Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
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AfterOwens Corning Roofing in San Francisco, CA | Mercer Roofing
We provide independent Owens Corning roofing service across San Francisco, and the single factor that separates our Owens Corning work here from anywhere else is fog. Not rain. The marine layer saturates western flatland rowhouses for weeks at a stretch, and Owens Corning shingle systems on those roofs fail differently than identical installations ten minutes east. If you need Roof Repair - San Francisco, re-flashing, or full replacement in San Francisco, call Mercer Roofing at (743) 200-8347 for a written estimate.
We’re not an Owens Corning authorized contractor, and we’ll tell you that straight. What we are is a crew that has torn off and re-covered enough Owens Corning Duration, Oakridge, and Supreme fields on zero-lot-line rowhouses to know exactly how their granules, seal strips, and accessory flashings behave in fog-belt conditions. Grant Whitlock, our owner, learned structural roofing fundamentals at Los Angeles Trade-Technical College and has spent nearly two decades reading roofs before touching them. That matters when you’re deciding between a $900 repair and a $14,000 re-roof on a 1910 Edwardian flat in the Inner Richmond.
Call (743) 200-8347 and a live person answers, day or night, not a voicemail tree.
Why San Francisco Residents Choose Us for Owens Corning Service
We work Owens Corning shingle systems alongside GAF and CertainTeed every week, which means we can give you a straight comparison instead of a brand pitch. If an Oakridge field makes sense on your western flatland rowhouse, we’ll say so and quote it. If a CertainTeed Landmark holds up better at the fog edge, we’ll tell you that too. Homeowners in San Francisco choose us because we lead with the badge-at-the-door promise: every technician is background-checked, identity-verified, and their name and photo are sent to you before they arrive. When they knock, they present a photo ID badge in a clean, marked uniform. That’s the Threshold Verified standard, and every Mercer location operates under it.
Every Owens Corning repair we quote in San Francisco comes with a written price before any work starts. No exceptions, no change orders mid-job. And every repair carries a written guarantee for 365 days, with a free second visit if the repair fails. Grant has told more than one Outer Sunset homeowner that a $650 re-flash beats a $12,000 replacement, and he means it. Our job is to give you accurate information, not to sell a roof you don’t need.
Common Owens Corning Roofing Problems We Solve in San Francisco
- Granule loss at the fog edge. Duration and Oakridge shingles on Outer Sunset and Inner Richmond roofs cycle wet-to-UV constantly. The granules wash into gutters years before the same shingle would thin out in the Mission. We diagnose the mat exposure, check the decking underneath, and give you a straight repair-or-replace answer.
- Algae streaking and black moss on north-facing fields. The marine layer keeps shingles damp long enough for gloeocapsa magma to take hold. This is rare on the sunnier east side of the city, but common on Twin Peaks and western flatland slopes. We’ll tell you whether it’s cosmetic or whether the mat underneath has started to rot.
- Seal-strip separation from thermal cycling. Fog-boundary roofs heat and cool unevenly, so field shingles lift and crease during the next wind event. You’ll see this pattern far more in the Parkside and Outer Richmond than in Potrero Hill. We re-seal or replace the lifted courses before water gets under the field.
- Failed flashing at parapet and party-wall terminations. On low-slope and minimally-sloped Owens Corning installations, water backs up under the shingle course at these details long before the shingle itself wears out. This is the number one call we get on Victorian and Edwardian rowhouses. We rebuild the flashings by hand, often without side-yard access.
- Decking rot under the eaves where fog drip concentrates. San Francisco fog doesn’t pour off a roof, it condenses and drips. On attached rowhouses with parapet walls, that drip line saturates the eave decking over years. We find soft spots during every Owens Corning inspection on the west side.
Owens Corning Service in San Francisco: What Local Conditions Mean for Your Equipment
Here’s a checkable fact that shapes how we schedule Owens Corning work in San Francisco: because Karl the Fog parks over the Outer Sunset, Inner Richmond, and Twin Peaks for weeks at a time, a Duration or Oakridge field on a western flatland rowhouse can lose granules and grow moss at roughly double the rate of an identical roof ten minutes east in the Mission or Potrero Hill. That means we set inspection and re-flashing schedules for western-neighborhood Owens Corning roofs by the fog calendar, not the rainfall calendar. The city’s official annual rainfall sits around 20 inches, and that number tells you almost nothing about when your roof is actually failing. A Sunset roof that gets 50 weeks of morning saturation but only 20 inches of rain is wetter than a rainy-climate roof in Ohio that gets 40 inches but dries out between storms. If you own an Owens Corning roof in the fog belt, you need a roofer who knows that difference and doesn’t just look at the weather report.
