May 15, 2026
SoMa's commercial flat roofs do more work than almost any other roof inventory in San Francisco. They host HVAC equipment, solar arrays, satellite dishes, roof decks, and sometimes all of the above. They sit in one of the warmest and sunniest microclimates in the city. And they have multiple contractors walking on them every year — for HVAC service, solar maintenance, AT&T installs, and more. The result: SoMa flat roofs need a maintenance cycle, not just inspections.
Our recommended SoMa commercial maintenance program is twice yearly, timed to the seasons. The first visit, in late spring after pollen drop and before summer heat, focuses on cleaning every drain and scupper, removing debris dams behind parapet walls, checking every seam and termination bar, and re-sealing any flashings that have lifted from thermal cycling. The second visit, in late fall before the rains, repeats the drain clearing and adds a full inspection of HVAC penetrations, solar array attachment points, and any equipment that's been added or moved during the year.
On TPO single-ply, the most common SoMa failure modes are seam lift at field-welded laps (especially around HVAC curbs where foot traffic is heavy), punctures from dropped tools or sharp HVAC components, and termination bar fastener pull-out at parapets. All three are catchable in a 90-minute biannual visit and repairable in another 30 minutes. Catching them early is the difference between a $200 repair and a $4,000 interior water damage claim.
On modified bitumen and built-up systems (still common on older SoMa buildings), the failure pattern is different: granule loss in high-sun areas, alligatoring of the top coat, and seam separation at laps that have been walked on too many times. These also benefit from biannual maintenance — granule replacement and a fresh aluminum-pigmented coat can extend service life materially when done before the underlying bitumen has actually failed.
Drainage is the universal issue. SoMa rooftops collect dust, leaves blown in from street trees, HVAC filter debris, and bird nesting material — and clogged drains turn even a perfectly-installed roof into a swimming pool that finds every weak point. Half the SoMa leak calls we go on are pure drainage problems with a functional membrane. Cleaning drains is the highest-ROI maintenance task on any commercial flat roof in this neighborhood.
If you own or manage a SoMa building and don't have a roofing maintenance contract, get one — ours or someone else's. Visit our SoMa service area page or call 415-770-7600 to schedule a free assessment.