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CertainTeed Roofing in South Gate, CA | Mercer Roofing Co Los Angeles
We provide independent CertainTeed roofing service across South Gate, from shingle replacement to full tear-offs and re-roofs on the city’s 1920s – 1950s homes. The one thing that makes our CertainTeed work here different is what we find underneath: nearly every pre-1950 South Gate roof hides original wood shake under multiple asphalt layers, which changes how the tear-off goes, what the deck needs, and why our bids look different from a neighboring city’s. Call (213) 521-8272 for a free estimate, and we’ll tell you exactly what’s on your roof before anyone climbs a ladder.
We work on all major CertainTeed product lines: Landmark architectural shingles, XT 25 3-tab, Presidential Shake, and Flintlastic SA low-slope membrane. Mercer Roofing Co Los Angeles is an independent CertainTeed service provider; we are not manufacturer-affiliated or authorized. What that means for you is straightforward: we install genuine CertainTeed components because they work, and we tell you the truth about what your roof actually needs. South Gate’s building department now requires full tear-off before any new CertainTeed system on older homes, so we plan for dump fees, deck corrections, and the labor those extra layers demand. CertainTeed sales & service is a core part of what we do every week across this city.
Written by Grant Whitlock, Owner at Mercer Roofing Co Los Angeles, serving South Gate since we opened our doors.
Why South Gate Residents Choose Us for CertainTeed Service
Grant Whitlock grew up in Eagle Rock and trained in the building trades program at Los Angeles Trade-Technical College before spending two decades doing roofing work across the LA basin, flat torch-down in the Valley, clay tile on hillside bungalows, composition shingles everywhere else. When a South Gate homeowner calls about a CertainTeed Landmark roof that’s losing granules or an XT 25 that cracked along the butt joints, he knows what’s happening because he’s pulled those shingles off houses on Firestone Boulevard and Long Beach Boulevard more times than he can count.
South Gate’s housing stock is dense, modest, and old. The single-family homes built between the 1920s and 1950s were often roofed with wood shake first, then asphalt shingles patched over that, sometimes two or three layers deep. When we tear off a CertainTeed roof in South Gate, we expect to find the original cedar underneath. That’s not true everywhere, and crews that don’t work this city regularly get surprised by the weight, the dump fees, and the deck rot. We don’t. Every technician who arrives at your door is background-checked, identity-verified, and wearing a photo ID badge, part of the Threshold Verified standard. You’ll get that technician’s name and photo before they show up. A live person answers our phone 24/7, not a voicemail. That matters when you’re home alone or have young kids and want to know exactly who’s walking up your driveway.
Founded in 2000 and part of the Threshold Group family of home-service companies, Mercer Roofing gives you a written price before any work starts. Every repair includes a written guarantee, and if a repair fails within 365 days, we return and make it right, free second visit included. That’s the 365-Day Done Right Promise.
Styles & brands we work with






Common CertainTeed Roofing Problems We Solve in South Gate
- Granule loss on Landmark shingles, especially south-facing slopes. After about a decade of South Gate’s intense summer UV, Landmark architectural shingles lose granule adhesion. Once the asphalt mat is exposed, the marine layer keeps it damp for hours each morning, and the shingles start spalling. Homeowners notice grit in their gutters first. We replace field-cut pieces when the roof is under 8 years old; after that, a full re-roof with new Landmark usually saves money over chasing patches.
- Cracked seals on XT 25 3-tab butt joints. South Gate’s cool, wet winters are the problem here. XT 25 sealant strips crack at the butt joints during temperature swings, and driven rain finds its way under the shingle and into the old shake layer below. If you see shingles lifting at the bottom edge after a storm, that’s what’s happened.
- Algae streaking on Presidential Shake’s north-facing slopes. The thicker profile of Presidential Shake traps moisture in shaded areas. On South Gate homes with north-facing roof planes, morning fog keeps those slopes damp well into the afternoon. Algae sets in, and over time the streaking loosens the laminate bond between the shake layers.
- Flintlastic SA end laps lifting on flat porch roofs and carport additions. South Gate summers push heat into flat low-slope surfaces. When Flintlastic SA wasn’t rolled with a weighted roller during installation, the factory-applied selvage edge lifts during heat expansion. We find this on flat porch roofs and carport additions all over South Gate, and the fix is re-adhering the lap and rolling it properly.
- Valley leaks where old flashing finally fails. Valleys are the weak point on any CertainTeed system, but on South Gate’s older homes, the valley metal often dates back to the original construction. Two winters of concentrated runoff can push water under the shingles and into the deck. We reframe the valley, install CertainTeed WinterGuard, and re-shingle it so the leak stops for good.
CertainTeed Service in South Gate: What Local Conditions Mean for Your Equipment
In South Gate, nearly every reroof on a pre-1950 home uncovers a hidden layer of original wood shake under two or three layers of asphalt. The city’s building department now requires full tear-off before any new CertainTeed system goes on, which means our dump fees and labor for deck sheathing corrections are higher than in neighboring Lynwood or Huntington Park, where patch-overs are still grandfathered on smaller jobs. This is the single biggest factor in why a South Gate CertainTeed re-roof bid looks the way it does, and it’s something no generic roofing page will tell you. The original 1920s cedar shakes are brittle, often rotted to mulch where roof penetrations leaked over the years, and the deck boards underneath have usually shifted. When we tear off a South Gate roof with three layers of asphalt over cedar, the waste haul alone is double what a single-layer job produces. We factor that into the written price you get before work starts, so there’s no surprise when the dumpster shows up. If you’re comparing bids between South Gate and a neighboring city, ask whether the other contractor included full tear-off and deck corrections. We do, every time.
