A fire leaves three separate problems behind, and only one of them is the burned material. There is also the soot and smoke residue that travelled everywhere the air went, and the water the fire service used to put it out — which is a full water damage loss on top of the fire.
First: stabilise the building
Before any cleaning begins the structure has to be secured. That means board-up of openings, temporary weather protection where the roof or walls are compromised, and confirming with the appropriate authorities that the building is safe to enter. In a Minnesota winter there is an added urgency — an open structure with no heat will freeze remaining plumbing and turn one loss into two.
Soot is not one thing
What burned determines how the residue behaves and how it has to be cleaned. Dry, high-oxygen fires leave a powdery soot that can often be removed dry, and using water on it first will smear it into the surface permanently. Smouldering, low-oxygen fires leave a dense, sticky residue that requires solvent cleaning. Protein fires — typically kitchen fires — leave almost no visible residue but an intense odour and a thin varnish-like film on everything.
Getting this wrong at the start makes the damage permanent, which is why surfaces are tested before a cleaning method is chosen rather than after.
Where the residue actually went
Smoke follows air movement, which means it goes into the HVAC system and gets distributed through the building, into closets and drawers, behind wall plates, into the attic through ceiling penetrations, and onto the cold surfaces of exterior walls. Cleaning only the visibly affected room leaves the source of a recurring smell everywhere else. Ductwork is inspected and addressed as part of the work.
Corrosion runs on a clock
Soot residues are acidic. Left on metal, they etch — appliance finishes, plumbing and electrical fixtures, HVAC components, electronics. The window for preventing permanent damage is measured in days, not weeks, which is why stabilisation and initial cleaning are not things to leave until a claim is settled.
Contents and rebuild
Contents are triaged into what can be cleaned on site, what needs off-site treatment, and what is not salvageable — with the last category documented before disposal. Once cleaning is complete and odour work is done, remaining reconstruction is scoped so the building goes back together properly.