Metal roofing
Architectural shingles
Tile roofing
GAF
Owens Corning
Flat & low-slopeFree roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Fast, Reliable Roofing Company Across Portola Valley
Roofing work in Portola Valley means working with steep wooded lots, strict hillside codes, and estate homes that deserve more than a generic tear-off and nail job. A full roof replacement here typically runs $22,000 to $65,000 depending on slope, decking condition, and material. Repairs land between $450 and $2,800 for most jobs. We schedule Portola Valley calls with a written price before any work starts, background-checked uniformed technicians, and a live person on the phone when you call (669) 238-2101.
Why Brennan Roofing Co San Jose Is Portola Valley’s Preferred Roofing Company Company
Portola Valley homeowners don’t call around looking for the cheapest bid. They call because a previous roofer no-showed, underbid the job, or cut a corner that the town’s Wildland-Urban Interface inspector caught on reinspection. Travis Oakley runs our crew to a different standard. We put the price on paper before any work starts and it does not move at the door. Every technician is background-checked and shows up in uniform, inside the promised window. And every job carries the 365-Day Done Right Promise: one full year, in writing, with a free return visit if anything fails.
We dispatch crews to Portola Valley from our local scheduling team, with materials sourced from GAF, CertainTeed, and Tamko. You’ll know exactly who is on your roof and exactly what they’re installing, down to the underlayment spec. That specificity matters in a town where the WUI inspector will open the permit file and verify it.
Styles & brands we work with






Commercial Roofing in Portola Valley
Commercial roofing in Portola Valley generally means low-slope or flat sections on estate properties, detached garages, pool houses, or local ranch buildings where the roof geometry is wider than it is steep. The job involves tear-off to decking, replacing damaged insulation board or OSB, laying down a self-adhered base sheet, and finishing with a TPO or modified bitumen membrane. Most Portola Valley commercial flat roof replacements run $18,000 to $45,000, with the biggest cost driver being how much decking has failed once the old surface comes off.
Flat Roof Transitions on Estate Properties
Many Portola Valley homes combine steep gable sections with flat-roofed wings. The transition is where we find trouble. Old torch-down joins a shingle slope with nothing but a strip of failing metal, and the first heavy winter rain pushes water sideways under both systems. We rebuild that transition with a proper cant strip, double-layer membrane, and drip edge that drains away from the structure, not behind the fascia.
WUI Compliance for Accessory Structures
A detached garage or pool house in Portola Valley still has to pass the same Class A fire-rating inspection as the main house. We bid commercial flat work here with a Class A assembly from the deck up, because the inspector checks accessory structures just as closely as primary roofs.
Metal Roof Installation in Portola Valley
Metal roof installation in Portola Valley has become the default answer for homeowners who want to stop re-roofing every fifteen years and stop fighting the WUI fire-rating battle with every permit. Standing seam panels carry a Class A fire rating from the factory, shed pine needles and leaf litter that accumulate on wooded lots, and handle the low-pitch and complex geometry common to hillside estates. Typical standing seam metal roof replacement in Portola Valley runs $35,000 to $75,000 on larger custom homes.
Standing Seam on Custom Geometries
Portola Valley roofs don’t come in simple rectangles. Multiple gables, shed dormers, crickets, and curved eyebrow sections mean the panel layout has to be drawn panel by panel. We field-measure every plane and send fabrication drawings that account for valley transitions and eave lines nobody sees from the street. That discipline keeps water out and keeps the inspector moving.
Metal Over an Existing Wood Shake Roof
Some homeowners ask about framing over an older wood shake roof instead of a full tear-off. We don’t recommend it. You’d trap dry shake under metal, and the WUI inspector will flag the assembly. The right call is pull the shake, inspect the decking, and start clean. That’s how we bid it, and the price reflects it on paper from day one.
Trusted Brands We Service in Portola Valley
We install and stand behind roofs built from GAF, CertainTeed, Boral, and Tamko lines. For Portola Valley’s WUI-driven reroofs, that usually means CertainTeed Landmark architectural shingles or a GAF Timberline line, paired with StormGuard or an equivalent self-adhered ice and water shield at the eaves and valleys. We also do standing seam metal systems and offer ceramic or concrete tile from Boral where the original design calls for it. Parts and matching components are stocked nearby, so warranty follow-up and repair turnarounds in Portola Valley are measured in days, not weeks.
