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CertainTeed Flashing Replacement: The Los Angeles Owner’s Guide
Replacing failed flashing on a CertainTeed roof in Los Angeles typically runs between $350 and $900 installed, depending on how many linear feet need replacing and whether we’re dealing with step flashing, pipe boot flashing, or valley metal. We keep common CertainTeed-compatible flashing profiles and replacement pipe boots stocked, so most jobs are done in a single visit, often the same week you call. Homeowners usually discover the problem one of two ways: a water stain on the ceiling after a heavy rain, or a roofer pointing out corroded metal during an unrelated inspection.
Flashing is the quiet workhorse of your roof. It’s the metal that gets bent, cut, and tucked at every transition point where shingles meet a wall, chimney, skylight, or vent pipe. Universal shingles get the attention, but flashing keeps water out of the joints. CertainTeed roofs can last 25 to 50 years depending on the shingle line, but the flashing underneath often fails much sooner, especially here where heat and coastal air work on exposed metal year-round.
Which CertainTeed Models This Applies To
CertainTeed flashing replacement isn’t limited to any single shingle line. We install flashing on roofs with Landmark, Landmark Pro, Presidential Shake, Grand Manor, XT 30, XT 25, and the entire Integrity Roof System. The flashing material itself is independent of the shingle product, but CertainTeed’s installation specs call for specific step flashing dimensions and minimum lap requirements that we follow to keep your system warranty intact.
Step flashing for CertainTeed roofs is most commonly 4-inch by 4-inch by 10-inch galvanized steel, though we also use pre-painted aluminum in coastal neighborhoods like Playa del Rey and San Pedro where salt air eats bare steel faster. Pipe boot flashing comes in two sizes: 1½-inch and 2-inch, and CertainTeed’s own pipe boots use a synthetic rubber collar that holds up better than the cheap neoprene you’ll find on economy boots at big-box stores. The key matching point is the slope and the existing counter-flashing depth. If your home was built before 2000 and has original flashing, there’s a good chance the code minimums have changed since installation.
We’re an independent Los Angeles roofing contractor, not a CertainTeed-owned installer. That means we match compatible flashing without being tied to a single supplier, which usually gets the job done faster and at a better price.
Styles & brands we work with






Signs Your CertainTeed Flashing Replacement Is Failing
- Water staining along interior walls or ceilings near a chimney or skylight. This is the classic signature of failed step or counter flashing. The water travels down the flashing channel and finds a path at the first break in the metal.
- Rust streaks running down from a pipe boot or wall junction. Once corrosion breaks through the galvanized coating or the aluminum oxide layer, the metal starts losing its water-shedding ability and small leaks begin. In Los Angeles, we see this most often on south-facing and ocean-facing elevations where UV and salt air hit hardest.
- Lifted or curling flashing where it meets the shingle course. Thermal expansion over years of 90-degree summers and cold desert nights slowly unseats flashing. Once it lifts, wind-driven rain gets under it.
- Granule loss around a penetration. It sounds counterintuitive, but worn shingles around a vent pipe or chimney often mean water has been pooling or channeling there longer than it should. The shingles fail because the flashing above them stopped doing its job first.
- Damp attic insulation or daylight visible at a roof-to-wall intersection. If you can see light through a gap where the roof meets a vertical wall, water gets through too. That’s a direct sign the step flashing needs replacement, not repair.
See the difference
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Before
AfterReplacement Cost & What’s Included
In Los Angeles, a straightforward pipe boot flashing replacement on a single-story home runs $350 to $500. Step flashing along a chimney or sidewall runs $500 to $900, depending on the length of the run, whether we need to remove and reinstall shingle courses, and whether the counter-flashing needs to be cut into stucco or brick. Valley flashing sits in a similar range. Here’s what typically drives the price:
- Linear feet of flashing. More wall junction, more material, more labor.
- Roof pitch and access. Steep roofs on hillside lots in Echo Park or Mount Washington take longer and require more safety setup, which adds labor hours.
- Material choice. 24-gauge galvanized is the workhorse; copper is three to four times the material cost, and some homeowners on historic properties in Pasadena-adjacent neighborhoods choose it for the look.
- Counter-flashing work. Cutting a clean reglet line into stucco or brick with a diamond blade adds time, but skips this step and the repair won’t last.
Every flashing replacement we do includes a written price before we start, with no change orders, and a 365-Day Done Right Promise. If the repair fails within a year, we come back and fix it free.
DIY or Call Us?
Flashing replacement is not a beginner DIY job. The materials are inexpensive, which makes it tempting, but the repair fails when the lapping sequence is wrong or the counter-flashing isn’t seated properly. Water doesn’t care how confident you were. It finds the gap.
What a homeowner can safely do: check visible pipe boots on a low-slope roof from a ladder (never on a steep roof), look for rust streaks, and clear debris from valleys. What you should not do: lift existing shingles to inspect step flashing, attempt to remove and re-bend metal, or work on a roof with a pitch steeper than 4:12 without a harness and roof jacks. A fall from a single-story roof in Los Angeles sends people to the ER every week.
If you suspect flashing failure, call us at (213) 521-8272. We’ll send a technician who is background-checked, identity-verified, and arrives in uniform with a photo ID badge. You’ll know exactly who is coming before they ring the bell, because we send their name and photo ahead of time. That’s the Threshold Verified standard we’re held to, and it matters when you’re deciding who gets to walk on your roof.
FAQs
Galvanized step flashing typically lasts 15 to 25 years in Los Angeles; aluminum lasts longer in coastal zones but corrodes faster against certain treated woods. Heat and UV are bigger factors here than rain, because the expansion and contraction cycle slowly loosens fasteners and breaks sealant. Pipe boot rubber collars fail fastest, usually within 8 to 12 years. If your flashing is older than two decades, it’s time for an inspection. Call (213) 521-8272 and we’ll tell you honestly whether it needs replacing or has years left.
Sometimes, yes. A lifted corner or a failed sealant bead can often be fixed in under an hour with new fasteners and a high-quality urethane sealant. But once the metal is corroded through, bent beyond reshaping, or the lap sequence is wrong, patching it just buys a season at best. We’ll tell you if a repair makes sense and give you a written price for both options before any work starts.
Most flashing replacements in Los Angeles are completed in half a day to a full day. A single pipe boot swap takes under two hours. A full chimney step flashing and counter-flashing job with stucco work takes most of a day. We protect the area underneath, clean up all debris, and walk you through what we did before we leave.
Yes. Our trucks carry galvanized and painted aluminum step flashing in common Los Angeles profiles, both pipe boot sizes, and a selection of preformed valley metal. If the job calls for copper or a custom profile, we order it and have it within a few days. We also keep flashing stock compatible with other major brands, including GAF and Owens Corning, so the brand of your shingles doesn’t delay the repair.
If you have questions we didn’t answer here, or if you’ve spotted any of the warning signs above, call (213) 521-8272 for a free estimate. A live person answers, day or night. We’ll talk through what you’re seeing, help you figure out whether it’s actually flashing or something else, and give you a written price before anyone sets foot on your roof. A roof should be the last thing on your mind – let’s keep it that way.
Written by Grant Whitlock, Owner, Mercer Roofing Co at Mercer Roofing Co Los Angeles, serving Los Angeles and nearby areas.