Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
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AfterFast, Reliable Roofing Company Across San Francisco
Mercer Roofing handles roof repair, replacement, and maintenance across San Francisco, from the fog-heavy Outer Sunset to the sunnier Mission. A typical roof repair in San Francisco runs $450 – $1,200, while a full re-roof on a flat modified bitumen or built-up roof generally lands between $12,000 and $28,000 depending on square footage, decking condition, and access. We know the Avenues’ chronic marine layer, the Castro’s zero-lot-line rowhouses, and the permit realities of working dense blocks. Call (743) 200-8347 for a written estimate before any work starts, every time.
Why Mercer Roofing Is San Francisco’s Preferred Roofing Company Company
San Francisco homeowners don’t have the patience for vague bids or strangers at the door without identification. Our Roofing Company crews work differently. Before any technician arrives at your home in the Richmond, Noe Valley, or Bernal Heights, you receive their name and photo ahead of the visit. They badge in with a photo ID at your door, wearing a clean, marked uniform. That’s the Threshold Verified standard we’re held to on every single job, no exceptions.
Grant Whitlock leads Mercer Roofing with one operating rule: written price before work starts, written guarantee on every repair, and no surprises on the invoice. Our 365-Day Done Right Promise backs every job. If a repair we make doesn’t hold within a year, we come back and make it right at no charge, and every repair includes a free second visit if it fails. That’s not marketing language. It’s in writing.
We answer the phone with a live person, 24/7, because San Francisco Roof Repair problems don’t wait for business hours. Fog-driven moisture wicks into membranes overnight. A call at midnight from a homeowner in the Sunset with water staining a ceiling gets a real human response, not a voicemail.
Residential Roofing in San Francisco
Residential Roofing in San Francisco almost always means flat or low-slope work on Victorians, Edwardians, and 1920s stucco homes, not the pitched shingle roofs you see in the suburbs. Most homes here carry built-up roofing (BUR) or modified bitumen membranes over straight-sheathed redwood or fir decking. A re-roof on a typical 1,200-square-foot San Francisco flat roof runs $12,000 – $28,000, with the higher end reflecting parapet rebuilds, rotted decking replacement, or especially difficult hoist access on attached rowhouses where there’s no side yard. We spec membrane systems, including Owens Corning service in San Francisco, that handle fog saturation, not storm loading, because that’s what actually fails here.
Flat and Low-Slope Membrane Work
We tear off old BUR or mod bit down to sound decking, then lay new underlayment and membrane with proper taper for drainage. Interior drains and scuppers get reset so water moves off the roof instead of ponding. On zero-lot-line homes in the Richmond, Sunset, and Castro, we stage material over the front parapet with rope and pulley, or carry it through your interior with floor protection laid first, because there’s no alley or side gate to work from.
Parapet Flashing and Party-Wall Details
Most San Francisco flat roofs fail at the parapet, not in the field. The fog saturates stucco parapets for weeks, and old metal flashing pulls away from the wall. We install new counter-flashing and reglet details at every parapet, chimney, and party-wall intersection before we put membrane down. Ice and water shield goes at every penetration and shared-wall junction on every re-roof we do in San Francisco.
Roof Maintenance in San Francisco
Roof Maintenance in San Francisco is the cheapest way to avoid a five-figure re-roof, especially in the fog belt where flat membranes degrade from constant moisture cycling rather than rain. A maintenance visit runs $250 – $550 and includes clearing debris from drains and scuppers, re-sealing penetrations and pipe boots, checking parapet flashing, and documenting membrane condition with photos so you can track changes year over year. We recommend maintenance twice a year in the Outer Sunset, Inner Richmond, Twin Peaks, and any neighborhood where Karl the Fog parks for weeks at a time.
Drain and Scupper Clearing
Interior drains clog with redwood needles, eucalyptus debris, and algae that grows on chronically wet membranes. A clogged drain on a San Francisco flat roof means ponding water that accelerates membrane rot by years. We rod out every drain, check the overflow scuppers, and verify water moves off the roof before we consider the visit complete.
Membrane Condition Reports
If you’re thinking about selling a San Francisco home, a membrane condition report with photos and a written assessment helps you plan. We identify micro-cracking, blistering, and UV damage at the fog edge before they become leaks. Homeowners in the Mission and Potrero Hill, where sun exposure is higher than the western neighborhoods, often need more attention paid to UV degradation and less to algae growth. We adjust the maintenance scope by microclimate.
Trusted Brands We Service in San Francisco
We install and repair membrane and shingle systems using manufacturer-recognized brands including GAF, CertainTeed, and Tamko, along with Owens Corning, IKO, Atlas, and Boral where the roof profile calls for tile or specialty products. We keep common flashing profiles, adhesives, and membrane repair materials stocked locally for San Francisco jobs, which means shorter turnaround on repairs in Daly City and the Sunset without waiting on shipped parts. If your current roof is under manufacturer warranty, we document everything properly so the warranty stays intact. When you call (743) 200-8347, we’ll tell you which system fits your roof and your budget, with a written price before any work begins.
Common Roofing Company Problems We See in San Francisco Homes
- Fog-belt membrane saturation. Flat BUR and modified bitumen roofs in the Outer Sunset and Inner Richmond stay damp for weeks at a time, even when official rainfall is only about 20 inches a year. Algae and moss grow on the membrane, and micro-cracking from UV cycling at the fog edge destroys roofs that look fine from the street.
