Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Before
After
Before
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Before
AfterFast, Reliable Roof Repair Across San Lorenzo
Roof repair in San Lorenzo usually means one thing: a 70-year-old Bohannon-era home with decking that’s quietly failing under layers of old shingles. Most repairs we do here run between $450 and $1,800 depending on what’s hidden underneath, and we’ll give you a written price before we touch anything. If you’ve got a leak, missing shingles, or soft spots you can feel when you walk the roof, call us at (424) 766-4937. We know these homes because we work on them every week.
What makes San Lorenzo different is simple: nearly every house went up between 1945 and 1955, so we see the same aging patterns again and again. The original skip-board sheathing, the low-pitched gable roofs, the moisture that settles in from the bay. We know what’s under your shingles before we even climb the ladder.
Why Birchbark Roofing Is San Lorenzo’s Preferred Roof Repair Company
Local reputation matters when the crew is walking through your hallway to get to the attic hatch. Our technicians are background-checked and uniformed, and they put shoe covers on at the door and drop cloths through the hallway before anyone sets foot inside. That’s a specific protection, not a slogan.
Erik Lindgren, our owner, built Birchbark around one question: what would a careful roofer do at his own house? The answer became the C.A.R.E. values. Clean up like it’s our own home. Ask before we move or touch anything. Respect the family’s time and quiet hours. Explain the price before the work. Every job in San Lorenzo runs on that standard.
Response time to San Lorenzo is same-day or next-day for emergency leak calls. A live person answers the phone 24 hours a day, seven days a week. No voicemail tree, no “we’ll call you back Monday.” When water is coming through your ceiling on a Sunday, you talk to a person on Sunday.
Every repair carries our 365-Day Done Right Promise: if it’s not done right, we make it right. No fine print, no re-inspection fees. And every job ends with a photo of the completed clean-up before the crew leaves. You’ll see your yard and walkways the way we found them.
Commercial Roof Repair in San Lorenzo
Commercial Roof Repair in San Lorenzo covers the flat and low-slope buildings along Hesperian Boulevard, Lewelling Boulevard, and the industrial pockets near the Union Pacific tracks. Most commercial jobs here involve built-up roofing, modified bitumen, or TPO membranes that have developed blisters, splits, or ponding water that works its way into the insulation and decking below.
Commercial repairs in San Lorenzo typically run $800 to $3,500 depending on the membrane type and the size of the repair area. We start with a core sample and a moisture scan to find the actual source of the leak rather than chasing a stain on the ceiling tile. That saves you money because we fix the real problem once instead of re-coating a membrane every eighteen months.
Flat Roof Patch and Membrane Work
A proper flat roof patch here means cutting back to dry, bonded material, priming the splice, and heat-welding or cold-applying a new section that overlaps the existing membrane correctly. Done wrong, a patch just moves the leak six inches. We use manufacturer-specified products from GAF and CertainTeed rated for bay-area moisture and UV exposure.
Parapet and Flashing Details
The most common commercial failure point in San Lorenzo is where the roof meets the parapet wall. The original counterflashing and termination bar fail, wind-driven rain gets underneath, and the water travels sideways for twenty feet before it shows up as a stain inside. We strip the failing detail back to sound decking and rebuild it with new termination bar, sealant, and a proper cover flashing. If the scupper drains are clogged with leaf debris from the mature street trees, we clear them and add screens.
Roof Leak Repair in San Lorenzo
Roof Leak Repair in San Lorenzo starts with finding the actual point of entry, not the spot where the paint is bubbling on your ceiling. Water travels sideways along rafters and sheathing, especially on the low-pitched gable roofs that dominate the Bohannon tracts east of Hesperian and west of I-880.
We use hose testing, attic inspection, and sometimes an infrared moisture meter to trace the path. Most leak repairs in San Lorenzo run $350 to $900 for a single penetration or flashing detail. If the decking underneath has rotted, plan on $1,200 to $2,400 to open the roof, replace the boards, and re-shingle the area correctly.
Vent Boot and Flashing Replacement
Vent boots dry out and crack after 10 to 15 years in bay-area sun and fog cycling. We replace them with new lead or engineered rubber boots, sealing the underside with proper flashing cement and mechanically fastening the base before re-bedding shingles. A valley repair near Bockman Road or Via Arroyo involves stripping the valley, inspecting the metal, and often replacing a rusted-through section with new 28-gauge galvanized or painted steel.
Shingle and Soffit Repair
Marine-layer fog keeps the north and west roof planes damp well into the late morning, which means granule loss and moss growth happen faster here than in Castro Valley or other inland spots. We replace curled, cracked, or missing shingles with a brand match where possible, and we check the soffit and fascia for dry rot while we’re on the ladder. If the dog is in the yard, we coordinate the door schedule with you before anyone starts.
Trusted Brands We Service in San Lorenzo
We work with materials from GAF, CertainTeed, and Owens Corning, and we keep common stock in the truck for San Lorenzo jobs. That means a shingle match, vent boot, roll of valley metal, or tube of roofing cement usually arrives with the crew on the first visit, not a week later after a special order. If your original roof was CertainTeed, we’ll try to match it. If it’s an older GAF Timberline, we’ll know which color code to reference. For commercial flat roofs, we carry GAF TPO and CertainTeed Flintlastic accessories locally. Birchbark is part of the Cedarwell family of independent roofing businesses, which gives us access to supplier pricing and material availability that a solo operator doesn’t have. You’ll see the brand and the price written on your estimate before any work begins.
