Fire and smoke damage restoration field guide, IICRC S700

What fire restoration is, and why the soot type runs the job

Fire damage restoration is the work of cleaning a building after a fire and putting back what cannot be saved. The mistake people make is treating it as one job. It is three running at once. There is the fire itself, the char and structural damage where the flame actually burned. There is the smoke and soot, which travels far past the burn and lands in rooms the fire never reached. And there is the odor, which is the last thing to solve and the hardest. On top of all of it sits the water the fire department put down, which has its own clock.

The move that makes or breaks the cleaning is identifying the soot type before you touch a surface. Dry soot from a fast, hot fire is cleaned one way. Wet soot and protein residue from a slow, smoldering or cooking fire are cleaned another. Use the wrong method and you do not just fail to clean it, you smear it into the surface and set it permanently.

So the sequence is plain: test the residue, dry the firefighting water first, remove the soot by the right method, deodorize at the source, and clean the HVAC the smoke spread through. The water damage restoration guide covers the drying side, and the mold remediation guide covers what happens when the water sits too long. This guide is the fire and smoke side, worked to ANSI/IICRC S700.

Why does the soot type dictate the cleaning method?

The soot type dictates the cleaning method because the residue is not one substance. It is whatever the fire burned, deposited on the surface, and how it burned changes the chemistry completely. Dry soot is a loose, powdery carbon that sits on top of the surface. Wet soot is a greasy, sticky film that bonds to it. Protein residue is a thin, almost invisible varnish that has to be emulsified off. Each one needs a different approach, a different chemistry, a different pH, and a different amount of mechanical action.

This is the one truth to carry off the whole guide: match the method to the residue, and test the residue first. The expensive failure is reaching for a wet cloth on dry soot. Dry soot wipes into the pores and grout and turns a powder you could have vacuumed off into a stain you cannot remove.

Run a dry chemical sponge across a hidden patch before you commit. If it lifts the soot clean, you have dry soot and you stay dry. If it smears, you have wet or protein residue and you switch to wet cleaning. Hedge the residue classification and the cleaning chemistry to IICRC S700 and the product manufacturer rather than guessing, because the wrong product can set the residue for good.

Fire restoration is three problems at once

Pull the three problems apart and you can scope the job honestly. The fire and char is the structural problem. It is where the flame burned the framing, the finishes, and the contents, and how deep the char goes decides whether a member is cleaned and sealed or cut out and replaced. That call belongs to a structural engineer, not the cleaning crew.

The smoke and soot is the contamination problem, and it is almost always bigger than the burn. Soot rides the air and the HVAC into rooms the fire never touched, so a kitchen fire can soot a whole house. The odor is the third problem, and it is the one customers judge you on, because it is the last to leave and the one that returns if you covered it instead of removing it.

The fourth problem hides behind the other three: the firefighting water. The hoses and sprinklers that put the fire out leave the building soaked, and that water starts the same mold clock as any flood. Mold can begin in roughly 24 to 48 hours, so the water has to be dried before the soot work means anything. The water damage restoration guide handles that side. Treat the fire loss as a multi-front job and you stop missing the front that bites later.

What are the types of soot?

The soot types come from how the fire burned and what it consumed, and IICRC S700 classifies smoke residue by type so the cleaning is matched to it. The four you meet on the job are dry, wet, protein, and fuel or oil soot. Identify which one you have before cleaning, because the type sets the method and the wrong method sets the stain.

Dry soot comes from a fast, hot, well-fed fire burning paper and wood. It is dry and powdery, and it brushes off. Wet soot comes from a slow, smoldering, low-heat fire short on oxygen, often burning plastics and rubber. It is greasy, sticky, and dark, and it smears. Protein residue comes from a kitchen or cooked-off fire, is nearly invisible, and carries the worst odor of the group. Fuel and oil soot, sometimes called petroleum soot, comes from a furnace puffback or an oil-burner fault and is thick and stubborn.

Treat the classification and the matching chemistry as a hedge to IICRC S700 and the product manufacturer, and confirm the type by testing the actual residue rather than the story of the fire.

Dry soot: do not wet it

Dry soot is the good news of the soot world, the type that cleans up cleanest, but only if you respect the rule. It comes off a fast, hot fire as a dry, powdery carbon that sits on the surface rather than bonding to it. Because it is loose, you clean it dry first. HEPA-vacuum the loose soot without scrubbing the surface, then go over what is left with a dry chemical sponge, a vulcanized rubber sponge that lifts soot by grabbing it as you draw it across.

