How to Use: Inspect from the ground or safe access—use binoculars, camera extension pole, or drone for high areas. Never climb a ladder without training or permission. Start with the perimeter for drainage, then check roof edges for flashing. Ask manager: “Last inspection? Warranty documents?” Mark High (standing water, torn roof covering), Medium (cracked flashing, debris), or Low (clean, maintained) risk. Commercial roofs fail in 80% of claims from water damage (Factory Mutual Global 2024); average leak costs more than $50,000 in repairs. Focus on Factory Mutual Data Sheet 1-28/1-29 (roof systems and deck securement) and National Roofing Contractors Association guidelines.
THE BASICS: WHY COMMERCIAL ROOFS FAIL
Commercial roofs are usually flat or low-slope systems covering large buildings like warehouses and offices. Common types: built-up roofing, modified bitumen, single-ply (TPO, PVC, or EPDM), metal panels, and spray foam.
Top Hazards (Factory Mutual Global/National Roofing Contractors Association 2025):
- Water intrusion – 40% of losses (leaks from seams or equipment openings let water soak insulation and damage structure).
- Wind uplift – tears roof covering in storms (causes more than $1 billion in damage yearly).
- Hail or impact – dents metal panels and cracks insulation, creating entry points for water.
- Fire – from torch installation or flammable materials near heat sources.
Key Numbers: 75% of failures come from poor installation or lack of maintenance (National Roofing Contractors Association); wind events up 20% (Factory Mutual Global). Lifespan: 15–30 years with proper care.
Your Goal: Spot weak points—prevent small leaks from turning into mold, rot, or roof collapse.
INSPECTION CHECKLIST
DRAINAGE & WATER CONTROL CHECKLIST
Why Check: Standing water for more than 48 hours weakens the roof structure (Factory Mutual Data Sheet 1-28).
- Drains and overflow scuppers: clear of debris, no clogs, screens in place Why: Blocked drains trap water and overload the roof.
- Slope: at least 1/4 inch per foot, no low spots holding more than 2 inches of water Why: Flat areas collect water and cause sagging.
- Gutters and downspouts: firmly attached, no leaks, water exits more than 10 feet from foundation Why: Leaking gutters rot walls and erode soil.
- Standing water: none after rain, no water stains on ceilings below Why: Persistent water damages insulation and deck.
- Crickets and tapered insulation: guide water to drains Why: Directs flow and prevents pooling.
ROOF COVERING & SURFACE CHECKLIST
Why Check: Seams are the first to fail in single-ply roofs (National Roofing Contractors Association).
- Tears or blisters: no punctures, bubbles, or cracked “alligator” patterns Why: Openings let water in and weaken the roof.
- Seams: fully sealed, no gaps wider than 1/8 inch Why: Gaps allow wind and water entry.
- Ballast or gravel: even coverage, no bare spots or wind-blown piles Why: Uneven ballast lets wind lift the roof.
- Protective coatings: smooth and attached, no peeling or chalking Why: Coatings block sun damage and leaks.
- Hail damage: no dents in metal or cracks in foam Why: Impact holes start leaks.
FLASHING & PENETRATIONS CHECKLIST
Why Check: 90% of leaks start at edges or equipment (Factory Mutual Global).
- Edge flashing: tight and rust-free, no lifts or separations Why: Loose flashing lets wind peel the roof.
- HVAC curbs: sealed boots around units, no gaps Why: Gaps let water enter around equipment.
- Pipes and vents: counter flashing covers base, caulk not cracked Why: Failed seals leak into the building.
- Skylights and hatches: no fog inside, seals tight Why: Broken seals cause condensation and leaks.
- Expansion joints: flexible material intact, no splits Why: Rigid joints crack with building movement.
INSULATION & DECK CHECKLIST
Why Check: Wet insulation loses heat resistance and causes deck to sag (National Roofing Contractors Association).
- Insulation: firm, no soft spots under foot traffic Why: Compressed or wet insulation fails.
- Deck: no rust or sag (steel), rot (wood), or cracks (concrete) Why: Weak deck can collapse.
- Fasteners: tight, no pulled-out screws (wind test Factory Mutual 1-90 or higher) Why: Loose fasteners let wind lift the roof.
- Vapor barrier: present in humid areas, no tears Why: Stops moisture from inside the building.
- Walk pads: around equipment, non-slip surface Why: Protects roof from foot traffic damage.
MAINTENANCE & FIRE SAFETY CHECKLIST
Why Check: Yearly checks cut failures 50% (Factory Mutual Global).
- Debris: clear leaves, tools, or trash—no fuel for fire Why: Debris traps water and sparks fires.
- Fire rating: Class A or B materials, no torch work near edges Why: Low-rated materials burn fast.
- Access: hatches locked, no unauthorized people on roof Why: Prevents damage from extra traffic.
- Warranty log: annual inspections recorded Why: Proves maintenance for claims.
- Green roofs: watered, no dry plants (fire risk) Why: Dry vegetation ignites easily.
QUESTIONS TO ASK MANAGER
- “When was the last roof inspection? Show report.”
- “Any leaks or repairs in the last 5 years? Details?”
- “Wind and hail rating—Factory Mutual approved? Proof?”
- “Maintenance contract—who cleans drains?”
- “Equipment added? Flashing updated?”
RISK LEVELS
- High = Standing water, torn roof covering, active leaks → Suggest attention immediately, fix now
- Medium = Loose seams, debris buildup → Schedule repairs in 30 days
- Low = Well-drained, fully sealed, logged maintenance → Best practice
LCA Certified Inspector “Drain it. Seal it. Secure it.” Download PDF | Share via App
Resources:
- Factory Mutual Global Data Sheet 1-28: Roof Systems
- Factory Mutual Data Sheet 1-29: Roof Deck Securement
- National Roofing Contractors Association Commercial Roofing Guidelines
- Insurance Institute for Business & Home Safety Wind Uplift Prevention
Disclosure: This guide highlights common risks but is not exhaustive. Always verify local codes and carrier guidelines.