On a hospital campus built in stages, the roof gives way first at the line where one building meets the next. A tower from one decade stands beside a wing from another, and the two roofs move at their own pace with the heat, so the seam between them opens and closes through every season. Water finds that joint long before it finds the field of either roof, and it drips into a corridor or a ward that has no way to close for repairs. Hospital roofing in Pasadena, CA is mostly the careful work of tying those roofs together: expansion joints, transitions, curbs and flashings that keep moving without letting go. We build each tie-in as its own piece of sheet metal and membrane detail, lapped and supported, so that the older roof and the newer roof can behave differently and still shed water the same way.
Hospital Roofing in Pasadena, CA
Where an Older Tower Meets a Newer Wing
Huntington Hospital shows how a medical campus grows. Its east tower dates to 1998, the west tower followed in 2008, and the emergency department was enlarged in 2014, so buildings of three different eras share a single site and their roofs meet wherever one ties into another. Roofs on buildings of different ages commonly differ in substrate, insulation thickness and repair history, and the joints between them are where leaks tend to start.
We survey these transitions first on any campus, because a joint that is leaking today will leak on a stormy night in February when the building is full. The repair usually means a new expansion joint cover with a flexible bellows, sheet metal flashing that laps over the membrane on both sides and terminations that can accommodate movement. Where an addition ties into an older roof, we check that drainage still works, since a new wall can dam water on the old roof. Our general approach to commercial roof repair applies, with one extra rule: no repair is left half-finished at night.
Plant Rooms, Air Handlers and Generator Pads
A hospital roof is a mechanical floor. Air handlers, exhaust fans, chillers, generator exhaust and pipe racks all sit above patient floors, and the roof beneath them is walked on constantly by engineers. Wear from that traffic, vibration from the larger units and the heat from exhaust all attack the membrane. Hospitals commonly use multi-ply systems, such as modified bitumen or built-up roofing, because a redundant layer buys time when something goes wrong.
We plan walkways, protect the sheet under every pad and rebuild equipment supports so the load lands on structure. Exhaust discharge locations matter as much as the membrane, since fumes and heat can age a roof at an outlet faster than the rest of it. When a unit is replaced, we expect to be called, because a new unit set without a roofer present has a way of leaving a new leak behind. The engineer gets a plan of the roof that shows every curb and every pipe.
Huntington, Kaiser and the Region's Medical Campuses
Huntington Hospital, in the HeArt District, is the San Gabriel Valley's only Level II trauma center, and Kaiser Permanente is another of Pasadena's largest employers. Other medical campuses across the region include USC Arcadia Hospital, a 460-bed facility in Arcadia, City of Hope in Duarte, AHMC San Gabriel Valley Medical Center in San Gabriel, Garfield Medical Center in Monterey Park, Providence St. Joseph Medical Center in Burbank and Adventist Health Glendale. Veterans Affairs has its own medical campuses in Los Angeles, and roofing at a VA medical center runs under federal access rules.
Each campus has its own roof history, and the larger ones carry many separate roofs. We write one condition report for the whole site, with every roof numbered and photographed, and the owner uses it to set a multi-year plan. A multi-site roof program carries the same structure across several campuses, and pricing against that plan keeps surprises few for healthcare systems with more than one site.
Infection Control, Intakes and Continuous Operations
A ward cannot be emptied for a roof, so every step has to protect the people below. Before work begins, we meet with the hospital's infection prevention team and facilities engineers, mark every air intake and exhaust, and agree on containment where work crosses a ceiling. Fumes are managed by favoring welded and low-odor methods and by never allowing hot work near intakes. Noise and vibration are scheduled around surgery, imaging and quiet units.
Roofing sequences are written so that each section is dry, sealed and tested before the day ends, and temporary roofing is ready if weather turns. The same discipline runs through our occupied building reroofing, applied here at a larger scale, and the smaller medical office roofs follow it too. Pasadena's winter rain season, with February the wettest month, means a hospital reroof is usually planned for the dry months, with a standby crew on call for the rest of the year.
Code Changes, Fire Zones and Wind Events
The 2025 California Building Standards Code, including the Existing Building Code, applies to Pasadena permits filed from January 1, 2026 onward, so a roof permit for a hospital is reviewed against it. A campus inside a mapped Very High Fire Hazard Severity Zone must use a Class A assembly on a new roof and on a replacement above half the roof in a year. After the Eaton Fire and the Santa Ana wind forecasts that preceded it, edge metal, equipment tie-downs and roof drainage deserve a look on every building, and we include those items in each survey so the plan covers fire, wind and rain together.
Commercial Roofing Questions
Which part of a hospital roof should be looked at first?
Begin with the joints between buildings of different ages. Expansion joints and tie-ins between towers, wings and additions move the most and fail the earliest. A survey of those, followed by plant roofs and drains, finds the leaks that matter before the next storm turns a small drip into a ward closure.
Can a hospital reroof be done without moving patients?
In nearly every case, yes. Patients stay where they are because the roof is closed section by section, each sealed and tested daily. We coordinate with infection prevention and facilities, protect every intake and keep noisy work away from surgery and imaging hours. Some interior protection may be needed at ceilings.
Why do new equipment installations cause roof leaks?
Mechanical crews cut and set curbs on a schedule that does not include flashing. A new unit raises the roof detail one more time, and a roofer should be present to flash it. We ask hospitals to include a roofing sign-off in each equipment change, and we provide one.
What does a campus roof program look like over several years?
Priorities set the order. We number every roof, rate its condition, and group the work into what is urgent, what can wait for the dry season and what belongs in the capital budget. Each year the plan is updated with new survey data, so the facilities team sees the same picture the finance office does.
How is a leak in an emergency department handled at night?
We answer at any hour and go to the roof with temporary materials, because water above a trauma bay cannot wait for the morning. The first goal is to stop the water and protect the space below, and the permanent repair follows in daylight. Our crews carry the tools to dry the deck, make a watertight patch and report what failed.
Walk the Joints With Us
Tell us which towers and wings concern you. We will look at the tie-ins, plant roofs and drains on your hospital roof, because the details decide whether the roof lasts, and we will put our findings in writing. Call at any hour if water is reaching a patient floor.