The blunt rule is do not wet it and do not wipe it with a damp cloth. Dry soot is powder. Hit powder with water or a wet wipe and you turn it into a paste that drives into the pores and grout and becomes a permanent stain. The rookie move on a fire job is grabbing a sponge and a bucket and smearing dry soot across a ceiling that a vacuum would have cleared.

Work top down, dry methods first, and only move to wet cleaning on the residue the dry pass leaves behind. Confirm the approach against IICRC S700 and the product manufacturer for the surface you are cleaning, because a finish that survives a dry sponge can still be ruined by the wrong wet chemistry.

Wet soot: the greasy, stubborn one

Wet soot is the harder cousin. It comes off a slow, smoldering, low-heat fire that did not get enough oxygen to burn clean, often one fueled by plastics, rubber, and synthetics. The residue is greasy, sticky, and dark, and it bonds to the surface instead of sitting on it. Try to dry-sponge it and you just smear it, because there is nothing loose to lift.

Wet soot is a wet-clean job. You break the grease with a degreaser or an alkaline cleaning agent matched to the residue and the surface, give it the dwell time the product calls for, and back it with mechanical action, because the film does not surrender to chemistry alone. It is slower, it is messier, and it carries a heavier odor than dry soot, because the same incomplete combustion that made it sticky made it smell.

Expect to clean a surface more than once, and expect the deodorization step to do real work afterward. Match the cleaner, the pH, and the dwell time to IICRC S700 and the product manufacturer, and test on a hidden area before you commit to a finish you can wreck.

Protein residue: nearly invisible, worst odor

Protein residue is the one that fools people, because there is almost nothing to see. It comes from a kitchen or cooked-off fire, food or grease scorched on a stove, and it deposits as a thin, nearly invisible film that can leave a surface looking nearly clean. The tell is not your eyes, it is your nose. Protein residue carries the worst odor of any soot type, a deep, rancid smell that saturates a kitchen and the rooms around it.

Because you can barely see it, the trap is declaring the job done after a quick wipe while the film and the smell are still there. Protein residue has to be emulsified off with a cleaner built for it, sometimes an enzymatic agent, worked over every affected surface including the ones that look untouched. Then it needs heavy deodorization, because removing the visible film does not fully kill the odor on its own.

Hedge the cleaner choice and the deodorization plan to IICRC S700 and the product manufacturer. The honest scope on a protein fire is wider than the customer expects, because the residue went everywhere the cooking vapor did.

Why is soot damage urgent?

Soot damage is urgent because the residue is acidic and corrosive, and it does permanent damage on a clock measured in hours and days, not weeks. Soot is the product of incomplete combustion, a mix of carbon, oils, and acids, and those acids attack the surfaces they land on. Metal tarnishes and corrodes. Glass and mirrors etch and go cloudy. Grout, marble, and finishes stain. Electronics corrode from the inside as the acidic film settles on the boards.

So speed matters on a fire loss the way it matters on a water loss, just for a different reason. Every hour the soot sits, more of it becomes a replacement instead of a cleaning. Appliances, fixtures, and finishes that could have been wiped down on day one are corroded past saving by the end of the week.

That is why fire restoration is an emergency service, and why the first crew on site stabilizes and starts removing soot rather than waiting for the full scope to be written. Move fast on the acidic residue and you save the contents. Wait, and the insurer pays to replace what you could have cleaned.

Smoke travels: the job is bigger than the burn

Smoke does not stay where the fire was. It is hot, it rises, and it follows air, so it spreads through a building far past the room that burned, settling on cooler surfaces and the upper walls and ceilings in rooms the flame never reached. A contained fire in one room routinely soots an entire floor, because the smoke went looking for cold spots and found them.

It also moves through the HVAC. If the system was running when the fire started, the returns pulled smoke in and the supply pushed it to every room on the duct run, laying soot inside the ducts along the way. That is how a closed bedroom two floors up ends up with a film on the blinds.

The lesson for scoping is to follow the smoke, not the fire. Inspect for soot in the cold spots, on the high surfaces, inside closets and cabinets, and in the duct system, because the contamination is almost always wider than the burn. Scope the job to where the smoke went, or you will be back for the room you skipped.

The fire restoration process, start to finish

The work runs in an order, and the order is what keeps you from undoing your own labor. You assess and secure the building, including a board-up and dealing with the water. You remove the soot and residue by the method the soot type calls for. You clean the surfaces. You deodorize. Then you restore and seal. Jump ahead and you pay for it. Deodorize before the soot is gone and you are perfuming a problem that is still there.

