How do I paint over nicotine-stained walls and ceilings?

Tobacco tar is a sticky, yellow-brown, oily residue that lands on every surface in a room and is soluble in water. That combination is the worst possible case for emulsion: the water in the paint dissolves the stain, the stain travels into the wet film, and it dries at the surface as a yellow or brown patch. It gets worse with each coat, not better, because each coat re-wets what is underneath.

Safety

What you'll need

• A strong degreaser or heavy-duty cleaner, and buckets
• A solvent-based or shellac-based stain-blocking primer
• Gloves, eye protection and good ventilation
• A roller and brush you are willing to discard
• A pump sprayer, for washing large areas quickly

Step by step

1. Wash everything, not just the walls.Tar coats ceilings, walls, woodwork, the tops of doors, light fittings, radiators and the inside of window reveals. Ceilings are usually the worst affected because warm smoke rises. Wash the whole room with a strong degreaser, working bottom to top, and change the water constantly — you will be shocked at the colour.
2. Rinse properly and let it dry.Degreaser residue interferes with everything that follows. Rinse with clean water, then give the room a day or more to dry with the windows open. Painting a still-damp wall on top of a stain problem gives you two problems.
3. Deal with the smell as well as the stain.The smell is in soft furnishings, carpet underlay, curtains and inside cupboards as well as in the paint. Cleaning or removing those matters as much as the decorating, and a stain block will contain the residual odour from the walls but not from the carpet.
4. Use a solvent or shellac-based stain block, not a water-based one.This is the critical choice. A shellac-based blocker is the most reliable against nicotine and dries in minutes; a solvent-based stain-blocking primer also works. A water-based stain block is much less dependable against a water-soluble stain and is the usual reason people end up doing the job twice.
5. Block the whole affected area, not just the visible patches.In a smoker's room the contamination is everywhere, and blocking patches gives you a patchwork of different absorbency that will flash under the topcoat. Coat entire ceilings and entire walls.
6. Check before you commit to the topcoat.Let the blocker dry, then look at it in good light, especially the ceiling and the wall above where anyone sat. Any yellowing showing through gets a second coat of blocker. It is far cheaper to find this now than after two coats of emulsion.
7. Then paint normally.Two coats of your finish emulsion over a properly sealed surface. Because the blocker is non-porous and uniform, the topcoat usually covers beautifully — which is how you know the sealing worked.

Tips

• Do the ceiling first and completely, including the blocking coat, before starting the walls. It is the worst surface and the one that drips on everything else.
• Shellac-based blockers clean up in methylated spirit only and ruin brushes. Use cheap ones and accept they are consumables.
• Woodwork that has gone brown often needs washing, blocking and repainting too — the tar sits on gloss as heavily as on emulsion.

Common mistakes

• Going straight over with emulsion — Water re-dissolves nicotine tar and carries it into the wet film. It comes through the first coat, then through the second, and you have wasted both.
• Using a water-based stain block on nicotine — It is the least reliable choice against a water-soluble stain. Shellac or solvent-based is the correct product here.
• Skipping the wash and relying on the blocker alone — A blocker seals a stain; it does not bond well through a thick greasy tar film. The film has to come off first or the whole system can lift.

If it doesn't work

Questions people ask