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Architectural shingles
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Flat & low-slopeFree roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Fast, Reliable Roof Repair Across Portola Valley
Roof repair in Portola Valley costs $450 – $2,400 for most jobs, with leak repairs typically running $350 – $900 and larger structural fixes reaching $6,000+. The number moves based on what’s actually under the shingles, and in Portola Valley, that matters more than most places. We serve the town’s hillside estates, wooded lots, and custom homes with crews who understand Wildland-Urban Interface codes and the specific ways these roofs fail. Call (669) 238-2101 for a written estimate before any work starts.
Portola Valley homes aren’t like the tract housing down in the valley. Steep hillsides, oak canopies, low-pitch sections, aging custom framing. A leak here isn’t just a leak, it’s the first sign of a bigger conversation about fire-rated materials, rotted decking, and what the town’s building department will require once you pull a permit. We know that conversation because we have it with homeowners from Westridge to Los Trancos Woods every week.
Why Brennan Roofing Co San Jose Is Portola Valley’s Preferred Roof Repair Company
We operate under The Garrison Standard. Written price before any work starts. Background-checked, uniformed technicians who show up inside the promised window. A full year written guarantee on every repair. That’s not marketing language; it’s the operating code every Brennan Roofing crew works under, and Travis Oakley holds the line on it.
Portola Valley homeowners have dealt with roofers who quote one number and show up with another, or who never call back at all. Our phones are answered by a live person around the clock. No voicemail, no callback queue. When you call about a leak off Alpine Road or a failed valley on a Golden Oak Drive estate, you get a human being and a straight answer about when we can be there.
We show up knowing the local terrain. That means understanding that a 1978 custom home with original wood shake isn’t getting a simple patch, it’s getting a Class A material upgrade because the town requires it. It means knowing that leaf litter on low-pitch sections holds moisture and rots decking faster than anyone expects. Roof Repair here is a specialty, not a commodity.
Founded in 2000 as part of the Garrison Partners family, Brennan Roofing is independently owned and operated. Every job gets the same standard: the price goes on paper before any work begins, and if it’s not done right, we come back free within the guarantee period.
Styles & brands we work with






Emergency Roof Repair in Portola Valley
Emergency Roof Repair in Portola Valley usually follows a heavy winter rain event or a windstorm that tears a section of roofing loose on a hillside exposure. When water is coming through the ceiling, the first step is stopping the intrusion, which means tarping, sealing around the penetration, or removing compromised material under controlled conditions. Most emergency roof repairs in Portola Valley run $600 – $1,800 depending on scope and how much material has to come off to find the source. Call (669) 238-2101 and a live person will answer, day or night.
Storm Damage Response
Wind-driven rain hits Portola Valley’s west-facing slopes hard from December through March. We respond with a temporary seal or tarp, then schedule a full repair once conditions allow. The temporary work is priced separately and in writing before anyone climbs up.
Leak Containment
A failed skylight or vent boot can pour water into a bedroom within minutes during a hard rain. We locate the exact entry point, contain it, and quote the permanent fix on paper before pulling materials from the truck. No open-ended work. No surprise charges at the door.
Flat Roof Repair in Portola Valley
Flat Roof Repair in Portola Valley is common on the mid-century and custom modern homes built from the 1960s onward, many of which used low-slope or true flat sections for architectural effect. These roofs collect water, leaves, and debris far longer than pitched roofs, and that standing moisture is what rots the substrate and splits the membrane. Flat roof repairs here typically run $700 – $2,200, with more extensive membrane replacement going higher. We’ll put the number in writing before anything starts.
Ponding and Membrane Failure
Flat and low-slope sections on Portola Valley homes often pond water after heavy rain because original drainage was undersized. That water finds every seam, every lap, every penetration. We repair the compromised membrane and, where needed, re-grade the surface or add tapered insulation to move water off the roof instead of letting it sit.
Low-Pitch Decking Rot
Decades of oak leaves sitting on a low-pitch roof create a damp, shaded microclimate that rots decking from the top down. When we open up a flat section, we commonly find sheathing that looks fine from below but crumbles under a hammer. That’s not a surprise we spring on you later; we inspect first and price the full scope up front.
Trusted Brands We Service in Portola Valley
We install and repair materials from GAF, CertainTeed, Owens Corning, IKO, Atlas, Tamko, and Boral. For Portola Valley specifically, most of our repair work lands on GAF and CertainTeed composition shingles, with Atlas and Boral showing up on the fire-rated tile and composite replacement side. We carry standard repair stock for these lines so a shingle replacement or flashing repair doesn’t wait on a special order. If your existing roof is a discontinued product, we’ll source a visual and performance match or walk you through the upgrade path the town requires.
