As winter 2025/26 approaches and homeowners ready their fireplaces for cozy evenings, new fire safety questions emerge. Many builders and remodelers are finishing basements or sealing gaps in walls with spray polyurethane foam (SPF) for extra insulation, even around chimneys and fireplace surrounds.
Exposed SPF can ignite if it absorbs enough heat, so before you start a fire this season, it’s critical to protect your SPF with a code-approved barrier. A nearby gas, wood-burning, or electric fireplace can heat adjacent foam well above its safe temperature, creating an ignition risk just when families are gathering to celebrate. Thankfully, IFTI’s DC315 intumescent coating provides a proven solution.
Spray foam is combustible and will burn if exposed to a high enough temperature. Fire officials and code bodies caution that foam insulation should always be considered flammable unless properly protected. In practice, this means that foam touching a warm chimney chase or the wall behind a fireplace must be concealed. Even if the fireplace is gas-powered (without flames), the nearby wallboard or framing can heat up past 240°F – the temperature above which many foams begin to decompose or burn.
Leaving SPF exposed in these areas is not only unsafe but typically violates building codes. Contractors should remember that fire codes generally require a minimum clearance between fireplaces (and their vents or flues) and any combustible materials, including spray foam and wood framing. In short, unprotected foam next to an active hearth is a hidden holiday hazard.
Building codes are explicit about fire barriers for foam insulation. Both the International Residential Code (IRC) and International Building Code (IBC) mandate a 15-minute thermal barrier between any foam plastic insulation and the occupied interior of a building. This 15-minute rating means the covering must slow heat enough that the foam underneath doesn’t exceed 250°F in 15 minutes of fire exposure. In conventional construction, ½-inch drywall often serves this role. Alternatively, the code allows specially tested materials to be used instead of drywall. That’s where DC315 comes in. DC315 is an ICC-ESR-approved intumescent coating that acts as a spray foam fire protection layer.
IFTI’s data shows DC315 is evaluated under ICC-ESR 3702 and carries an IAPMO ER-0499 report confirming it meets IBC/IRC requirements as an alternative 15-minute thermal barrier over SPF. It has also been tested per AC 377 Appendix X as an ignition barrier for attic or crawlspace installations. In short, DC315 transforms bare foam into a code-compliant assembly, stopping flame spread long enough to let occupants escape.
Paint to Protect with IFTI this Holiday Season
For complete safety around hearths, remember that heat can affect more than just foam. Many fireplace surrounds use wood trim, plywood backing, or gypsum panels. IFTI offers DC360 intumescent paint for those combustible materials.
DC360 is a tested Class A flame-spread coating for wood and gypsum. It expands into a protective char when heated, preserving the integrity of trim, paneling or ceiling boards around a fireplace. Together, DC315 on the insulation and DC360 on wood surfaces can give remodelers and homeowners a comprehensive spray foam fire protection system for any fireplace wall or chase.