacing.A hot water extraction machine with an enzyme solution, done twice. Underlay holds smoke too, and a heavily smoked-in carpet usually cannot be recovered.
Prime before you paint.Emulsion over nicotine yellows within weeks as the tar bleeds through, and it does not seal the smell. A shellac or purpose-made stain-blocking primer is what stops both.
Deal with soft goods you cannot wash.Books, papers and upholstery respond to weeks of ventilation, or to sealing in a box with bicarbonate of soda or activated charcoal for a fortnight.
Keep ventilating for weeks afterwards.Residual odour comes out of joinery and plaster slowly. A window ajar daily for a month does more than any single treatment.

Tips

Wash a small test patch of wall first. The colour of the rinse water tells you immediately how heavy the deposit is and whether this is a wash or a repaint job.
Change the wash water frequently — once it is brown you are redistributing tar rather than removing it.
Activated charcoal in open trays absorbs residual odour better than bicarbonate, and lasts longer. Both need weeks, not hours.

Common mistakes

Painting over nicotine without a blocking primer — Tar is soluble in the water in emulsion, so it bleeds through and yellows the new paint within weeks. It also continues to release odour through the paint film.
Trying to solve it with air fresheners or ozone — Neither removes the film that is producing the smell, so the smell returns as soon as the treatment stops. Ozone generators are also harmful to breathe and can damage rubber and fabric.

If it doesn't work

Smell returns after a few weeks

Cause: A soft item or the carpet underlay is still holding it — Fix: Work through remaining soft goods one at a time, isolating each in a sealed bag for a day to test whether it is a source.

Yellow patches showing through new paint

Cause: Painted without a stain-blocking primer — Fix: Wash the surface, apply a shellac-based blocking primer, then repaint. Emulsion alone will keep yellowing.

Walls washed but the room still smells

Cause: The ceiling was not washed — Fix: Wash the ceiling. It carries the heaviest deposit and it is the surface most often skipped.

Smell strongest near the heating

Cause: Tar on radiators and inside vents releasing when warm — Fix: Clean behind and between radiator fins and inside any ventilation grilles and extractor housings.

Questions people ask

How long does it take for the smell to go completely?

With a full wash, new soft furnishings and a blocking primer, a few weeks. Without the wash, indefinitely — ventilation alone does not remove a surface film.

Is it worth it in a rented flat?

Washing surfaces and replacing soft furnishings is usually enough and is worth doing. Repainting is the landlord's decision — raise the yellowing before you move in rather than after.

Does vinegar in bowls work?

It absorbs a little airborne odour and does nothing about the film on the walls. It is a supplement to cleaning, never a substitute.