How often should a commercial roof be inspected?

The baseline schedule

When	Why
Early fall, before the rain season	Clear drains, verify flashings and sealants before Southern California's wet months
Spring	Assess winter damage, ponding evidence, blistering and open seams
After any major storm or high wind event	Wind uplift at edges and corners, debris damage, displaced ballast or coping
After rooftop equipment work	HVAC and solar contractors cause a large share of new leaks; verify curbs, penetrations and traffic damage
Before purchase, refinance or lease signing	Establish condition, remaining life and replacement reserve

Why semiannual, not annual

Roof failures are almost never sudden. Ponding at a clogged drain, a lifted seam, an unsealed pitch pan or a cracked pipe boot begins as a $300 repair and becomes a $40,000 insulation replacement after two wet seasons, because saturated insulation does not dry out - it spreads. Two inspections a year catch those conditions inside a single season instead of after several.

Warranty obligations

Manufacturer NDL and material warranties on single-ply and modified bitumen systems typically require the owner to maintain the roof, keep drains clear, and use approved contractors for any modification. Warranty claim denials commonly cite unauthorized penetrations - a solar array or new RTU curb installed by someone other than an approved applicator - and absence of maintenance records. Written inspection reports with photographs are what preserve the claim.

What each inspection should cover

• Drains, scuppers, overflows and evidence of ponding
• Field membrane, seams, laps and fastener backout
• Base flashings, counterflashing, coping, edge metal and terminations
• Every penetration: curbs, pipe boots, pitch pans, conduit supports, solar attachments
• Signs of traffic damage and debris from equipment servicing
• Interior ceiling staining beneath the roof plane, which is the truth-teller

Documentation is the point

Keep a roof file: dated inspection reports with photographs, every repair invoice, the warranty documents, and any equipment installation permits. When you sell or refinance, that file is worth real money - a buyer's inspector who can see maintained history will report a longer remaining service life, and remaining life is what drives the reserve number in the report.