Commercial roofing · Inspections
Commercial roof inspections and moisture surveys
A roof inspection is only worth what it finds. This page describes what we actually look at, which instrumented methods we use and the standards they follow, and what lands in the written report - so you can tell the difference between an inspection and a sales visit with a ladder.
- CA Licence #1052777
- We price match like-for-like bids
- 5–10 years on labor and workmanship
Start here
Four different things get called "an inspection"
They cost different amounts, answer different questions, and are not substitutes for each other. Tell us which question you are trying to answer and we will tell you which one you need.
You want to know how much roof you have left
Condition assessment
A walked survey of the whole roof — membrane, seams, flashings, curbs, penetrations, edge metal, drainage, and rooftop equipment — documented with photographs and a plan showing where each deficiency is. This is the inspection that feeds a capital plan and a maintenance budget, and the one most owners should be buying twice a year.
You need to know how much of the insulation is wet
Moisture survey
A non-destructive scan of the roof to map wet insulation, verified with test cuts. This is the single most decision-relevant test on a low-slope roof, because it is what separates a restoration candidate from a tear-off, and it is the test almost no coating bid includes.
Water is coming in and nobody can find where
Leak investigation
Leaks rarely enter the building anywhere near where they enter the roof. Water tracks along deck flutes, purlins, and conduit before it shows up on a ceiling tile. Investigation means working backward from the interior evidence with water testing and, where the membrane warrants it, electronic leak detection.
You are buying, selling, or refinancing
Due diligence and transaction surveys
A roof report written to sit inside a property condition assessment: remaining useful life, immediate repair costs, replacement reserve, warranty status, and code exposure at the next roof event. That last item is where deals get repriced, and it is usually the item nobody has scoped.
Methods
How the roof actually gets tested
Each of these has a published standard behind it and a set of conditions under which it produces valid results. Any contractor can own a thermal camera. Running a survey that means something is a different matter.
Walked visual survey with photo documentation
Nothing replaces walking every square of the roof. Split seams, backed-out fasteners, open laps, failed pitch pockets, cut membrane from equipment work, crushed insulation under walk paths, and stripped sealant at counterflashing are all visible if someone actually looks. The value is in the discipline and the documentation, not the technology.
Infrared thermography (ASTM C1153)
Wet insulation holds heat longer than dry insulation. After the roof has been thermally loaded by a day of sun, the wet areas radiate longer into the evening and show up on a thermal image. The standard practice for this is ASTM C1153, Location of Wet Insulation in Roofing Systems Using Infrared Imaging, and it sets real conditions: the roof has to be dry with no appreciable precipitation for roughly the prior 24 hours, the survey is run after sunset while the thermal contrast is still present, wind has to be low, and there has to be enough temperature differential to produce a signal. A survey run in the wrong conditions produces a clean-looking image and no information.
Electronic leak detection (ASTM D7877, ASTM D8231)
ASTM D7877 is the standard guide for electronic methods of detecting and locating leaks in waterproof membranes, covering low-voltage scanning, low-voltage vector mapping, and high-voltage spark testing. ASTM D8231 is the standard practice for low-voltage electronic scanning specifically. These methods find actual breaches in the membrane rather than inferring them, which is what you want on a roof that keeps leaking after two rounds of patching.
Test cuts
Destructive, small, patched the same day, and irreplaceable. A cut tells you the number of layers actually on the deck — which is a code question that determines whether a recover is even legal — plus the insulation type and thickness, whether it is wet, what the fastening pattern is, and the condition of the deck. Non-destructive methods point at where to cut. They do not replace cutting.
We scope the method to the question. A 12,000 sq ft retail roof with one leak does not need a full instrumented survey; a 300,000 sq ft distribution roof headed for a capital decision absolutely does. We will tell you which, including when the answer is the cheaper one.
Scope
What gets looked at, component by component
| Field membrane | Splits, blisters, ridging, granule loss, shrinkage, punctures, prior repairs and what they were made with |
|---|---|
| Seams and laps | Open laps, fishmouths, edge peel, seam probing on single-ply |
| Flashings | Base flashing height and attachment, counterflashing, termination bars, stripped or missing sealant |
| Penetrations | Pipe boots, pitch pockets, conduit supports, gas lines, structural supports set directly on the membrane |
| Rooftop equipment | Curb condition, unit pans and condensate discharge, equipment that has been serviced by cutting the roof |
| Drainage | Drain sumps, strainers, scuppers, overflow provisions, standing water 24+ hours after rain and its extent and depth |
| Edge metal and parapets | Coping joints, gravel stop, fascia attachment, wall cap and through-wall flashing |
| Deck and structure | Deflection, ponding that indicates a structural problem, corrosion on steel deck visible from below |
| Safety and access | Hatch and ladder condition, skylights and smoke vents, fall exposure at edges and openings |
| Documentation | Existing warranty status, prior repair history, layer count, and what the last contractor actually did |
Every deficiency gets located on a roof plan and photographed. A finding you cannot point to on a drawing is a finding nobody will ever act on.
