Nobody goes back in until the fire department or building department says the structure is safe to enter, and the electricity and gas stay off until they have been inspected. Openings are boarded up and the roof is tarped if it was breached. Water from firefighting is pumped out and the structure dried, because wet framing and drywall left for days become a mold problem on top of the fire.
Smoke travels through the whole home on heat and air currents and settles in rooms far from the fire, inside closets, ductwork and behind cabinets. The residue differs by what burned: a fast, hot fire leaves a dry, powdery soot, a smoldering fire leaves a wet, sticky residue that smears, and a kitchen fire leaves a nearly invisible protein film with a strong odor. Do not wipe walls or furniture yourself before the crew arrives. Each residue needs a different cleaning method, and the wrong one makes the stain permanent.
A home that did not burn can still be a fire job. Wildfire smoke and ash settle into attics, ducts, insulation and soft furnishings, and ash from burned structures can carry asbestos, heavy metals and other toxic residue. It is cleaned with wet methods, HEPA vacuums and respirators, never by dry sweeping or leaf blowers. Ask for a written scope that says what will be tested, what will be cleaned and how.
Contents that can be restored are often packed out, cleaned off site and stored until the home is ready. Odor is treated last, after the sources of the smell are gone, with air treatments such as fogging or ozone and by sealing surfaces that still hold odor. Ozone is run only in an empty house, with people, pets and plants out until it has aired, because it is harmful to breathe. Odor treatment on a home that has not been cleaned first does not last.
For insurance, the key document is the company's written scope: a list of what was damaged, what will be cleaned and what will be replaced. Keep the fire department report, photos from before anything was moved, and receipts for emergency costs. Standard homeowner policies include coverage for additional living expenses while the home cannot be lived in; ask your insurer what yours covers and keep every receipt. The California Department of Insurance takes complaints if a claim stalls.
Fire restoration needs a Contractors State License Board license for work worth $1,000 or more, or any work that needs a building permit. Rebuilding after a fire is general building work, and a company that only cleans may bring in a licensed builder for that part. Check the record at cslb.ca.gov, and ask which IICRC certifications the technicians hold.