What is different about plaster
Plaster itself is hard and dense, and after a century it is usually covered by many coats of paint. In most rooms the nicotine film sits on the top coat of paint, much as it would on drywall. The trouble spots are the exceptions: hairline cracks and crazing that let residue into the plaster, gaps along picture rail and crown molding, and any spot where the paint has worn through.
Wallpaper is the bigger hazard. Paper and its paste are porous and soak up smoke, and residue can sit between the paper and the wall. If smoke-stained wallpaper is staying, expect the smell to stay with it. If it is coming off, plan the removal before any odor treatment, not after.
Some early ceilings were finished with calcimine, a chalky water-based paint. Washing it can turn it to paste, and new paint often peels off it. If a ceiling chalks onto your fingers or dissolves when damp, ask a painter how they plan to deal with it before anyone washes it.
A practical sequence for plaster rooms
Map the surfaces
Note which walls are painted plaster, which are papered, and whether ceilings chalk. Mark cracks and loose areas with painter's tape.
Strip wallpaper first if it is going
Removing paper after cleaning undoes the cleaning; removing it first exposes the residue underneath so it can be handled in one pass.
Clean painted plaster top to bottom
Use a cleaner suited to smoke residue, a light touch around cracks, and frequent rinse-water changes so the film is lifted, not smeared.
Repair cracks after cleaning
Patch and tape cracks once the surface is clean so new compound bonds to sound plaster.
Seal with an odor-blocking primer
A shellac-based or other stain-blocking primer over the whole surface traps whatever remains in the old paint layers.
Paint
Finish coats go on only after the primed room passes a closed-up smell test.
Keep the plaster or replace it?
Replacement is rarely necessary for odor alone.
Usually keep and seal
- Sound plaster with intact paint
- Residue that wipes off with cleaning
- Cracks that are cosmetic
- Rooms with original details worth preserving
Consider partial replacement
- Plaster that is crumbling or detached from lath
- Areas soaked by leaks as well as smoke
- Walls opening up anyway for electrical or plumbing work
- Spots where odor persists after cleaning and priming
Common questions
Does plaster absorb smoke more than drywall?
Painted plaster in good condition usually holds no more odor than painted drywall, because the residue sits on the paint. Cracks, worn spots and wallpaper are where older walls hold more.
Will an odor-blocking primer stick to old oil-based paint?
Many shellac-based primers bond to old oil paint, but adhesion depends on cleaning and the specific product. Ask your painter to do a small adhesion test before committing a whole room.
General information for Cherry Creek, not a quote or professional advice. In an emergency, call 911.