Last month our crew tore off a Landmark roof on Firestone Boulevard near South Gate Park where the homeowner’s north-facing valley had been leaking for two winters. Under the CertainTeed shingles we found the original 1920s cedar shakes rotted to mulch and a valley metal that had never been replaced. We reframed the valley with new 2x decking, installed CertainTeed WinterGuard in the valley, and re-roofed with Landmark in Georgetown Gray. The owner stopped placing buckets after the first heavy rain.
CertainTeed Models & Products We Service in South Gate
We service the full CertainTeed residential line. Landmark architectural shingles are the workhorse on most South Gate bungalows, and we stock the common colorways locally for fast turnaround. XT 25 3-tab still appears on older additions and detached garages. Presidential Shake shows up on larger 1950s homes and a few custom builds. Flintlastic SA covers flat porch roofs, carport additions, and the low-slope sections common on South Gate’s multi-family buildings along major corridors.
On parts, our approach is simple: we install genuine CertainTeed accessory components, DiamondDeck underlayment, Shadow Ridge cap shingles, and CertainTeed starter strips, because aftermarket substitutes fail at the exact transitions where South Gate’s marine layer lingers. The starter strip and cap row are where water intrusion starts on any shingle roof, and using the manufacturer’s components there is the difference between a roof that lasts 20 years and one that needs valley repairs in five. For tile underlayment replacement, we remove the tile, replace the underlayment with CertainTeed membrane where appropriate, and re-set the existing tile if it’s still sound.
See the difference
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AfterCertainTeed Service Pricing in South Gate
Most CertainTeed roof work in South Gate falls into these ranges:
- Shingle replacement (single shingle or small section): $180 – $400 depending on location and accessibility.
- Valley repair with new metal and WinterGuard: $650 – $1,400 per valley.
- Flintlastic SA patch on a flat roof: $350 – $800.
- Partial re-roof (one slope, including tear-off): $2,800 – $6,500.
- Full CertainTeed Landmark re-roof on a typical 1,000 – 1,400 sq. ft. South Gate home: $9,500 – $16,000.
What drives the price in South Gate specifically is the tear-off depth. A house with one layer of asphalt over plywood costs less to re-roof than a 1940s bungalow with two asphalt layers over original wood shake. Deck sheathing corrections add materials and labor. We give you a written, line-item price before any work starts, so you can see exactly where the money goes. Call (213) 521-8272 to schedule your free estimate.
Serving South Gate, CA - Our Local Coverage Area
We’re based in the South Gate 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 – CertainTeed Roofing in South Gate
That’s algae feeding on moisture trapped in the shingle’s granule surface. The north-facing slope, which on many South Gate homes faces the cemetery and other tree-lined streets, stays damp from morning fog and shade long after the south slope dries out. Landmark shingles are algae-resistant, but no shingle is algae-proof after a decade of persistent moisture. The streaks loosen granules over time and shorten the roof’s life. We can clean the slope and treat it, but if the granule loss is advanced, a partial or full replacement is the honest fix. Call (213) 521-8272 and we’ll take a look at what’s actually happening up there.
Yes, to a point. Presidential Shake is still in production, so we can source the same color family, but years of South Gate sun fade the existing shingles, and a brand-new bundle won’t match a roof that’s been up for a decade. If the damaged side is small, we’ll field-cut and blend pieces from less visible areas. If a full slope needs replacement, the color difference will be noticeable. We’ll show you samples before we quote so you know exactly what you’re getting.
Because South Gate’s building department enforces full tear-off on pre-1950 homes before any new roofing system goes on. That means we haul off every layer, asphalt and original wood shake included, before we install your new CertainTeed roof. Cudahy and some neighboring cities still allow a recover on certain smaller jobs, which skips the tear-off and the dump fees. Your South Gate bid is higher because it includes more labor, heavier waste hauling, and any deck repairs we find once the old layers come off. Call (213) 521-8272 for a line-item quote so you can see the difference yourself.
XT 25 is a 3-tab shingle with a sealant strip at the butt joint, and that sealant is the first thing to fail in South Gate’s cool, wet winters. When the sealant cracks, the shingle tabs lift, driven rain gets underneath, and repeated wet-dry cycles weaken the asphalt until cracks form along the bottom edge. Six years is short for XT 25, but it happens on homes where the original underlayment is failing or the deck moves with temperature swings. A repair can address the cracked shingles, but if the underlying problem is widespread, a re-roof with Landmark architectural shingles is the better long-term move.
Flintlastic SA is a self-adhered low-slope membrane that works well on flat sections like carport additions, if it’s installed correctly. The key is rolling the laps with a weighted roller so the selvage edge bonds fully. In South Gate’s summer heat, poorly rolled laps lift, and the morning fog gets under them. We install Flintlastic SA on flat roofs and porch roofs all over South Gate, and we re-roll every lap before we walk off. Call (213) 521-8272 for a free estimate on your carport roof.
Service Areas Near South Gate
We serve South Gate service area and the surrounding cities. Our crews regularly work in Lynwood, Cudahy, Bell Gardens, and Gardena, and we cover the wider LA basin including CertainTeed service in Los Angeles and CertainTeed service in Burbank. If you’re near the South Gate border, call and ask. We’re usually within a short drive.
Book Your CertainTeed Service in South Gate Today
If your CertainTeed roof is showing granule loss, lifting shingles, or valley leaks, call Mercer Roofing Co Los Angeles at (213) 521-8272. We’ll send a background-checked, photo-badged technician to inspect it, give you a written price before any work starts, and if it’s a repair, put the guarantee in writing. A roof should be the last thing on your mind, let’s keep it that way.
Written by Grant Whitlock, Owner at Mercer Roofing Co Los Angeles, serving South Gate since our doors opened.