Defects, repairs, and corrective actions
Typical defects
Common SFRM defects include thin areas, low density from over-watering or dry spray, delamination, cracking, sloughing, voids at welds or connections, damage from other trades, and water or freeze damage. Each has a cause: surface contamination, wrong temperature, excessive pass thickness, poor mixing, or physical abuse. The inspector should identify the defect, determine its extent, and require a repair that addresses the cause, not just the appearance.
Repair and verification
Remove loose or damaged material back to sound, bonded SFRM, clean the substrate, and reapply the same product or an approved equal in accordance with the manufacturer's instructions. Feather edges, allow proper set time, and protect the repair. Re-inspect thickness and density, and repeat bond testing where the repair is large or the original failure was adhesive. Document the area, product, method, and test results.
Worked example
A duct installer knocks a 4 ft² patch off a beam. The contractor proposes painting the exposed steel with a 'fireproofing patch.' Correct call: reject the paint, remove all loose material to a firm edge, clean the steel, reapply in ½ in. passes, and verify four thickness readings averaging at least the design thickness with no reading below the project's minimum. If the patch exceeds the project's threshold, add an E736 test.
Traps
Patching over delaminated material; using a different product without approval; skipping re-test after repair; accepting 'it looks thick enough'; failing to issue a corrective-action report.