Vents, Grounding Hardware and Long Eave Lines
The roof of a depot building is mostly plain field, which makes the exceptions more important. Ventilators let the building breathe, and the flashing at their bases is a place where water can wick under a lap. Grounding and bonding hardware is fastened through the roof or along its edge, and each clip is a fastener that can back out as the metal moves in the afternoon heat. We inspect these hardware points one by one, because a roof that looks sound from the ground can have a dozen small openings along an eave.
Drainage is the second concern on big roofs. A winter season of rain has to leave a large storage roof through scuppers and gutters that are open and correctly sloped, and in Pasadena itself that season brings about 20 inches a year, with February the wettest month. We clear and rebuild scupper boxes, add a cricket where water sits behind a wall and replace gutter sections that have pulled apart, so a rainy week does not become a roof problem.
Fire Ratings, Embers and Hot Work Rules
Fire performance matters on any storage site that holds munitions, and Pasadena's rules show how a Class A roof is judged. The city's Fire Hazard Severity Zones run along the Arroyo Seco and north and west of the 210, and in the Very High zone the state requires a Class A roof assembly on new roofs and on reroofs above half the roof in a year, rated as a whole: the covering, the underlayment and the deck together. A mineral-surfaced cap sheet underlayment of at least 72 pounds is part of that rule. The Eaton Fire destroyed 9,419 structures in January 2025, which puts ember exposure on the list for any Pasadena roof.
A fire-rated roof is only as good as its seams, vents and edges, so those details get the same attention on a depot that a Class A assembly gets in a Pasadena fire zone. We also plan hot work as the exception, with fire watches, extinguishers and written permission from the station, and we choose assemblies that keep that exception small.
Gate Checks, Escorts and Ship Schedules
Working on a naval station means working to its calendar. Crews are generally vetted and badged, vehicles are searched at the gate, and escorts may follow workers around ordnance and waterfront areas. Loading operations at a pier can close roads and restrict areas for a day or more, and the roofing schedule has to move around them. We ask the station for its access routes, restricted hours and laydown areas at the outset, and we keep a second shift plan ready in case a closure removes a day.
Material handling needs the same thought. On a site of this size, long hauls from a gate to a roof can eat half a shift, so we stage rolls, panels and edge metal close to the building and sequence deliveries to match the crew. Temporary dry-in is always staged and used when a closure ends a shift early, because a roof left open over a depot will take whatever weather arrives overnight.
A Large Station Reroofed in Phases
With 230 buildings spread across thousands of acres, a station does not reroof everything at once. Roofs come due in sequence, and an owner needs to know which are next and what each will cost in time and disruption. A written condition report for each roof, with photographs, drain notes and an estimate of remaining life, makes that sequence practical. It is the same discipline we use to plan roof work across many sites, built on written condition reports for buildings spread across a large site.
Between replacements, upkeep carries more weight than people expect. Clearing drains, retightening hardware and resealing a worn joint twice a year costs little, and it pushes the next large expense further out. The same questions come up on depot and warehouse roofs elsewhere in the region and at Coast Guard stations such as Base Los Angeles-Long Beach on Terminal Island. Owners in Vernon, an exclusively industrial city about five miles south of downtown Los Angeles, meet many of the same large-roof concerns.
Commercial Roofing Questions
Why would a depot reroof avoid torch-applied membranes?
Open flame is commonly limited near ammunition and fuel, and the station sets that rule. Heat-welded single plies, mechanical attachment and cold adhesives avoid the issue. We learn the restrictions for each building before we recommend a system.
What does a Class A roof assembly mean?
It is a fire classification earned by the whole assembly working together. In California's Very High fire zones, the covering, underlayment and deck must meet it, and the details at vents and edges matter as much as the surface. We check the listing for the assembly before we propose it.
How are large storage roofs inspected on a station with many buildings?
Walk-through inspections cover edges, penetrations and drains, and drone flights can speed up the survey of big roofs where the installation allows them. Each roof gets its own written entry. That record lets a facilities office rank buildings by urgency.
Can a leak in a storage building be stopped without a full replacement?
Frequently, yes. Most leaks start at a penetration, seam or edge, and a rebuilt detail can hold for years if the membrane around it is sound. A moisture survey shows whether wet insulation is spreading, which would change the answer.
Does a ship loading schedule affect roofing?
Yes, because closures on roads and restricted zones can limit access for a whole day. We ask for the schedule in advance and shift crews to buildings outside the affected area. Roofs that must close that day are left watertight with temporary protection.