Each step sets up the next. Assessment finds the soot type, the extent, and the water. Securing the building stops further loss. Residue removal gets the bulk contamination off, dry methods before wet. Surface cleaning takes the residue removal down to a clean substrate. Deodorization handles the odor once the source is gone. Restoration rebuilds and seals what could not be cleaned.

Treat this as the IICRC S700 framework rather than a rigid script, and let the soot type, the extent, and the structural findings flex the specifics. What does not flex is the logic: dry the water, get the soot off by the right method, then kill the odor at the source.

What about the firefighting water?

Dry the firefighting water first, before the soot work, because the water that put the fire out is now a water-damage and mold problem sitting underneath the fire-damage job. Hoses and sprinklers dump a large volume fast, and it soaks into the same structure you are about to clean. Left wet, it follows the flood timeline: mold can begin in roughly 24 to 48 hours under the right conditions, so the building is on a clock the moment the fire is out.

This is why a fire loss is two jobs stacked. You stop the source, extract the standing water, and build a drying environment before, or alongside, the soot removal, because cleaning soot off a wall that is soaking wet inside is wasted work that grows mold behind the finish you just cleaned.

The water damage restoration guide covers the categories, the extraction, and the drying to a dry standard, and the mold remediation guide covers what to do when the water sat too long. The order on a fire job is real: dry it first, then chase the soot, or you end up doing mold remediation on top of fire restoration.

Removing the soot: the right method, top down

Soot removal is where the soot-type call turns into hands on the wall. You get the soot off the surface, and the rule is the right method for the residue, dry before wet, working top down so the soot you knock loose falls onto surfaces you have not cleaned yet. Start with the dry tools. A HEPA vacuum lifts loose soot without throwing it back into the air, a dry chemical sponge wipes dry soot off without water, and only after the dry pass do you bring in wet cleaning for what is left.

The dry sponge is the tool people underuse. It is a vulcanized rubber sponge that grabs dry soot as you draw it across the surface, and on dry soot it does more than any wet method while leaving no smear. When you reach residue the dry methods will not lift, switch to the wet cleaner matched to the soot type and the surface, with the dwell time the product calls for.

HEPA vacuums and air scrubbers keep the soot you disturb from re-settling on clean surfaces. Match every product and method to IICRC S700 and the manufacturer, and keep testing as you go, because one fire can leave different soot types in different rooms.

How do you get rid of smoke odor?

You get rid of smoke odor by removing the source first and then treating what is left in layers, never by covering it. This is the hardest part of the job and the last, because odor is the residue you cannot see and it comes back if you cheated the steps. The order is fixed. Remove the source, meaning the soot and the charred material that is still off-gassing has to physically leave the building. Then clean the air and the surfaces. Then reach the smell where cleaning could not, with fogging or other treatments. Then seal whatever cannot be fully cleaned.

No single machine deodorizes a fire. It is layers. HEPA air scrubbers pull the smoke particles out of the air while you work. Thermal fogging re-creates the path the smoke took so the deodorant reaches the same cracks. Hydroxyl generators break down odor and are safe to run around occupants. Ozone is more aggressive and is used only in an unoccupied space. An encapsulant seals the odor in on a surface that genuinely cannot be cleaned, such as framing inside a wall.

Hedge the methods and the sequence to IICRC S700 and the product manufacturer, and treat ozone safety as a hard line, not a preference.

The rule: remove the source before you treat the air

Remove the source before you treat the air. This is the deodorization rule everything else hangs on, and it is the one shortcut that ruins fire jobs. You cannot deodorize over soot. You cannot fog a room into smelling clean while the charred joist in the cavity and the soot film on the surfaces are still there putting out odor. The fog or the ozone knocks the smell down for a few days, the customer signs off, and the odor bleeds back the first humid week.

So the source goes first, physically. The soot is removed, the charred material that cannot be cleaned is cut out and hauled off, the contents that hold odor are cleaned or discarded, and the HVAC is cleaned so it is not re-seeding the smell. Only then does air treatment do lasting work.

No perfume over a problem. If a crew leads with fogging before the soot and char are out, that is the tell the job is being shortcut, and the callback is already scheduled.

Deodorization methods and where each fits

Match the deodorization method to the situation, because each does a different job and none replaces source removal. Thermal fogging heats a deodorant into a fine fog that penetrates the same pores and cavities the hot smoke did, which is why it reaches odor that surface cleaning cannot. Hydroxyl generators produce hydroxyl radicals that break down odor compounds and are gentle enough to run in an occupied space, so they suit a building people are still living in.