Timing
When to inspect, in this climate
The NRCA recommends inspecting a roof system at least twice a year, preferably spring and fall, and after any major weather event. In Southern California and the southern Central Valley that recommendation maps onto a very specific calendar.
Late spring: find out what winter did
Atmospheric rivers do the damage here, and they do it in a few days. The post-season walk finds the seams that opened, the flashings that leaked without anyone noticing inside, and the areas that held water long enough to tell you the drainage is failing.
September through December: get ready
This is the window that matters and it is the one everyone misses. Drains and scuppers cleared, strainers in place, open seams and flashings repaired, and any coating or restoration work completed while the substrate is reliably dry. By the time it is actually raining, every roofer in the county is booked on emergencies and you are in the queue behind them.
The Kern County wrinkle
Roughly seven inches of rain a year and long, punishing summers means the failure mode here is heat and UV rather than water. Agricultural processing facilities add a second one: exhaust, dust, and organic debris loading on large flat metal and low-slope roofs, which blocks drainage and holds moisture against the surface long after a rain event has passed. Those roofs need the drainage inspection more than most, and almost nobody is doing it for them.
The economics
What an inspection is actually protecting
The value is not in finding leaks. It is in finding the conditions that become leaks, before water reaches insulation — because once insulation is wet, the decision changes category. A dry roof with a spent surface is a restoration candidate at a fraction of replacement cost. The same roof with wet insulation across the field is a tear-off.
That is the whole argument. An inspection program is what keeps your roof on the cheap side of that line for as long as possible.
It also protects the paperwork. Manufacturer warranties carry maintenance and notification conditions, and a documented inspection history is what demonstrates you met them.
- Wet insulation is the line — on one side, restoration; on the other, replacement
- Damage is usually caused by trades — HVAC, solar, telecom, not weather
- Drainage failures compound — a blocked drain in November costs more than a roof crew in October
- Warranties have conditions — documentation is how you keep yours
- Capital planning needs numbers — remaining life, not a guess
Why call Green Coast
Credentials and starting price
- Two CSLB classifications - C-39 (Roofing) and B (General Building), in business since 2019.
- Progressive Materials Certified Licensed Applicator since 2024, so a moisture survey that finds a restoration candidate can go straight into a specification we can warranty.
- California license #1052777 - licensed, bonded, and insured. Verify it at cslb.ca.gov.
Commercial roof inspections start at $595. That is a starting point, not a flat rate - roof area, access, and which of the four inspection types above you need all move the number. Call 661-578-3346 with the building and we will price it.
What you end up with
A roof plan with deficiencies located and photographed, a remaining useful life estimate, and recommendations split into immediate repairs, deferrable items, and capital planning - something your engineer or asset manager can act on directly.
Where we work
Commercial inspections across Los Angeles County and Kern County, plus Orange, San Bernardino, and Riverside counties. See the full service area.
Questions property managers ask
How often should a commercial roof be inspected?
The NRCA recommendation is at least twice a year, ideally spring and fall, plus after any major weather event. In our service area that translates cleanly: one visit after the rains stop to see what the winter did, and one before they start to make sure the roof and the drains are ready. Buildings with heavy rooftop equipment, frequent trade access, or a membrane past fifteen years justify more frequent visits, because most of the damage on those roofs is caused by people, not weather.
What is the difference between an infrared survey and a moisture meter reading?
Infrared imaging under ASTM C1153 maps thermal anomalies across the whole roof and is fast over large areas, which is why it is the right tool on a 200,000 square foot distribution roof. Capacitance and nuclear meters take point readings and are useful for confirming a specific location. Neither one measures water directly — they both measure a proxy for it, which is why every anomaly worth acting on gets confirmed with a test cut.
Can you inspect a roof another contractor installed or warrantied?
Yes, and it is a normal request. Two cautions worth knowing. Cutting into a roof that is under a manufacturer warranty can affect that warranty, so we confirm warranty status and coordinate with the manufacturer before any destructive testing. And if the existing installer is still responsible for a defect, the useful outcome of the inspection may be documentation that makes them fix it, not a proposal from us.
Do you charge for inspections?
A walked condition assessment as part of scoping work we are bidding is part of doing business. A full instrumented moisture survey, a leak investigation with water testing, or a transaction report is professional work with real cost behind it and is quoted as such. Anyone offering a free infrared moisture survey on a large roof is either not doing one or is pricing it into something else.
What does the report look like?
A roof plan with numbered deficiencies located on it, photographs keyed to those numbers, the condition of each roof component, drainage findings, moisture survey results where one was performed, remaining useful life, and recommendations separated into immediate repairs, deferrable items, and capital planning. Written so a facilities director can act on it and an asset manager can budget from it.
Request a roof evaluation
Tell us the building, the roof area, and what you are trying to find out — a condition report, a moisture survey, a leak nobody can locate, or a roof report for a transaction. We will scope the right inspection for the question.
Green Coast Builders · CA License #1052777 · Serving Los Angeles, Commerce, City of Industry, Anaheim, San Bernardino, Riverside, Bakersfield, and Ridgecrest.