Clips, Thermal Movement and Oil Canning
Metal grows and shrinks with temperature. On a hot afternoon, with Pasadena's recorded high of 113 F in June, a long panel expands noticeably along its length and contracts again overnight. Floating clips let the panel slide, and fixed clips hold it near the middle, so a roof is designed to move without stress at any one point. A panel pinned by a screw through its face, or a trim piece fastened across its path, will crack its seam or tear its own fastener hole.
Oil canning is the visible waviness that shows on flat metal in raking light. It is cosmetic, but owners notice it, and we reduce it with a heavier gauge, stiffening ribs and careful installation over a flat deck. Fit and finish at the ridge and eave count as much as the field panel. A roof with clean, even reveals and tight corners reads as well built from the street, and its trim works as well as it looks.
Wind Uplift at Eaves and Ridges
Wind pulls hardest at edges, corners and ridges, which is where uplift pressures are highest and where clip spacing and edge trim take the load. Before the Eaton Fire, forecasters expected Santa Ana gusts between 60 and 80 mph over a wide area and a few stronger ones, and a roof in Altadena, Sierra Madre or the upper foothills carries that exposure. Even Jet Propulsion Laboratory, which closed and evacuated during the fire, reported minor wind damage, so wind alone is enough to test a roof edge.
We build the perimeter to the uplift pressures the code calls for under ASCE, using closer clips near edges, continuous cleats under the trim and hemmed metal that cannot peel away from the fascia, the same standard we apply to edge metal and gutters on other roofs. When a storm strips trim or lifts a panel, a wind damage roof repair restores the edge before more water finds the gap.
Noncombustible Panels in Fire Zones
Metal panels do not burn, but the rating that matters belongs to the entire assembly. California Chapter 7A requires the Class A rating to be achieved by the deck, underlayment and covering together, and Pasadena's March 2025 state map raised properties in the Very High zone from 3,911 to 4,610. Embers do their damage at openings: an open ridge, a loose eave, a vent without a screen. Metal profile closures at the ridge and eave, ember-resistant vents and gutter debris protection close those paths.
We confirm the full assembly before specifying panels in the Arroyo Seco and upper Hastings Ranch, where mapped fire zones lie. The underlayment under the panel does real work, since a metal roof lets heat through, and a tested underlayment keeps the deck from becoming the weak link. We record what was installed with photographs and a roof plan, so a plans examiner or an insurer has the whole assembly in front of them.
Rebuilding in Altadena and Care Over Time
The Eaton Fire damaged Altadena's downtown business district, destroying shops and service businesses, and a rebuilt shop or office there can choose metal for its noncombustible surface and long service life. A new standing seam roof over a rebuilt shop or office needs its curbs, trim and penetrations laid out before the panels are ordered, and the order of work keeps the detail intact.
Metal needs a modest routine. We check clips, sealant joints and fastener heads on trim, clear leaves from valleys and gutters, and look for scratches that expose bare steel. Coatings chalk and fade over time, and a worn finish may be recoated with a compatible system, such as a silicone roof coating. Dissimilar metals deserve a watchful eye, since copper next to steel will corrode the steel wherever water carries it.
Commercial Roofing Questions
Do standing seam roofs leak more at penetrations than other roofs?
They leak at penetrations when the flashing is generic, and not when it is fabricated for the opening. A curb with an upslope cricket, side pans and a lapped apron stays dry, while a bead of sealant around a pipe does not. We fabricate the metal for each opening, which is why the openings are where we spend the most time.
Why do my metal roof panels tick and pop in the afternoon?
The panels are expanding in the heat and sliding on their clips, and a ticking sound is the metal moving across a trim edge or a clip that is binding. It is often harmless, though a loud pop can mean a clip is fixed where it should float. We check the clip layout and the trim fasteners, and adjust whichever is blocking the panel's movement.
Is standing seam metal a Class A roof in a Fire Hazard Severity Zone?
Noncombustible metal still needs a tested assembly, because the rating comes from the deck, underlayment and covering together. We specify an assembly that has a Class A listing, add ember-resistant vents and metal closures at the ridge and eave, and keep the paperwork for the permit and the insurer.
Can standing seam go over an existing low-slope roof?
Often, using a framing system that lifts the new roof above the old one, but the structure must carry the added load and the old roof must be dry beneath. An infrared survey and a structural check come first. A metal roof retrofit over an old exposed-fastener panel works the same way.
What fades or fails first on a coated metal roof?
The factory coating chalks and fades first, followed by the sealant at trim and penetrations, then fasteners on any exposed trim. Panels rarely fail in the field. We inspect the sealed joints and clips on a schedule and recoat the finish when it has worn, so the metal beneath is never left bare.
