Leak Diagnosis, Roof Inspection & the Site-Specific Fall-Protection Plan

Welcome

Hello, and welcome. This is Super Structures General Contractors — a national general contractor headquartered in Powhatan, Virginia — here to help you and your clients build something that lasts. We're glad you're with us, and we look forward to connecting with you.

Alright, Leak Diagnosis, Roof Inspection & the Site-Specific Fall-Protection Plan. Don't let the plain title fool you. Here's the part that actually matters on the job: Finding a leak is detective work on how water moves through an assembly, routine inspection is what keeps a roof and its warranty alive, and neither happens safely without a fall-protection plan written for that specific roof. Learn it well and you become the service technician, the inspector, and the foreman owners call back by name.

The intro course covered OSHA Subpart M. This lesson goes to the roof itself: finding where water gets in, inspecting so it never starts, and planning fall protection for the roof you are standing on.

How water moves before it shows up

The drip in the ceiling is almost never under the hole in the roof. Water that enters at a flashing runs along the vapor retarder, down the flutes of a steel deck, or along a conduit, and drops where it meets an obstruction, often 20 or 30 feet from the entry. Several things look like roof leaks and are not: condensation on cold ductwork, a clogged HVAC condensate line, a skylight gasket, and a wall leak above the roof line. Timing is a clue: a leak only in wind-driven rain points to a wall or counterflashing facing the wind; a leak after snow points to an ice dam or a low flashing; a leak on a clear cold day is condensation.

The leak call, step by step

• Interview the occupant: when it started, what weather triggers it, and whether it follows recent rooftop work.
• Map the interior location on the roof plan, then go to the roof and look uphill of that point.
• Walk the details first: drains, boots, curbs, pitch pockets, flashing terminations, edge metal, and every seam uphill. Look for open laps, voids at T-joints, cracked boots, backed-out fasteners, and punctures.
• Water test with a hose from the lowest suspected detail upward, one detail at a time, with someone inside watching.
• Use electronic leak detection (ASTM D7877) on membranes over conductive decks to pinpoint breaches a hose cannot, and a flood test (ASTM D5957) only where the structural engineer has approved the load.
• Repair with the same material, to the manufacturer's detail, and document the location, cause, and fix with photos.

Moisture surveys and core cuts

When the question is bigger than one leak, the roof gets a moisture survey. An infrared survey (ASTM C1153) is done at night after a sunny day, when wet insulation shows warmer than dry; nuclear and capacitance meters read moisture on a grid where infrared cannot see through gravel or ballast. Every survey is confirmed by core cuts at wet and dry locations, logged, photographed, and patched the same day. The result is a roof plan showing wet area by percentage, which decides between repair, recover with wet insulation removed, and tear-off.

The routine inspection that keeps the warranty

NRCA recommends inspecting a low-slope roof twice a year and after any major storm, and most NDL warranties require documented maintenance. The inspection is a walk with a checklist and a camera: drains and strainers clear, seams probed where the roof moves most, flashing terminations and sealant intact, pitch pockets full, edge metal and coping tight, and no new penetrations, sleepers, or dragged-equipment damage from other trades. Repairs go to the approved contractor and into the maintenance log.

A fall-protection plan written for this roof

Subpart M gives the rules; the plan applies them to the building in front of you, in writing, before the crew arrives.

• Anchors — permanent anchors on commercial roofs, ridge anchors screwed through the sheathing into rafters or trusses on houses, and horizontal lifelines designed by a qualified person. Every anchor supports 5,000 pounds per worker or is engineered to a factor of two, and nobody ties off to a vent stack, a gas line, or a rooftop unit.
• Leading edge and the deck during tear-off — the edge moves as the old roof comes off; workers at it use leading-edge-rated self-retracting lifelines or stay behind a guardrail, and deteriorated deck is treated as a hole until it is replaced.
• Skylights, hatches, and openings — screened, covered and marked, or guarded before work starts.
• Warning lines and the hoist zone — warning lines at 6 feet, 10 feet where the hoist or conveyor runs perpendicular, PFAS or a guardrail for anyone between the line and the edge, and a barricaded drop zone at the base of the hoist and debris chute.
• Rescue — a written method for getting a suspended worker down in minutes.
• Weather and the lone technician — wind limits for handling sheets, no work on frost or wet membrane, a heat plan with water and shade, and a rule that the service tech who goes up alone is still tied off and still checks in.

Going Deeper (Intermediate)

Most low-slope leaks trace to flashings and penetrations, and most of those to work done after the roof was finished. The inspection that matters most is the one after another trade leaves the roof. A roofer who photographs the roof at turnover, and again after other trades finish, has the evidence that decides who pays for the repair.

Advanced / Pro-Level

Pros run a roof asset program: every roof with its age, system, warranty number, survey history, and repair log, budgeted for replacement before it fails. The pro foreman treats the site-specific plan as a document the crew signs, audits daily, and updates when the hoist moves or the tear-off reaches the next bay. For the general contractor, the roofer's plan and the GC's roof access control are one system: nobody from another trade goes onto the roof without the roofer's knowledge, a tie-off, and a sign-in.

Practice Challenge

A tenant reports a drip from a steel deck 25 feet from the nearest rooftop unit, only during storms with wind from the west. The roof is a five-year-old mechanically attached TPO with an NDL warranty, and an antenna was installed on the west parapet last spring. Where does the technician look first, and what else matters? (Answer: uphill and west of the drip, at the antenna mount and the coping and counterflashing on the west parapet; the technician water-tests those details one at a time with a watcher inside, repairs with TPO to the manufacturer's detail, documents the cause as other-trade damage for the warranty file, and does all of it tied off to a rated anchor with the hatch and roof edge protected.)

In Practice

A technician who interviews the tenant, maps the drip, walks uphill to the details, and water-tests one point at a time finds the leak in an hour and fixes it once. A technician who smears mastic over the seam above the stain comes back after every storm.

Common Mistakes to Avoid

• Patching directly above the interior drip instead of tracing the water uphill
• Repairing a membrane with roof cement or a sealant the manufacturer does not approve
• Skipping core cuts to confirm a moisture survey before deciding on a recover
• Treating the fall-protection plan as a generic form instead of a plan for this roof
• Letting a service tech or another trade on the roof alone without a tie-off and a check-in

Takeaway: Finding a leak is detective work on how water moves through an assembly, routine inspection is what keeps a roof and its warranty alive, and neither happens safely without a fall-protection plan written for that specific roof.

Educational content only — not roof design, engineering, legal, or safety advice, and not a substitute for hands-on training under a licensed roofing contractor or the judgment of a licensed design professional. Follow the IRC, IBC, and plumbing code as adopted and amended in your jurisdiction, OSHA 29 CFR 1926, the manufacturer's installation instructions and warranty requirements, and your company's procedures.