We saw this play out on a 1912 Edwardian rowhouse in the Inner Richmond. Our tech found an Oakridge field on the front slope with seal strips separated and black algae streaking from ridge to gutter, plus a rotted fascia at the party-wall flashing. We stripped the field, replaced the decking at the eave, set new WeatherLock underlayment and Oakridge shingles, and rebuilt the parapet and party-wall flashings by hand since there was no side-yard access. Every bundle came over the front parapet on a rope and pulley and through the occupied upper flat. That’s the labor nobody sees on the bid, but it’s part of what an accurate San Francisco Owens Corning quote must account for.
Owens Corning Models & Products We Service in San Francisco
We install and repair the full Owens Corning architectural line: Duration Series with TruDefinition color, Oakridge architectural shingles, and the Supreme and ProEdge base shingle lines. We stock WeatherLock self-adhered underlayment and matching accessory flashings locally so we’re not waiting on a distributor truck when your parapet flashing fails on a foggy Tuesday. We install genuine Owens Corning shingles, WeatherLock underlayments, and accessory flashings so your system stays within its intended warranty pathway. Where Owens Corning doesn’t make an equivalent part, we use quality aftermarket vent boots and pipe collars. We’ll tell you which is which on the quote, not after the fact.
As an independent Owens Corning sales & service shop, we don’t have a manufacturer quota to hit. That independence is worth something when the honest recommendation is to repair rather than replace.
Owens Corning Service Pricing in San Francisco
Owens Corning shingle repair in San Francisco typically costs $180 to $340 for a targeted fix. Flashing repair runs $450 to $900 depending on parapet access and party-wall complexity. A full Owens Corning architectural re-roof on a typical San Francisco rowhouse runs $9,000 to $33,000, with the spread driven by decking condition, number of stories, and whether we’re hoisting materials over a front parapet or carrying them through a lived-in interior. If a field is under about a third of the roof and the mat is still intact, we patch and re-flash. Once granules are gone across whole slopes, replacement is the honest call. Your free estimate includes a written line-item breakdown, so you see exactly what the labor, materials, and access constraints cost. Call (743) 200-8347 and we’ll schedule a time to look before you spend a dollar.
Serving San Francisco, CA - Our Local Coverage Area
We’re a Roofing Company - San Francisco based in the 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 – Owens Corning Roofing in San Francisco
Owens Corning Duration shingles hold up as well as any architectural shingle in San Francisco’s fog belt, and we have installed them successfully in the Outer Sunset and Inner Richmond. But no asphalt shingle is immune to the marine layer. The west side’s constant saturation means granules wash, moss grows, and seal strips separate faster than they do on the east side of town, regardless of brand. If you want maximum service life, plan for an inspection and re-flashing every few years based on the fog calendar. Call (743) 200-8347 for an assessment.
Because the Sunset sits under the marine layer for weeks or months at a stretch while the Mission dries out. Moss and algae need sustained damp, and the fog provides it. Your friend’s roof in the Mission gets the same sun and rain but without the constant condensation. That’s a San Francisco-specific pattern, not an Owens Corning defect. We can clean and treat the moss and check whether the mat underneath is still sound. Call (743) 200-8347 for an exact quote.
Yes, and we do it regularly across the Castro, Mission, and Western Addition. Attached rowhouses with zero-lot-line construction have no side access, so our crews hoist every bundle over the front parapet with rope and pulley or carry materials through a customer’s occupied interior. Either way, it adds labor hours that belong on the bid. We quote that line item separately so you never get surprised by it after the fact.
If the seal strips have separated on only part of the field and the mat is still intact, we can often re-seal or replace the affected courses and treat the algae. If granules are gone across whole slopes and we can see mat exposure, replacement is the honest call. The tipping point is usually whether the decking beneath has started to rot from the fog drip. We’ll show you photos of your own roof and give you a written repair quote and a replacement quote side by side, then let you decide. Call (743) 200-8347 for a free estimate.
No. San Francisco’s housing stock is overwhelmingly flat or low-slope built-up and modified bitumen roofs, and we work on those every day. But plenty of rowhouses and stucco homes in the Sunset, Richmond, and beyond carry pitched Owens Corning shingle fields on at least one slope, and we inspect, service, and re-roof those systems with the same care. If you have both a flat membrane roof and a shingle slope on the same house, we can handle both and coordinate the flashing where they meet.
Service Areas Near San Francisco
We serve all of San Francisco, including the Outer Sunset, Inner Richmond, Twin Peaks, the Mission, and Potrero Hill. For Owens Corning work beyond the city, see our San Francisco service area page. We also provide Owens Corning service in Fresno and Owens Corning service in Sacramento for Central Valley homeowners. Every visit carries the same Threshold Verified standard and the same written price before work starts.
Book Your Owens Corning Service in San Francisco Today
Tell us what’s happening on your roof and we’ll send a background-checked, uniformed technician with a photo ID badge and a written quote. Call (743) 200-8347 now. Same-day visits are available when the job warrants it. A roof that’s doing its job is one you never think about. Let’s keep it that way.
Written by Grant Whitlock, Owner at Mercer Roofing, serving San Francisco since 2000.