See the difference
Before
After
Before
After
Before
AfterCommon Roofing Company Problems We See in Portola Valley Homes
- Original 1/2″ CDX decking rotting at valleys and transitions. Homes from the 1960s through the 1980s were often built with thin decking that cannot hold a modern nail pattern once it starts to soften. A tear-off almost always turns up replacement squares, and a quote without that allowance is a quote that will change.
- Wood shake roofs that cannot pass a WUI reinspection. Maintaining an existing shake roof is possible until it needs significant repair, then the town requires a Class A assembly. That means tear-off, new underlayment, and either Class A composition shingles or standing seam metal.
- Missing ice and water shield on low-pitch sections. Low-slope roofs in Portola Valley are common on mid-century and 1970s custom homes. The original builders often skipped self-adhered membrane at the eaves and valleys, and the first heavy winter rain after a re-shingle finds the leak.
- Reused galvanized drip edge hiding soffit-to-fascia failure. Old drip edge often survived the original roof but wasn’t replaced at the last reroof. Water follows it into the fascia, and years later the trayce starts swelling. A proper reroof replaces drip edge and inspects the soffit transition in the same pass.
Pricing for Roofing Company in Portola Valley, CA
A typical full roof replacement in Portola Valley runs $22,000 to $65,000, with higher-cost projects tied to steep pitches, extensive decking replacement, and metal or tile material choices. Roof repairs generally run $450 to $2,800. The single biggest variable on older homes is decking: opening a 1970s estate often reveals 5 to 15 squares of OSB or CDX that need replacing before the new underlayment goes down. Inspection of the decking condition happens during our first visit, with a written line-item estimate that includes a decking replacement allowance. That number is in your hand before any work starts. Call (669) 238-2101 to schedule a free estimate for your Portola Valley roof.
We Also Serve Cities Near Portola Valley
Our Roofing Company crews regularly work the hillside and estate communities around Portola Valley. We serve Stanford, Los Altos, Atherton, and Palo Alto with the same written-pricing standard and Class A fire-rated assemblies. If you’re in one of those neighboring communities, Portola Valley homeowners can tell you what to expect from the Garrison Standard on a local job.
Serving Portola Valley, CA - Our Local Coverage Area
We’re based in the Portola Valley area and know this community well. Use the map below to see our service coverage - if you’re nearby, we can almost certainly help.
FAQs About Roofing Company in Portola Valley
Yes. Portola Valley enforces Wildland-Urban Interface building standards, and any roof tear-off and replacement on a hillside or wooded lot requires a permit that includes a WUI inspection. The inspector verifies that the assembly carries a Class A fire rating, which means approved underlayment, ridge vents to WUI spec, and noncombustible drip edge at all exposed edges. Call (669) 238-2101 and we’ll explain how your existing roof maps to the current checklist before you commit to a bid.
You can maintain an intact shake roof with repairs, but any significant replacement on a WUI-regulated property will require a Class A assembly instead of new wood shake. That shift is why most Portola Valley homeowners now move to standing seam metal or Class A composition shingles. The inspection point is the trigger, and we price the whole transition in writing so there’s no gap between what the town requires and what your bid covers.
On older Portola Valley homes, expect 5 to 15 squares of decking replacement once the old roof comes off, with higher numbers where original CDX has rotted at valleys, eaves, or flat-roof transitions. Our written estimate includes a decking allowance based on the roofing section that’s visible during inspection, and we price any additional decking in writing before we install it. That way the reroof price on paper is the price you pay.
Standing seam metal carries a Class A fire rating from the factory, performs better on the low pitches common in Portola Valley estate design, and sheds the pine needles and leaf litter that accumulate on homes up on Westridge Drive or along Alpine Road. It also ends the WUI compliance argument at the counter. Metal costs more than Class A composition shingles, so we lay out both options and their installed prices before you choose.
A flat roof section can meet Class A compliance, but only if the membrane assembly is installed with a self-adhered base, Class A rated cap sheet or coating, and proper edge metal at the parapet and fascia. Homes with older torch-down flat sections often fail inspection because the transition to the shingle slope lacks a proper cant strip and drip edge. We address both the flat section and the transition in the same bid.
Written by Travis Oakley, Owner at Brennan Roofing Co San Jose, serving Portola Valley and surrounding hillside communities.