Commercial Roof Inspection Checklist (Flat + Low-Slope): What to Check & How to Document It
A commercial roof inspection checklist needs to be more than a few bullet points like “look for ponding” and “check flashing.” On flat and low-slope roofs, small details (a split seam, a missing termination bar screw, a blocked scupper, a loose pitch pocket) can turn into big leaks fast — and those leaks can travel far from the point of entry.
This checklist is written for real on-site use: what to look at, what to photograph, what to measure, and how to describe conditions clearly in your report.
Important
If your SOP limits you to a visual inspection, say that clearly in the report. Commercial roofs often require specialized evaluation, core cuts, flood testing, IR scans, or manufacturer-authorized contractors.
Before You Step on the Roof (Safety + Scope)
- Confirm access method: ladder, hatch, interior stair, exterior stair, manlift.
- Check fall protection requirements: parapet height, tie-off points, anchors (if present), guardrails.
- Look for overhead hazards: power lines near access points, rooftop antennas.
- Weather conditions: wind, rain, frost/ice. If unsafe, document limitation.
- Verify what roof type you’re looking at: single-ply membrane (TPO/PVC/EPDM), modified bitumen, BUR, metal, SPF/foam, coated system.
Roof basics to record (always)
- Roof area(s) inspected (e.g., “Main roof over retail bay, rear low-slope roof over office”)
- Estimated roof age (if known) and visible layer count (re-cover vs. tear-off)
- Roof slope type (flat/low-slope) + approximate slope direction
- Roof covering type (visual identification)
- Drainage method (internal drains, scuppers, gutters)
Global Walk-Through Checklist (Start Here)
Do one slow lap and look for the “big four”:
- Openings in the system (holes, splits, punctures, missing patches)
- Water management issues (ponding, blocked drains/scuppers, poor slope)
- Edge failures (perimeter flashing, coping, termination bars)
- Penetration failures (pitch pans, boots, RTU curbs, vent flashings)
Photograph wide shots first, then work into close-ups.
Key Takeaway
Take a “roof map set”:
- 4 corner wide shots
- 1 shot of every drain/scupper
- 1 shot of every penetration cluster (RTUs, vents, pipe banks)
- Close-ups only after you’ve established context
Roof Covering (Membrane/Surface) Checklist
Single-ply membranes (TPO / PVC / EPDM)
Look for:
- Seam condition: fishmouths, peel-back, gaps, bridging, wrinkling at seams
- Punctures/cuts: especially around walk paths, tools, rooftop unit service areas
- Shrinkage (common in older EPDM): membrane pulling at edges/penetrations
- Blisters/bubbles: note size and location; may indicate trapped moisture or adhesion issues
- Surface degradation: chalking, cracking, exposed scrim (TPO/PVC)
How to document:
- “Membrane seam separation noted at northeast quadrant near RTU-2 (approx. 18 in). Recommend evaluation/repair by qualified roofing contractor.”
Modified bitumen / BUR (built-up roof)
Look for:
- Alligatoring, cracking, ridging, splitting
- Open laps and failed adhesive lines
- Exposed felts or granular loss (on cap sheets)
- Evidence of patching: quality, adhesion, compatibility
Coated roofs / SPF (spray foam)
Look for:
- Coating wear-through (thin spots, exposed foam)
- Foam damage (gouges, UV degradation, soft areas)
- Cracking/crazing in coating
Note
Coating systems are maintenance-driven. “No active leak observed” is not the same as “roof is in good condition.” Describe coating thickness/coverage condition visually and recommend maintenance where worn.
Flashing & Edge Details Checklist (Where Most Leaks Start)
Perimeter edges
- Metal edge/drip edge: secure, straight, fasteners present, no buckling
- Coping (parapets): seams sealed, no loose sections, no open joints
- Termination bars / reglets: fasteners tight, sealant intact, no gaps
Wall flashings
- Base flashing condition: adhered, not pulled, no voids
- Counterflashing: present where required, sealed, not loose
Photo checklist:
- One wide shot per elevation (N/E/S/W)
- Close-up of any open edge, lifted flashing, or failed sealant joint
Penetrations Checklist (Every Pipe, Every Curb)
Penetrations are where a “fine-looking roof” still leaks.
- Pipe boots: cracked, split, loose clamps, UV damage
- Pitch pans / pitch pockets: missing pourable sealer, dried/shrunk sealer, cracks/voids
- Electrical/conduit supports: proper blocks/supports, not rubbing membrane
- Exhaust vents: flashing intact, no corrosion holes, cap present
- Skylights: curb flashing condition, cracked domes, failed seals
Documentation language that helps:
- “Pitch pocket at conduit bank shows missing pourable sealer and exposed fastener heads. Leak risk. Recommend roofing contractor service.”
Rooftop Units (RTUs), Curbs, and Mechanical Areas
Inspect the roof around equipment like it’s a different roof.
- Curbs: counterflashing present, no gaps, sealant continuous
- Vibration damage: membrane abrasion around units from service traffic
- Condensate lines: discharging onto roof surface (can accelerate wear)
- Oil/grease contamination: around kitchen exhaust (can degrade certain membranes)
- Walk pads: present where service access is frequent; adhered and intact
Drainage Checklist (Drains, Scuppers, Gutters)
Water that can’t leave will find a way in.
- Internal drains: strainers present and secure, no debris buildup, signs of back-up
- Scuppers: open, not blocked, proper flashing at opening
- Overflow provisions: secondary drains/scuppers (if present) not blocked
- Gutters/downspouts: secure, seams sealed, debris-free
Ponding water
- Note location and size (approximate dimensions)
- Look for algae lines, silt rings, or staining that indicates repeated ponding
Key Takeaway
If you can, photograph ponding indicators even on a dry day (staining rings, debris lines). It’s more defensible than “ponding suspected.”
Signs of Active or Past Leaks (Roof + Interior Clues)
On-roof indicators:
- Staining around penetrations
- Rusted fasteners, degraded sealant, patched areas
- Wet insulation feel (soft spongy areas) — do not probe if not allowed
Interior indicators (if you’re inspecting the building too):
- Ceiling tile staining
- Mold-like growth around HVAC diffusers (also could be condensation)
- Wall staining at parapets
Documentation: What to Put in the Report
Minimum reporting set:
- Roof type and scope limitations
- Drainage method + condition
- 3–10 representative photos + close-ups of defects
- Clear recommendations (repair vs. evaluate vs. replace)
Example summary paragraph
“Commercial low-slope membrane roof observed with multiple maintenance-related deficiencies including open seam sections at perimeter, sealant shrinkage at pitch pockets, and debris at internal drains. Recommend evaluation and repair by a qualified commercial roofing contractor. Due to roof complexity and limited access to concealed components, this inspection was visual only.”
Quick Field Checklist (Copy/Paste)
- Safe access confirmed; limitations documented
- Roof type identified (TPO/PVC/EPDM/BUR/Mod-bit/SPF/coated)
- Wide shots taken (4 corners + overall)
- Membrane surface: seams, punctures, blisters, shrinkage
- Perimeter edges/coping/termination bars secure
- Wall flashings/counterflashings intact
- Penetrations: boots, pitch pockets, conduits, vents
- RTU curbs and mechanical areas wear/abrasion noted
- Drainage: internal drains/scuppers/gutters clear
- Ponding indicators documented
- Leak indicators noted (roof + interior)
- Clear repair/evaluation recommendations
Where ReportWalk Fits
If you’re trying to move faster without writing vague roof notes, ReportWalk helps you dictate defects in plain language, attach the right photos, and turn them into clean report-ready observations — especially useful on commercial roofs where documentation is everything.
