Roof systems · Metal
Commercial Metal Roof Repair: Fastener Leaks, Seams and Coatings
For warehouses, industrial and ag buildings with metal roofs dripping at the screws, laps or skylights.
- Free roof condition report: repair, coat or replace?
- Good, better and best options
- Certificate of insurance within 24 hours of request
Types of commercial metal roofs
- Exposed-fastener panels: screws with sealing washers go through the panel, and water sheds over overlapping laps.
- Standing seam: concealed clips hold the panels, and raised seams keep water away from the joints.
You'll find metal roofs on warehouses, industrial and ag buildings and pre-engineered buildings, in Watsonville and other Santa Cruz County and South Bay industrial areas. Gutters, coping and flashing on any roof are covered on sheet metal, flashing and drainage.
Illustrative image, not a completed project.
Why metal roofs leak
Fasteners
Sealing washers age and crack in sun and temperature swings, screws back out as panels move, and over-driven or misaligned screws never sealed.
Side and end laps
Sealant at panel overlaps drying out.
Skylights and curbs
Flashing and fasteners around openings.
Ridge and eave closures
Gaps that let in wind-driven rain.
Rust
At cut edges and laps, faster near the coast.
Repair, coat or replace a metal roof?
| Option | Usually fits when |
|---|---|
| Repair | Leaks trace to fasteners, laps or skylights: replace or oversize failed fasteners, reseal laps and skylights, and treat rust spots. |
| Coat | The panels are structurally sound. Fasteners and seams are treated first, rust is cleaned and primed, and the coating system is listed for metal. Chemistry: roof coating systems. |
| Replace or retrofit | Rust-through or panel damage is widespread. |
A roof condition report tells you which you have.
Metal roofs and Title 24
- Unconditioned buildings, which includes many warehouses, don't trigger the cool-roof rules (CEC 2025 Nonresidential Cool Roofs FAQ).
- Conditioned, low-slope (under 2:12): re-roofs or recoats over more than 50% of the roof area or more than 2,000 square feet, whichever is less (Energy Code §141.0(b)2B) need aged solar reflectance of at least 0.63 and thermal emittance of at least 0.75, or an SRI of at least 75, with a CRRC label (§140.3(a)1A). Our Title 24 re-roof guide walks through the trigger, the cool roof values and the insulation rule.
- Conditioned, steep-slope (2:12 or steeper): alterations must meet the same steep-slope values as new construction. Climate zones 1 and 3: aged solar reflectance of at least 0.20 and thermal emittance of at least 0.75, or SRI 16. Zones 2 and 4–16: at least 0.25 and 0.80, or SRI 23. A barrel roof counts as steep-sloped (CEC FAQ; §140.3(a)1A).
Bare, unpainted metal often has low thermal emittance, so check the product's CRRC listing.
Retrofit options over metal
A structurally sound metal roof can be coated, or recovered with a single-ply membrane such as TPO over the panels. Which fits depends on the panel profile, the building's use and whether the cool-roof rules apply.
Where we work
Commercial, industrial, multifamily and HOA roofing across six Bay Area counties.
- Santa Clara County, CASan Jose, Santa Clara, Sunnyvale, Mountain View, Palo Alto, Milpitas
- San Francisco County, CASan Francisco
- San Mateo County, CARedwood City, San Mateo, South San Francisco, Burlingame, Foster City
- Alameda County, CAOakland, Fremont, Hayward, Newark, Pleasanton, Berkeley
Frequently Asked Questions
Usually the sealing washers. On exposed-fastener metal roofs, rubber washers age and crack in sun and temperature swings, and panel movement can back screws out. Some were over-driven or misaligned when installed. Replacing or oversizing the fasteners and resealing the laps usually stops the leaks.
Yes, if the panels are structurally sound. Fasteners, seams and laps are treated first, rust is cleaned and primed, and the coating must be listed for metal. On a conditioned building above the size threshold, the coating has to be a CRRC-rated cool roof product.
Not if the building is unconditioned. For conditioned buildings, re-roofs covering more than half the roof or more than 2,000 square feet, whichever is less, must meet cool-roof values. Steep-slope metal roofs (2:12 or steeper) in climate zone 3 need aged reflectance of at least 0.20 and emittance 0.75, or SRI 16.
Find where water gets in: the skylight curb flashing, the laps around it or the skylight itself. Most leaks are at the flashing and fasteners around the opening, which can be resealed or re-flashed. Cracked or brittle skylight panels should be replaced, with fall protection in place while the opening is exposed.
It speeds up corrosion, especially at cut edges, laps and fasteners. Coastal metal roofs in Santa Cruz County and along the Bay benefit from regular checks, prompt rust treatment and compatible fasteners.
Let's get started
Request a metal roof repair bid
Tell us the property, the building type and where it's leaking. For an active leak, call.
- (408) 770-5992Calling is fastest for an active leak