When patching SFRM, which materials are allowed?

• A. Cementitious patch
• B. Water-based patch
• C. The same SFRM used on the project
• D. Different patch material

Answer: (C)

Patch repairs for sprayed fire-resistive materials must use the same SFRM that was originally applied on the project. Matching the material preserves the bond, curing behavior, and thermal properties, which keeps the fire-resistance rating and the system’s listing intact. Using a different patch material, such as a cementitious or water-based patch that isn’t the same SFRM, can introduce differences in strength, porosity, moisture handling, and thermal expansion. Those differences can lead to poor bonding, cracking, or delamination under heat, potentially reducing the effective fire resistance and voiding the listing. Therefore, the patch should be the same SFRM used on the project unless the manufacturer explicitly approves a different patch for this specific system.