Cleaning soot off original fir trim and built-ins in a Seattle Craftsman

Walk through an old house in Wallingford, Ravenna, Phinney Ridge, Beacon Hill or Mount Baker and you will often find the original fir: door and window casings, box beams, plate rails, colonnades, window seats and dining room buffets, much of it still under an old clear finish. A small fire, a kitchen flare-up or a fireplace that backed up can leave a film of soot on all of it.

Old woodwork is easier to damage than to clean. This guide covers light, dry soot after a small fire. If the fire was bigger than that, start with the first 72 hours after a house fire.

Why old fir needs different handling

Much of that trim wears shellac, old varnish or both, often under later coats, and you usually cannot tell which by looking. Shellac softens under alcohol and can cloud when water sits on it. Old varnish can haze. Degreasers and other strong alkaline cleaners, including TSP, can dull or strip either one. Those are products for a crew that knows how to rebuild a finish afterward, not for a homeowner with a bucket.

The order matters too. Soot sits on top of a sound finish, but in open grain and worn spots, water and hard rubbing can push it in. Dry methods first take off most of it without that risk.

Read the residue first

Photograph every room before you touch anything. If a claim is possible, tell your insurer and ask whether they need anything before you start, but do not let the question take days, because soot keeps working on finishes.

Then pull a clean white cotton cloth lightly across the top of a door casing or plate rail, out of sight:

• Dry grey or black dust that lifts off: dry smoke, from a fast, hot fire. This guide applies.
• A greasy, sticky or smeary film with a sharp smell: wet smoke from plastics or foam, or protein residue from burned food. Stop. A dry sponge will smear it, and it needs a different cleaner.
• A bubbled, wrinkled or crazed finish, or darkened wood: heat damage. That is a refinishing job, not a cleaning job.

Safety in an older house

• Wear an N95 or P100 respirator, nitrile gloves and eye protection, and keep the furnace fan off while you work so soot does not travel through the ducts.
• Treat old paint as lead until tested. Clear-finished fir in the front rooms is often paired with painted trim in kitchens, baths and bedrooms. In any house built before 1978, gentle dry cleaning and damp wiping are fine. Scraping, sanding or scrubbing hard enough to remove paint is not.
• Leave textured ceilings alone. Older popcorn ceilings may contain asbestos. A stained one goes to a professional.
• Stay away from anything electrical that is scorched, warm or discolored, and have an electrician check it first. Some older Seattle houses still have knob-and-tube wiring.

Step by step: cleaning the trim

1. Set up. Cover the floors with drop cloths. Empty the built-ins and box what came out to clean separately.
2. Vacuum, top down. Use a HEPA vacuum with a soft brush, starting with beams and plate rails and finishing at the baseboards. A household vacuum without a HEPA filter blows the finest particles back into the room.
3. Dry-sponge with the grain. Use a dry chemical soot sponge in straight, overlapping strokes with light pressure. Heavy pressure can push soot into the pores. Turn the sponge as it darkens, cut it into smaller pieces for narrow trim, and throw it out when it is black. Never wet one.
4. Clear the profiles. Work beads, grooves and corners with a clean, soft paintbrush, holding the vacuum nozzle right next to it.
5. Check with a flashlight. Hold the light low across the wood. If the surface looks clean, you may be done, and that is the best outcome for an old finish.
6. Test before any damp cleaning. Pick a hidden spot, such as the inside of a closet casing. Dilute a wood cleaner or oil soap as the label says, dampen a cotton rag and wring it nearly dry. Wipe, let it dry and look. If the finish clouds or softens, or color comes off on the rag, stop.
7. Damp-clean in short sections. Work with the grain, top down, and dry each section at once with a second cloth. Change rags often. Never leave water on joints, at the bottom of casings or on top of built-ins.
8. Let it dry overnight, then recheck in low-angle light and sponge any spots you missed.
9. Hold off on polish and wax. Wait until the wood is clean and the smell has cleared, and then decide whether it needs anything at all.

Bag used sponges and rags and put them in the garbage.

Built-ins, glass and hardware

Clean the inside, the back and the top of every built-in; smoke reaches those as easily as the front. Wipe art glass and leaded panes gently with a barely damp soft cloth, without pressing on old lead strips. Soot can corrode metal, so wipe old door and cabinet hardware early. Leave brass polish until the wood around it is done, because polish residue marks wood.

What it costs

These are typical Puget Sound ranges, not quotes; prices vary with the house, the finish and how far the smoke went.

• Dry chemical sponges: a few dollars each, and a room of trim can take several.
• HEPA vacuum: usually $100 to $250 to buy.
• Respirators, gloves, cotton rags, brushes and wood cleaner: usually $40 to $100.
• Lab test of a paint chip for lead: usually $10 to $50 per sample.
• Professional soot cleaning: commonly several hundred dollars for light residue in a room or two, to the low thousands when it reached several rooms.
• Refinishing heat-damaged trim or built-ins: priced after a finisher sees it, and often in the thousands for a room.

A sudden accidental fire is usually covered under a homeowners policy, subject to your deductible, and a small cleanup may come in under it. Ask your agent before you decide. When a restoration contractor handles the work on a claim, it is $0 upfront on covered claims - insurer billed directly - deductible applies.

When to call a professional

Stop and call if:

• The residue is greasy or smears, or the white cloth test showed anything but dry dust.
• The finish is bubbled, soft or sticky, the test spot clouded, or the wood is charred.
• Soot reached more than a room or two, or the ceilings, closets or ducts. Smoke and soot cleanup explains how residue is matched to a method.
• The smell is still strong after two or three days of airing out. Smoke odor removal covers the options; ask how the crew would treat clear-finished wood, since a standard odor-blocking primer would hide the grain.
• Firefighting water reached the trim and it is swelling or lifting. See water damage after a fire.
• Paint is chipping, or young children or someone pregnant lives in the house.
• The built-ins hold more than you can clean. Contents cleaning and pack-out handles that part.

When you call, say that the trim is original and that you want it cleaned rather than painted. Dispatch covers every Seattle neighborhood any hour at (425) 842-3483.