Paint Type

Intumescent Paint

Intumescent paint is a passive fire-protection coating that expands under high heat to form an insulating char layer over an approved substrate.

Intumescent paint surface compatibility

Intumescent paint can protect approved steel, wood, drywall, or concrete, but primer, film thickness, topcoat, and installation must match the tested fire rating.

Surface Compatibility Preparation Primer or ground Finish Guide
Metal Excellent for structural steel when part of an approved intumescent system Prepare steel to the coating manufacturer's specified cleanliness and profile, removing rust, scale, oil, grease, and incompatible coating. Use only the primer approved for the tested intumescent system. Apply the required dry-film thickness and compatible topcoat, if specified, to achieve the designed fire-protection performance.
Wood Good when the exact intumescent system is tested and approved for the wood assembly Use sound, dry, clean wood and follow the system's requirements for existing finishes, moisture, sanding, and repairs. Use only the primer or base coat specified for the tested wood system. Required coating thickness and any protective topcoat must follow the approved fire-protection specification.
Drywall Good when included in a tested intumescent wall or ceiling system Repair damaged board or joints, remove dust and contamination, and make sure the assembly matches the specified substrate condition. Use only the primer or sealer approved by the intumescent coating system. Do not infer a wall fire rating from the coating alone; the complete tested assembly and specified film thickness control performance.
Concrete Good when the intumescent system is approved for the concrete assembly Use cured, sound, dry concrete and remove dust, laitance, contamination, loose material, and incompatible coatings as specified. Use the compatible primer or sealer required by the tested coating system. Apply and inspect the specified film thickness and any required topcoat as part of the complete passive-fire-protection system.

Sources: Sherwin-Williams: What Is an Intumescent Coating?, PPG Steelguard 119 W, and Jotun SteelMaster 600WF.

Painters who used intumescent paint

Browse PaintZeal painter profiles featuring artists who used intumescent coatings, with examples of fire-protection materials repurposed in experimental artwork.

Martand Khosla

Martand Khosla is an Indian artist and architect whose work examines construction, demolition, memory, and urban change through architectural materials and processes, including laser etching into intumescent paint.

Intumescent paint articles

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