Ozone is stronger and oxidizes odor fast, but it is hazardous to people, pets, and some materials, so it runs only in a sealed, unoccupied space, and the area is cleared and aired out before anyone returns. Air scrubbers with HEPA media run throughout to keep the particle load down. Sealing is the last resort, not a method of first choice. Where a surface cannot be fully cleaned, an encapsulant locks the remaining odor in.

Choose the method, the dwell, and the safety controls per IICRC S700 and the equipment manufacturer, and never run ozone in occupied space to save a day.

Clean the HVAC or it re-contaminates the rooms you cleaned

The HVAC system is the part of a fire job that gets skipped and then ruins the rest. Smoke spreads through the ductwork, especially if the system was running during the fire, so the supply ducts, the returns, the coil, and the blower carry soot and odor even in rooms the fire never reached. Clean every surface in those rooms and leave the ducts dirty, and the first time the system runs it blows soot and smoke odor right back across the clean rooms.

So the HVAC is part of the scope, not an upsell. Shut the system down early so it stops moving contamination, then clean it as its own discipline: HEPA-filtered vacuums and agitation tools under negative air to pull soot off the duct interior, with deodorization of the system afterward. The porous-versus-non-porous logic applies here too. Soot-laden insulated flex and fiberglass-lined duct often cannot be cleaned and is replaced, while bare sheet-metal duct can usually be cleaned. A dedicated duct cleaning discipline handles the detail.

Do not restart the air handler into a building until the ducts are addressed, or you re-contaminate everything you paid to clean.

Contents: pack-out, clean, save or toss

The fire hit more than the building. The contents, the furniture, the clothes, the electronics, the personal property, are sooted too, and they are their own part of the job. On a sizable loss the move is a pack-out: inventory the contents with photos, move them off-site to a facility where they can be cleaned and stored, and clear the rooms so the structure work and the deodorization have room to run.

The save-versus-toss call follows the same logic as the rest of the job. Hard, non-porous goods can usually be cleaned and deodorized. Porous items that soaked up smoke and odor, and anything the acidic soot has already corroded past saving, may not be worth restoring. Electronics that took an acidic film need specialty evaluation before they are powered on, because the corrosion keeps working inside them.

Inventory everything as it leaves, with its condition, because the contents are part of the claim and the owner needs a record of what went and why. Decisions made and documented up front are easier to defend than ones reconstructed later.

The structure and the char: not the cleaner's call

The char and structural damage is where the cleaning crew stops and a structural engineer starts. Char is the blackened, burned layer left where the flame consumed the material, and how deep it goes into a framing member decides whether the member keeps enough strength to stay or has to be cut out and replaced. That is an engineering judgment about load and lost section, not a cleaning decision, and it is not the restorer's call to make.

Where char is shallow and the member is sound, the surface may be cleaned, sometimes sanded or media-blasted, and sealed. Where the char is deep or the member is compromised, it is replaced. Get a qualified structural engineer to assess the burned structure before anyone commits to cleaning and sealing load-bearing members, and let that assessment, the manufacturer's guidance on any product used, and the insurer's scope control the decision.

The cleaning crew's job is the soot and the odor. The standing-up-the-building question belongs to the engineer, and treating it otherwise is exactly the kind of shortcut that turns a fire loss into a safety failure.

Is fire damage cleanup dangerous?

Yes, a fire scene is a hazardous place to work, and the hazards outlast the flames. The air is full of fine soot particles and the gases and VOCs that come off charred material, and breathing that is a real exposure, so respiratory protection sized to the conditions is the first decision, not the last. The char dust itself is an irritant. The structure may be weakened from the fire and the water, so the floor and the framing cannot be assumed sound.

Old buildings add a hazard the fire exposes: asbestos. Burned and disturbed old materials, insulation, floor tile, plaster, duct wrap, can release asbestos fibers, and that is a regulated material handled by a licensed abatement professional after testing, not something a restoration crew clears on its own. Electrical hazards stack on top, because the fire and the firefighting water can leave live circuits in a wet, damaged building, so the power gets confirmed dead before anyone works in it.

Match the PPE and the controls to IICRC S700, the manufacturer's ratings, and OSHA, and bring in the industrial hygienist, the abatement contractor, and the engineer when the hazard is theirs. Verify the power is dead, wear the respirator the air calls for, and never guess on asbestos.