- Zero-lot-line access failures. Attached rowhouses in the Castro, Mission, and Western Addition share party walls and have no side yard. Every bundle of material has to be hoisted over the front parapet or carried through your living room, which adds real labor hours that a generic bid won’t account for.
- Parapet flashing separation. Stucco and old metal flashing at parapets pulls away from the wall after decades of fog saturation and thermal movement. Water gets behind the membrane at the wall line and travels inward, showing up as ceiling stains far from the actual leak.
- Interior drain failure. San Francisco flat roofs drain through interior drains, not gutters. When those drains clog or the drain flashing rots, water ponds and migrates through the roof assembly. A $300 drain repair ignored for a year becomes a $4,000 decking replacement.
Pricing for Roofing Company in San Francisco, CA
Roof repairs in San Francisco run $450 – $1,200 for typical flashing, penetration, and small membrane patches. A full re-roof on a flat built-up or modified bitumen roof starts around $12,000 and can reach $28,000 on larger homes with rotted decking, parapet rebuilding, or especially difficult hoist access. Residential Roofing replacements on attached rowhouses cost more than suburban homes because material staging over a front parapet and interior carry through occupied rooms add meaningful labor hours. We give you a written line-item price before any work starts, and that price doesn’t change once the job begins, unless you ask for additional scope in writing. Call (743) 200-8347 for a free estimate and we’ll walk your roof with you and explain exactly where the money goes.
We Also Serve Cities Near San Francisco
Our crews work throughout Roofing Company in San Francisco and the surrounding Bay Area communities. We regularly handle roofs in Daly City, Brisbane, Sausalito, and South San Francisco. Each of these cities has its own mix of housing stock and fog exposure, and we adjust our material specs and access planning accordingly. If you’re in any of these areas, call (743) 200-8347 and we’ll schedule a walk-through.
Serving San Francisco, CA - Our Local Coverage Area
We’re based in the San Francisco 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 San Francisco
Yes, and it’s one of the most common failure patterns we see in San Francisco’s fog belt. The marine layer saturates flat BUR and modified bitumen membranes for weeks at a time during summer months, and that chronic moisture wicks through micro-cracks and failing flashing joints. What looks like a “summer leak” is usually fog-driven saturation finding a path through a small membrane defect that only opens when the material is constantly damp. We can find it, patch it properly, and give you a written repair guarantee. Call (743) 200-8347 for an inspection, free.
Because your rowhouse has no side yard, so every bundle of membrane, board, and flashing has to be hoisted over the front parapet or carried through your occupied interior. That’s real labor, not a markup. A suburban house with a driveway and side gate lets a crew stage material in the yard and walk it up a ladder. In San Francisco’s attached Victorians and Edwardians, we’re roping material up three stories and protecting your hallways and staircases from debris. The access constraint adds hours to nearly every re-roof, and any accurate bid has to account for it. Ask any contractor to show you the line item for staging and access, call (743) 200-8347 for a written breakdown.
Almost never. San Francisco’s housing stock is overwhelmingly flat and low-slope, built for built-up roofing or modified bitumen membranes, not pitched asphalt shingle systems. Swapping a properly functioning flat membrane for architectural shingles on a Victorian parapet roof usually creates drainage problems, looks wrong on the building, and can void your home’s historical character. If you have a genuinely pitched roof, which is the exception in San Francisco, we’ll tell you and spec the right shingle product from GAF, CertainTeed, or Tamko. But if you have a flat roof, the right move is repair or replace the membrane, not convert it. We’ll give you an honest recommendation in writing. Call (743) 200-8347.
Look at three things: access and staging line items, membrane specification, and whether the bid includes party-wall notice and work-hour compliance. A bid that doesn’t show hoist labor or interior-carry time on a zero-lot-line home is either underestimating the job or planning to surprise you with a change order later. The membrane spec should match your roof profile, not a generic suburban system. And both bids should account for San Francisco’s noise ordinances and the reality of working on a shared wall with neighbors. If one bid is missing these line items, it’s not cheaper, it’s incomplete. We give you a written line-item estimate so you can actually compare. Call (743) 200-8347 and we’ll walk you through it.
Yes, and we do it as standard practice on every attached rowhouse job in San Francisco. Party-wall work means our crews are working directly against your neighbor’s wall, and hoisting material over a shared parapet affects their property too. We walk the schedule with your shared-wall neighbors before we start, explain the hoist plan, and give them our contact information if they have questions. It’s not legally required in every situation, but it’s the right thing to do on a dense block, and it prevents disputes that can stall a job mid-roof. On a recent zero-lot-line Edwardian in the Inner Richmond, our crew re-roofed a fog-saturated modified bitumen membrane for a homeowner who’d had three repairs leak again. Every bundle and roll came over the front parapet by rope and pulley because there’s no side yard in the Avenues. We stripped to sound decking, laid new underlayment and ice and water shield at the party-wall flashing and penetrations, re-set the interior drain, then walked the building’s shared-wall neighbors through the schedule before we started so no one was surprised by the hoist. The membrane has held tight through two fog seasons. Call (743) 200-8347 for your free estimate and we’ll handle the neighbor notice as part of the job.
Written by Grant Whitlock, Owner at Mercer Roofing, serving San Francisco since 2000.