Once the damaged material is out of a fire damaged house, you’re looking at bare framing, subfloor, and sheathing. That skeleton has to be cleaned before anything goes back over it.
Skip it and you get a house that still smells a year later. There is no fix at that point that doesn’t involve opening the walls again.
Why bare wood is the issue
Framing is unfinished and porous, so soot and smoke residue soak into the grain rather than sitting on top of it. Wiping the surface achieves almost nothing.
Put new drywall over contaminated framing and you’ve sealed the residue in. It keeps off-gassing. The odor comes back through the wall and there’s no fixing it from the outside.
How it’s done
In stages. Loose debris and char come off first, then HEPA vacuuming picks up particles instead of throwing them back into the air.
Then the surface gets abraded wherever there is char. Media blasting with soda or dry ice takes the burned layer off wood without soaking it. Dry ice has one clear advantage. It leaves nothing behind to clean up, which matters enormously in a cavity you are about to close forever.
After that, detailed cleaning of everything the blasting couldn’t reach. Then drying, because some methods introduce moisture and the structure has to be dry before anything gets sealed.
Last comes a sealing primer on framing that’s staying. Shellac based products are the usual choice. Sealing locks whatever is left into the wood so it stops releasing odor. It is the final step. Not a substitute for the cleaning that comes before it.
Telling whether it was done right
Look at the framing before drywall goes up. It should be uniformly clean rather than streaked, and char should be gone rather than painted over.
Then use your nose in a closed room with nothing running. If it still smells strongly of smoke at that point, closing the walls will not help you.
Ask what was done to the wall cavities, the attic, and the underside of the roof deck. Those get missed far more often than the visible walls. post-fire cleaning specialists in Fremont should be able to describe the method used in each area rather than talking about the house in general terms.
The forgotten parts
Attic insulation holds a huge amount of residue and usually wants replacing rather than cleaning. Ducts need dealing with before the system runs again. And the top faces of joists, which nobody ever looks at, collect soot and get missed on job after job.
Ask before rebuild
Get photos of the cleaned framing, every room. Take them yourself if nobody offers.
Ask what method was used where. Blasting in one area and hand cleaning in another is completely normal. Not knowing which happened where is not.
Ask whether the sealer went on after the cleaning or instead of it. That answer tells you most of what you need to know about the outfit you hired.
The insurance side
This is a real line item. It should show up on the estimate by itself.
If it’s missing, ask why. Adjusters sometimes leave it off because it happens behind the walls and nobody thought to photograph it.
Photos of bare framing are the fix. Take them at every stage. They cost nothing and settle arguments months later, once everyone’s memory has drifted in whatever direction suits them.
Judge it in summer
Heat brings out whatever got left behind. If a faint smell turns up on the first properly hot day, raise it while the contractor is still around and still returning calls.
Before you enter a fire damaged structure at all, official guidance on cleanup after a fire covers protective clothing, respirators, and what’s still hiding in ash and debris. Those precautions apply during the cleaning phase too, not just on the first walkthrough.