Insurance and documentation: the documented job gets paid

Most fire losses are insurance jobs, and the documented one is the one that gets paid. The adjuster did not see the building at its worst, so your record is the proof of what you found and what you did. Photos before, during, and after, the soot type you identified in each area, the extent of the smoke spread, the scope of what was cleaned versus replaced, the moisture readings on the firefighting water, and the Xactimate estimate are what turn a sooted building into a paid claim.

Xactimate is the estimating platform most carriers price fire work in, organized by the line items the job actually used: emergency board-up, water extraction and drying, soot removal by area, contents pack-out and cleaning, HVAC cleaning, deodorization, and the rebuild. The big decision the carrier weighs is total loss versus restore, and your documentation of the soot type, the extent, and the corrosion is what supports that call.

Capture it as you go on a field tool like FieldOS so the photos, the soot-type notes, the readings, and the scope stay tied to the job, instead of a scramble through a camera roll a week later. A line item with no photo or reading behind it is a line item the adjuster cuts.

What to record

The record on a fire job is the soot type by area, the extent of the smoke and the water, the process and the products used, the deodorization method, the HVAC work, the structural and contents decisions, and the photos. Each answers a question the adjuster, the owner, or the next professional will ask later, and each is easier to capture as it happens. Tie it all to the job in a field tool like FieldOS so the package is in one place, not scattered across a notebook, a phone, and someone's memory.

Common mistakes

• Using the wrong cleaning method for the soot type and smearing it into the surface.
• Wetting or wiping dry soot instead of HEPA-vacuuming and dry-sponging it first.
• Trying to deodorize over the soot without removing the source.
• Missing the HVAC, so it blows soot and odor back across the cleaned rooms.
• Not drying the firefighting water first, so mold starts under the fire job.
• Leaving acidic soot on metal, glass, and electronics until it corrodes past saving.
• Running ozone in an occupied space to save a day.
• Ignoring asbestos in old burned material or skipping the structural assessment.

Field checklist

Standards and references

The procedural standard the trade works to is ANSI/IICRC S700, the standard for professional fire and smoke damage restoration, published in its first edition in 2025. It sets the framework for the loss assessment, the classification of smoke residue by type, the cleaning sequence, deodorization, contents handling, and the documentation behind the claim. Treat its residue classification, its cleaning methods, and its deodorization guidance as the framework, and confirm the current edition, since standards are revised over time.

Several authorities sit alongside it. The product manufacturer governs the cleaners, the chemistry, the pH, and the dwell time for the surface you are on, so use the manufacturer's instructions rather than habit. The insurer and the adjuster govern the scope and the pricing, usually through Xactimate, and own the total-loss-versus-restore decision. The structural engineer owns the burned structure and the char-depth call, and a licensed asbestos abatement professional and an industrial hygienist own the regulated-material and air-quality hazards. When the firefighting water has soaked the building, the work crosses into ANSI/IICRC S500, covered in the water damage restoration guide, and if the water sat too long, into ANSI/IICRC S520, covered in the mold remediation guide.

Three things to carry off this guide: identify the soot type, because it dictates the cleaning method and the wrong method sets the stain; dry the firefighting water first, then remove the soot and the charred source; and deodorize at the source and clean the HVAC, or the odor and the soot come back. Hedge the soot-type call, the cleaning methods, and the deodorization to IICRC S700, the manufacturer, and the insurer, and never hedge the safety.

Terms and definitions

Fire restoration carries its own vocabulary, and the same loss reads differently across a scope sheet, a product label, and an insurance estimate. These are the terms that have to mean the same thing to everyone on the job.

Fire and smoke restoration

Cleaning and rebuilding a building after a fire, covering the char, the soot, the odor, and the firefighting water

Dry soot

Powdery residue from a fast, hot fire; dry-cleaned with a HEPA vacuum and dry sponge, never wetted first

Wet soot

Greasy, sticky residue from a slow, smoldering fire; wet-cleaned with a degreaser and mechanical action

Protein residue

Nearly invisible film from a kitchen fire carrying the worst odor; emulsified off and heavily deodorized

Soot corrosivity

Soot is acidic and corrodes metal, etches glass, and stains finishes if it is left to sit

Source removal

Physically removing the soot and char before any air treatment, because you cannot deodorize over the source

Thermal fog / hydroxyl / ozone

Deodorization tools; fog penetrates like smoke, hydroxyl is occupied-safe, ozone runs unoccupied only

Encapsulant

A sealing coat applied to a surface that cannot be fully cleaned, locking the remaining odor in

HVAC re-contamination

Soot and odor left in the ductwork blowing back across cleaned rooms when the system restarts

Char

The blackened, burned layer; char depth decides whether a structural member is cleaned and sealed or replaced

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