A fire-rated underlayment is a material placed beneath flooring, roofing, or wall assemblies to improve fire resistance and slow the spread of flames in the event of a fire. It is commonly used in commercial and residential buildings where fire codes require additional protection.
Types of Fire-Rated Underlayment
- Roofing Underlayment
- Used beneath shingles, metal roofing, or tiles to provide fire resistance.
- Common materials:
- Fire-resistant synthetic underlayment (Class A-rated)
- Self-adhered modified bitumen sheets
- Fire-retardant treated plywood
- Flooring Underlayment
- Used under hardwood, laminate, vinyl, or tile flooring in multi-story buildings to meet fire safety regulations.
- Common materials:
- Cementitious board (e.g., Durock, HardieBacker)
- Gypsum-based underlayment
- Fire-rated soundproofing mats
- Wall & Subfloor Underlayment
- Installed under drywall or between layers of flooring to improve fire resistance.
- Common materials:
- Type X or Type C gypsum board
- Mineral-based fireproof boards
- Magnesium oxide (MgO) panels
Fire Ratings
- Fire-rated underlayments are classified based on their fire resistance:
- Class A (highest rating, best fire resistance)
- Class B (moderate resistance)
- Class C (basic protection)
For specific applications, always check local building codes (e.g., ASTM E108 for roofing, ASTM E84 for flame spread) and consult manufacturers for compliance with NFPA and UL fire ratings.
Are you looking for fire-rated underlayment for a specific use case like roofing, flooring, or walls?