Fire and smoke damage claims are among the most complex — and most under-paid — in the restoration industry. The initial adjuster estimate typically captures the visible structural loss. What it misses is everything that's harder to see: smoke infiltration into HVAC systems, protein smoke residue on painted ceilings, chemical residues on soft contents, and concealed structural damage discovered during demolition. These omissions represent thousands of dollars per job that belong in a well-written supplement letter.
The IICRC S540 (Standard for Professional Trauma and Crime Scene Remediation — which also governs smoke and fire residue cleaning) along with the more widely cited IICRC S520 framework for contamination provide the authoritative basis for justifying your fire restoration scope. Here's how to structure a supplement letter that covers every disputed line item.
Smoke Type Identification: The Foundation of Your Cleaning Justification
Not all smoke is the same. The type of smoke produced by a fire — determined by what burned, the temperature of combustion, and the oxygen supply — dictates the cleaning protocol required. An adjuster's generic "smoke cleaning" allowance is almost never adequate when you identify the actual smoke types present and match them to the protocols they require.
Protein Smoke
Produced by low-temperature combustion of animal proteins — kitchen fires involving meat, grease, and food materials. Protein smoke is nearly invisible, doesn't leave heavy soot deposits, but penetrates deeply into porous materials and leaves a persistent, oily residue with a strong odor. Protein residue is extremely difficult to remove from painted surfaces; it often requires complete repainting after cleaning rather than simple wiping. Protein smoke is the most underestimated smoke type in adjuster estimates.
Wet Smoke
Produced by slow-burning, low-heat fires with smoldering combustion — common with rubber, plastic, and wet materials. Wet smoke leaves a thick, sticky, smeary residue with a strong pungent odor. It is the most difficult smoke type to clean; improper cleaning (wiping without the correct chemical agents) can spread the residue and permanently set staining. Wet smoke residue on porous surfaces often necessitates replacement rather than restoration.
Dry Smoke
Produced by fast-burning, high-temperature fires with ample oxygen supply. Dry smoke is powdery, less adhesive, and typically easier to clean than wet or protein smoke. However, the higher fire temperatures that produce dry smoke often mean greater structural damage and more extensive charring of structural components — supplementable items that may not appear in the initial estimate.
Fuel Oil / Chemical Smoke
Produced by furnace puffbacks, chemical fires, or petroleum product combustion. Fuel oil smoke leaves an extremely penetrating, oily black residue that requires specialized cleaning agents and processes. In some cases, affected porous materials must be replaced. Fuel oil claims also raise the question of VOC (volatile organic compound) contamination, which may require air quality testing.
💡 Document smoke type in your letter: "Initial assessment identified [wet/protein/dry/fuel oil] smoke residue in [areas]. This determination is based on visual characteristics of the residue, odor profile, and material involvement. Per IICRC S540 guidance, [wet/protein] smoke residue requires [specific protocol] — a significantly more labor-intensive and material-intensive process than the generic smoke cleaning allowance in the adjuster's estimate accounts for."
HVAC System Contamination: The Supplement Item Adjusters Always Miss
Smoke travels through HVAC systems during a fire. A fire in one area of a building can contaminate ductwork, air handlers, evaporator coils, and supply registers throughout the entire structure — including areas with no visible fire or smoke damage. Adjusters who never worked a fire don't think about HVAC. You do.
HVAC contamination must be addressed for two reasons: incomplete cleaning leaves an ongoing odor source that will cause claim reopening complaints, and contaminated HVAC systems can redistribute residue throughout the structure after restoration is complete. Neither outcome serves anyone. Document the HVAC scope in your supplement with specificity:
- Duct inspection: Scope or visual inspection of all accessible ductwork with photo documentation of residue inside ducts
- Duct cleaning: NADCA (National Air Duct Cleaners Association) standard cleaning protocol, including source removal, contact vacuuming, and blow-and-collect method for debris
- Evaporator coil cleaning: Coil cleaning with appropriate EPA-registered chemical agents — coils collect smoke particulate and become a reservoir for odor if not cleaned
- Air handler interior cleaning: Blower compartment, drain pan, and housing interior
- Supply register cleaning or replacement: Heavily contaminated registers may require replacement rather than cleaning
- Odor treatment: Thermal fogging or hydroxyl generation inside ductwork after cleaning if odor is present
Structural Line Items: What the Initial Estimate Doesn't See
The initial adjuster estimate for a fire loss is based on what is visible during the initial inspection — usually before demolition begins. Structural damage concealed by finished surfaces, fire suppression water damage, and charring that extends beyond the visible fire boundary are all discovered during demolition and documented in a supplement.
