CSLB C-39 Roofing ContractorSafety and RepairMedium
A roofing contractor is repairing a persistent leak on a low-slope commercial roof. The leak appears to be originating near a rooftop HVAC unit. Upon inspection, the contractor observes that the base flashing around the unit is deteriorated and has several small cracks. Which of the following is the most appropriate initial repair strategy?
- AClean the area thoroughly, prime, and apply a compatible fluid-applied reinforcing membrane over the cracked flashing.
- BApply a new layer of asphalt emulsion over the cracked flashing.
- CRemove the entire HVAC unit to replace the base flashing with new sheet metal.
- DInstall a temporary tarp over the HVAC unit and surrounding area.
Show answer & explanationAnswer & explanation
Correct answer: A. Clean the area thoroughly, prime, and apply a compatible fluid-applied reinforcing membrane over the cracked flashing.
For small cracks and deterioration in base flashing, a fluid-applied reinforcing membrane is often the most effective and durable repair. It creates a seamless, watertight seal over the existing compromised flashing without requiring extensive demolition.
Why the other options are wrong
- B. Asphalt emulsion alone may not provide sufficient reinforcement or long-term waterproofing for cracks in flashing.
- C. Removing an entire HVAC unit is a significant, costly, and often unnecessary undertaking for repairing small cracks in flashing; it's a last resort for severe damage.
- D. A temporary tarp is not a repair; it only offers short-term protection and does not address the underlying flashing issue.
Cracked Flashing Repair
For minor cracks and deterioration in roof flashing, a fluid-applied reinforcing membrane system is an effective and common repair method.
- Creates a seamless, watertight seal.
- Avoids costly tear-off for minor damage.
- Requires proper surface preparation.
Memory trick: Cracks in flashing: clean, prime, then liquid-seal for a lasting fix, no need to peel.