Laboratory Exhaust and Crowded Penetrations
A laboratory roof is usually far busier than the roof over a classroom hall, with exhaust fans, ductwork, pipe supports and conduit crowding the membrane, and on a campus where newer labs such as Caltech's Cahill Center and Broad Center share ground with halls from the 1917 plan, a facilities office is caring for both kinds of roof at once. Each penetration is a place for a boot to split and a seal to age, and corrosive exhaust attacks sealants and some membranes faster than weather does. Where fume exhaust blows across the surface, we often specify a PVC roofing system, which is made to resist chemical and grease exposure better than many other single-ply sheets.
Construction itself is a source of leaks. Caltech reported spending $398 million on construction and renovation from 2020 to 2024, and every new unit, duct or line added to an existing roof is another cut through the membrane. We coordinate with general contractors and mechanical trades so each cut is flashed before the next trade arrives, and we walk the roof afterward to find the corners that were missed.
Sequencing Around Terms, Labs and Residence Halls
Pasadena City College puts a student body of well over twenty thousand on its Colorado Boulevard campus, so any reroof on a campus that size happens over a crowd. We stage the work so entries stay open, deliveries come and go outside peak class changes, and the area beneath active tear-off is closed and signed. Residence buildings, which we treat the way we treat apartment roofing, get a posted schedule so residents know which mornings will be loud.
Laboratories need more than a schedule. Some have vibration-sensitive equipment, and nearly all have air intakes close to the roof. We ask the facilities group for quiet hours and intake locations at the walkthrough, protect or temporarily cover the intakes, and choose low-odor adhesives or mechanically attached systems near them. That kind of occupied building reroofing keeps the building open and the research uninterrupted.
Heat, Fire Season and Rooftop Solar
The Eaton Fire in January 2025 forced JPL, which Caltech manages, to close and evacuate, and the wind forecasts that preceded it put Santa Ana gusts at 60 to 80 mph. A roof in that exposure is tested at its edges. Edge metal, rooftop equipment and vents are the parts that an ember or a lifted flashing can reach first, and in Very High zones a Class A roof assembly is required on a new roof and again whenever a reroof takes off over half of the existing one within twelve months.
Heat is the quieter problem. A recorded June high of 113 F and late-season heat waves flex membranes day after day, and a roof carrying solar equipment has even less room for a failure. Caltech completed a 1.3 MW solar array in 2010, and any campus that mounts panels on a roof should be sure the membrane under them will outlast the panels. Our solar-ready roofing work replaces or restores the roof first, then sets the mounts and flashings so nothing has to be torn up later.
Renewing a Campus in Stages
No campus can reroof everything at once, and a bond-funded or grant-funded project usually comes with its own schedule and reporting. Part of the money behind Pasadena City College came from a 2003 bond of about $150 million, and a project paid for that way tends to need scope documents that stand up to review. We deliver written condition reports with photographs, moisture findings and a ranked list, so a facilities office can put the roofs that will fail first into the next funded phase.
From there the plan runs as a roof capital planning schedule that the budget office can read. Between phases we clear drains, reseal openings and reseat the counterflashing that moves each summer. School districts phase their K-12 school roofing the same way, one funded package at a time. The adopted plan for Lamanda Park supports research and development alongside light-industrial and creative-business uses; those owners can use the same phased condition record to coordinate roof work with renovations.
Commercial Roofing Questions
Can reroofing happen over a laboratory without disturbing experiments?
Usually, with planning. We learn which rooms have sensitive instruments, where the exhaust and intake openings are, and which hours are quiet. Tear-off noise and vibration are scheduled around those windows, and fumes from adhesives and hot work are kept away from the intakes. If a room cannot tolerate any vibration, we propose a quieter method for the area above it.
How do you keep adhesive odors out of lecture halls and dorm rooms?
We start by choosing systems that carry less smell, such as mechanically attached sheets and low-odor adhesives. Then we locate each air intake, cover or protect it while the work is near, and time the application for hours when the rooms below are empty. Residents and staff get a notice of which days the work is closest to them.
Our buildings are from several eras. Can the new roof match the old parapets and trim?
Often yes, because the visible metalwork is formed by hand to the profile that is already there. Coping, cornice caps and scuppers can follow the existing shapes and finishes, and we can use materials that read like the original from the ground. The membrane behind them is modern, because that part is where performance matters most.
Should a roof be replaced before solar panels are installed on it?
If the membrane is within a few years of the end of its life, yes. Lifting an array to reroof beneath it means paying twice for the panel work, and a leak hidden under rows of racking is slow to trace. An infrared moisture survey and a condition report tell us how much service life is left before the mounts go on.
Which campus roofs should be repaired first when funds cover only a few?
Start with the roofs over the rooms that cannot get wet: laboratories, archives, performance spaces and server rooms. Then take the roofs with active leaks or wet insulation, then the ones near the end of their service life. A ranked report puts each roof in that order and states the reason, which makes the budget conversation shorter.
