Metal roofing
Tile roofing
GAF
Owens Corning
Flat & low-slopeFree roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Boral Flashing Replacement: The San Francisco Owner’s Guide
We stock and install Boral-compatible flashing replacement in San Francisco, and most homeowners pay between $450 and $1,400 installed depending on location, accessibility, and how much surrounding material has to come apart. We carry Boral flashing profiles on our trucks, so if it’s a straightforward pipe collar or headwall flashing, we can often swap it the same day we diagnose it. Most San Francisco owners find out their flashing failed the same way: a water stain on the ceiling that wasn’t there last week, or a drip near the chimney only when the fog sits low and heavy.
Flashing is the metal or membrane work where the roof meets something else – a pipe, a wall, a chimney, a skylight. Boral’s roof systems are built to shed water for decades, but flashing is the joint work that takes the abuse from San Francisco’s wet winters, salt air in the Sunset and Richmond, and the constant expansion and contraction that comes with temperature swings. When flashing fails on a Boral roof, it’s rarely because the tile or steep-slope material gave up. It’s because the transition point finally let go.
Which Boral Models This Applies To
Boral’s steep-slope roofing lines – Bermuda, CedarLite, and Mission-style profiles – all use similar flashing logic at penetrations and transitions, but the exact profile depends on the tile shape you have. The barrel-shaped profiles need a different step-flashing layering schedule than a flat-profile tile. If you still have the Boral installation guide from your original build, it’ll list the flashing spec by series. If you don’t, we match by measuring the tile profile and the penetration type on site.
A common compatibility gotcha: Boral tile roofs in San Francisco are frequently installed over older wood sheathing, especially on Victorian and Edwardian-era homes. The flashing detail has to account for that sheathing movement. We’ve seen failed flashing on Sunset District homes where the original installer used a generic apron flashing that didn’t match the Boral profile’s water channel. You need flashing that follows the tile’s contour, not just a flat piece of metal tucked behind it.
Birchbark Roofing San Francisco is an independent service provider and we are not affiliated with Boral. If you have an active Boral installation warranty, we’ll document the condition we find so you can file a materials claim with the manufacturer. For replacements, we use OEM Boral flashing parts where the profile demands it, and quality aftermarket equivalents where a standard step flashing does the job and meets the same spec.
Styles & brands we work with





Signs Your Boral Flashing Replacement Is Failing
- Water staining on ceilings or upper walls after rain. This is the classic first sign. Flashing failures almost always show up as interior staining near a chimney, wall, or skylight before you see anything wrong from the outside. The water tracks along sheathing and finds the lowest point to drip.
- Visible rust or corrosion on metal flashing at the chimney or roof-wall joints. San Francisco’s marine air accelerates rust on steel flashing, especially within a mile of the ocean. Once rust perforates the metal, water gets behind it and into the decking.
- Lifted or curled flashing at pipe penetrations. The rubber boot around a plumbing vent shrinks and cracks over time. When the boot lifts off the pipe, water follows the pipe straight down into the attic.
- Damp musty smell in attic spaces. Sometimes flashing fails without ever staining a ceiling. The water runs down the sheathing and evaporates, but the moisture lingers in insulation and framing. If your attic smells earthy after winter rains, flashing is a prime suspect.
- Loose or dislodged tile near roof edges and valley transitions. When flashing loses its grip or the underlayment below shifts, tiles can loosen at the exact points where flashing lives. Movement there means the water channel is compromised.
See the difference
Before
After
Before
After
Before
AfterReplacement Cost & What’s Included
Boral flashing replacement in San Francisco typically runs $450 to $1,400 installed. A simple plumbing vent boot is the low end. A full chimney apron, side-wall step flashing, and underlayment repair on a steep two-story roof is the high end.
Every price we quote includes the removal of old flashing, inspection of the sheathing underneath, new underlayment where needed, the flashing itself, and re-securing the Boral tiles around the work. You’ll see the line items before we start, with the exact dollar figure Erik Lindgren writes down after walking your roof. No open-ended time and materials. No surprise change orders.
Our 365-Day Done Right Promise covers this work. If the flashing doesn’t hold through a full San Francisco winter, we make it right. And you get a written price in dollars before a single tile moves.
DIY or Call Us?
You can safely look for yourself: after a rain, check around chimney bases and roof-wall joints from the ground with binoculars. Look for rust streaks, lifted flashing, or missing tile. Inside, check the attic for damp framing near any penetration. That’s safe and useful.
What you shouldn’t do is climb a steep Boral tile roof and attempt a flashing repair. Tiles crack under foot weight if you don’t know which to step on. The roof is a two-story fall risk on most San Francisco homes, and improper flashing installation voids the roof’s water barrier. Flashing detail work is measured in inches, not feet – the seal, the overlap, the counterflashing reveal all have to be right. This is one of those repairs where the cost of doing it wrong is a rotted deck and a much bigger project in two years. If you want to talk it through before deciding, call (831) 228-3330 and ask for us to come take a look.
FAQs
Expect 15 to 25 years from steel flashing in San Francisco, with homes near the ocean in the Sunset and Richmond trending toward the lower end due to salt air. Rubber pipe boots last 10 to 15 years. Copper flashing outlasts all of it and is a common upgrade for landmark homes. If your flashing is older than that, plan for replacement before it leaks. For a specific assessment, call (831) 228-3330.
In most cases, no. Once flashing rusts through or the seal has broken, a patch buys you a season at best. We’ve pulled patches off San Francisco roofs that were doing nothing but hiding the damage underneath. The reliable fix is to remove the failed piece, inspect what’s behind it, and install new flashing with new sealant. If the damage is a pinhole in a boot, we’ll sometimes patch that as a stopgap while you schedule the full swap – but we’ll be honest that it’s temporary. Call (831) 228-3330 for an exact recommendation on your roof.
Most single-penetration flashing replacements take 2 to 4 hours on site. A chimney with multiple flashings or a wall transition that requires removing several courses of tile takes a full day. San Francisco fog can extend any roof job by an hour or two while surfaces dry. We’ll tell you the time window when we set the date. Call (831) 228-3330 to schedule.
We stock common Boral-compatible flashing profiles and pipe boots on our trucks, including sizes matched to Boral tile’s water channel. Specialty copper or custom-bent flashing takes 3 to 5 business days to fabricate. We also stock flashing for GAF, Owens Corning, and CertainTeed roof systems for anyone with a mixed-material roof. Call (831) 228-3330 and we’ll tell you what we can do today.
Call (831) 228-3330 to schedule your free Boral flashing replacement estimate in San Francisco. A written price before a single shingle moves – that’s just how the job starts.
Written by Erik Lindgren, Owner, Birchbark Roofing San Francisco at Birchbark Roofing San Francisco, serving San Francisco and nearby areas.