See the difference
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AfterCommon Roof Repair Problems We See in Portola Valley Homes
- Rotted decking under wood shake and tile: Original 1960s – 1980s roofs often have 1×6 decking with no solid sheathing beneath. Decades of moisture on shaded, low-pitch sections turn that material into sponge. We strip to bare deck, replace what’s rotted, and rebuild with current materials.
- Failed flashing at skylights and chimneys: Complex roof geometries mean more transitions, and every transition is a leak waiting to happen. Skylight curbs, chimney crickets, and valley intersections are where we find most water entry during heavy winter rain events.
- Non-compliant materials on existing roofs: Wood shake roofs that predate current WUI codes can’t be patched with like materials. The town requires Class A fire-rated products on any repair that disturbs roofing. We handle the code path and the paperwork.
- Debris accumulation on low-pitch and flat sections: Oak canopies drop a lot of material. On low-slope roofs, that debris holds moisture and accelerates decking rot and membrane failure. Regular inspection and clearing is the cheapest insurance a Portola Valley homeowner can buy.
Pricing for Roof Repair in Portola Valley, CA
Here are real numbers for the Portola Valley market. Minor shingle replacement runs $350 – $700. Leak repair with some decking replacement runs $600 – $1,200. Flashing repair at skylights or chimney crickets runs $450 – $1,100. Flat roof patch work runs $700 – $2,200. Full valley replacement on a large hillside roof runs $1,500 – $4,500. Anything that triggers rotted decking replacement or a WUI material upgrade moves toward the higher end. The price goes on paper before any work begins, and that number does not move at the door. Call (669) 238-2101 for a free estimate on your specific roof.
We Also Serve Cities Near Portola Valley
Brennan Roofing handles roof repair across the Peninsula, including Stanford, Los Altos, Atherton, and Palo Alto. Each town has its own code quirks and housing stock, and we tailor every repair to the local requirements. Roof Repair in Portola Valley is our focus on this page, but the same Garrison Standard applies wherever our crews go.
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 Roof Repair in Portola Valley
Yes. Portola Valley requires all roof repairs that disturb roofing material to comply with Wildland-Urban Interface standards, which means Class A fire-rated materials. Even a small shingle patch can require the same material standard as a full reroof. We handle the inspection path and paperwork for you. Call (669) 238-2101 and we’ll walk you through what your specific repair triggers before any work starts.
No, not in Portola Valley. Current WUI codes do not allow wood shake repairs; any section you touch must be upgraded to a Class A fire-rated material like composition shingles or metal. We can match the look where possible, but wood shake is not coming back on a permitted repair. The written estimate will reflect the required material upgrade, so there’s no surprise mid-job.
Low-pitch and flat roofs in Portola Valley leak most often because water ponds on the surface and finds its way through aging membranes, failed seams, or deteriorated flashing at penetrations. Leaf litter from the oak canopy makes it worse by holding moisture against the roof surface for weeks. The fix is usually membrane repair plus improved drainage. For an exact diagnosis and a written price, call (669) 238-2101.
We strip the affected section to bare deck, remove the rotted material, and replace it with new CDX plywood or OSB rated for the span. Then we install synthetic underlayment and rebuild the roof assembly to current code before resetting or replacing the tile. This is not a change order we spring on you; we inspect first and write the full scope into the estimate before work begins. Call (669) 238-2101 for a free assessment.
Skylight curbs, chimney crickets, valley intersections, and step flashing where upper roof planes meet lower walls are the critical details. Wind-driven rain on hillside exposures pushes water up and under flashing that would work fine on a flat lot. We check and repair all of these points as part of any repair on a multi-level roof. Call (669) 238-2101 to schedule an inspection.
On a custom 1970s estate off Golden Oak Drive, we found original wood shake over 1×6 decking with no ice and water shield at the valleys. Our crew stripped to bare deck, replaced rotted sections, installed a full synthetic underlayment with ice and water shield at all eaves and valleys, then set Class A composition shingles with new drip edge and ridge vent. All of it passed the town’s WUI inspection on the first visit. That’s what a disciplined repair looks like in Portola Valley, and it’s the only way we work.
When you’re ready to price the job, call (669) 238-2101. A live person answers. We’ll schedule a time, inspect the roof, and put the number on paper before any work begins. Free estimates, written quotes, and a full year of guarantee in writing on every repair.
Written by Travis Oakley, Owner at Brennan Roofing Co San Jose, serving Portola Valley under The Garrison Standard.