Common Roof Repair Problems We See in San Lorenzo Homes
- Hidden dry rot in original sheathing: The 1945-1955 Bohannon homes were built with diagonal or skip-board sheathing, and after 70-plus years of bay moisture, those boards often bounce when stepped on. A simple shingle patch sometimes becomes a decking replacement once the roof is opened, and we always write that allowance into the contract so you’re not surprised.
- Moss and granule loss on north and west roof planes: The marine layer lingers here longer than in hillside communities, so the shadier sides of your roof stay damp and grow moss faster. Moss holds water against the shingle surface, which accelerates granule loss and shortens the effective life of the roof, especially on homes near San Lorenzo Creek where the air is even wetter.
- Multiple re-roof layers trapping moisture: Many of these homes have one or two layers of newer shingles over the original roof. Without a tear-off between installations, moisture gets trapped between layers and rots the decking from the top down. We’ve pulled shingles near the San Lorenzo Community Center and found the original 1951 boards soft enough to push a finger through.
- Failed flashing at chimneys and pipes: The mortar and flashing around brick chimneys on the original homes breaks down over time, and the pipe collars leak slowly for years before anyone notices. By the time the ceiling stain appears, the decking underneath is usually already compromised, which is why we recommend an attic inspection at the first sign of discoloration.
Pricing for Roof Repair in San Lorenzo, CA
Here’s what you can expect to pay for common repairs in San Lorenzo: shingle replacement runs $350 to $700 per section, vent boot replacement $250 to $450, flashing repair $400 to $900, valley repair $500 to $1,200, flat roof patches $600 to $2,000, and decking replacement with re-shingle $1,200 to $2,400 per section. The single biggest variable is what we find when we open the roof, which is why we write an allowance into every contract for concealed decking damage. You’ll see the exact number in writing before we start, and no change order ever gets approved without your signature. Call (424) 766-4937 for a free estimate. We’ll walk the roof, take photos, and give you a fixed line-item price.
We Also Serve Cities Near San Lorenzo
Our Roof Repair crews cover the whole East Bay lowlands. In addition to San Lorenzo, we regularly work in Castro Valley, San Leandro, Union City, and Oakland. The housing stock changes a little from one city to the next, but the bay moisture and the aging construction don’t. If you’re just over the border, we can usually be there the same day.
Serving San Lorenzo, CA - Our Local Coverage Area
We’re based in the San Lorenzo 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 San Lorenzo
Yes, even a patch job requires a permit through the Alameda County Building Department, because San Lorenzo is unincorporated and has no city hall. Our team files county permits as a standard part of the job, which keeps your repair legal and prevents issues when you sell the house later. The county process adds a day or two to the schedule, but we build that into the timeline and handle the paperwork so you don’t have to. Call (424) 766-4937 if you want to know what a specific permit costs for your situation.
The most common reason is that the previous repair addressed the visible shingle damage but not the hidden decking or flashing that was actually letting water in. On Bohannon-era homes with original skip-board sheathing, water travels sideways along the boards and exits far from the entry point, so the repair missed the real source. Also, the marine fog keeps north-facing planes wet for months, so any small gap in flashing gets a long season to leak. We find and fix the entry point, not the stain on the ceiling. For an exact diagnosis, call (424) 766-4937 and we’ll walk the roof with you.
The clearest signs are soft spots or bounce when you walk the roof, visible sag between rafters when you look from the attic, and dark staining or granule loss concentrated in one area. If you see daylight through the attic boards or the shingles look wavy from the ground, the decking underneath has likely been absorbing moisture for years. We inspect the attic space and use a moisture meter during every repair estimate, then we photograph what we find. The written quote will show exactly which boards need replacing and what it costs.
We work with GAF, CertainTeed, and Owens Corning shingles, so we can usually match the original color and profile on your roof. For a full section replacement, we’ll quote the brand that best matches your existing roof, and we’ll note the brand name and color code on your written estimate before the work starts. If you prefer a certain manufacturer after seeing the options, we’re happy to price it both ways. The 365-Day Done Right Promise applies regardless of which brand you choose.
Yes, we repair commercial flat roofs throughout San Lorenzo, including the retail and industrial properties along Hesperian and Lewelling Boulevards. That includes leak investigation, membrane patching, parapet flashing rebuilds, scupper clearing, and small coating applications. Most commercial repairs run $800 to $3,500, and we’ll give you a written price with a moisture survey before any work begins. Call (424) 766-4937 to schedule a site visit.
Written by Erik Lindgren, Owner at Birchbark Roofing, serving San Lorenzo and the surrounding East Bay communities.
If your roof is leaking or you suspect decking damage, call Birchbark Roofing at (424) 766-4937 for a free estimate. We’ll walk the roof with you, show you photos of what we find, and give you a written line-item price before any work starts. Shoe covers at the door, drop cloths through the hallway, a clean-up photo before we leave, and the 365-Day Done Right Promise on every job.