Charring Depth and Structural Member Involvement
Document charred structural members (joists, rafters, wall studs) with measurements of char depth and affected length. Reference the applicable code — most jurisdictions require replacement of structural members with char depth exceeding ¼ inch in any dimension, or where the remaining section is insufficient to carry design loads. Structural engineering assessment may be required and is a legitimate supplementable cost.
Fire Suppression Water Damage
Sprinkler activation and fire department hose operations introduce Category 3 water into the structure (water mixed with fire suppressant chemicals, fire residue, and exterior contamination). This activates IICRC S500 Category 3 protocols for all materials in contact with suppression water — a fact that many adjusters treat as water damage subject to a separate water mitigation claim. Address it in your supplement with a clear explanation of why the suppression water category requires the same material removal and drying protocols as any other Category 3 loss.
Thermal Damage Beyond the Fire Origin Area
High heat travels through structural assemblies. Damage to framing, sheathing, and roof decking can extend well beyond the visible burn area. Photo-document the extent of heat discoloration, deformation of metal fasteners and connectors, and any areas where adhesive connections have failed. Each of these is a supplementable item if it wasn't in the original estimate.
Asbestos and Lead Discovery: The Required Stop-Work Protocol
Pre-1980 structures — and many structures built through the 1990s — may contain asbestos-containing materials (ACM) or lead-based paint in the areas affected by fire and smoke damage. During demolition, discovery of suspect materials triggers a mandatory stop-work protocol that belongs in your supplement letter.
When suspect ACM is discovered during fire damage demolition, work in the affected area must stop until:
- Suspect materials are sampled by a licensed asbestos inspector or industrial hygienist
- Laboratory analysis (PLM — polarized light microscopy) confirms or rules out asbestos content
- If positive: a licensed asbestos abatement contractor is retained and abatement is completed per applicable state regulations (OSHA 29 CFR 1926.1101) before restoration work resumes
The costs associated with testing, work stoppage, and abatement are all supplementable — and the stop-work is not optional. An adjuster who disputes these costs is disputing EPA and OSHA regulatory requirements. Include the sampling lab report, the abatement contractor's scope, and any work stoppage time in your supplement. Reference the applicable state asbestos program regulations by name if known.
✅ Asbestos discovery language: "During demolition of [area], suspect asbestos-containing material was identified in [drywall joint compound / floor tile / pipe insulation]. Per OSHA 29 CFR 1926.1101 and [State] Department of Environmental Protection regulations, all work in the affected area was suspended pending bulk sampling and laboratory analysis. Sampling was performed by [licensed inspector] on [date]; laboratory results (attached) confirmed ACM presence at [X]% chrysotile content. Licensed abatement contractor [name] performed abatement per [State] regulations. All associated costs are required by law and are supplemented below."
Odor Treatment: Documenting Why Basic Deodorization Isn't Enough
Adjusters frequently allow a single line item for "deodorization" that covers thermal fogging or ozone treatment. On serious smoke losses — particularly protein smoke and wet smoke jobs — this is wholly inadequate. Your supplement needs to explain why.
Effective odor treatment for smoke losses requires a multi-method approach: source removal first (cleaning or replacing contaminated materials), followed by thermal fogging to penetrate porous surfaces, followed by hydroxyl generation for ongoing treatment of residual odor in the structure. Each method addresses a different aspect of smoke odor and they are not interchangeable. Reference the IICRC S520/S540 odor control hierarchy in your letter and document each treatment method, duration, and area treated separately.
Fire and smoke supplement letters with the right citations, every time
InsurScribe generates fire damage supplement letters with accurate smoke type identification, HVAC contamination scope, structural item documentation, and asbestos discovery language — automatically. Try InsurScribe free for 3 days and recover the full scope of every fire loss.
Try InsurScribe Free for 3 Days →