Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Before
After
Before
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Before
AfterFast, Reliable Roof Installation Across Westmont
A full roof installation in Westmont typically runs $11,000 to $24,000 depending on roof size, slope, and the material spec your home actually needs. We’ve been out here long enough to know that a Westmont roof has to survive two very different weather patterns: daily marine-layer moisture and fall Santa Ana gusts. The wrong material choice on a 1950s low-slope bungalow won’t just wear out early. It will fail. Call (743) 200-8347 and we’ll walk your roof with you, write down an honest number, and send you the name and photo of the technician before anyone rings your doorbell.
Why Mercer Roofing Is Westmont’s Preferred Roof Installation Company
Homeowners across Westmont keep calling us for one reason that has very little to do with shingles. Before anyone steps onto your property, you get the technician’s name, photo, and a confirmation of who to expect at the door. Our installers arrive in clean, marked uniforms and present a photo ID badge before any work begins. That’s the Threshold Verified standard, and every Mercer location is contractually held to it. When we install a roof in Westmont, you know exactly who is on your property from the first knock to the final inspection.
Grant Whitlock, who leads our Westmont roofing work, will tell you the same thing he tells every homeowner we meet: if a contractor can’t name the building department that actually issues your permit, they haven’t done enough roofs here. Westmont is unincorporated Los Angeles County. The permit comes from the County’s building and safety office, not Inglewood’s or Hawthorne’s. We’ve seen too many homeowners get stalled at final inspection because a well-meaning contractor pulled a city permit by mistake. That mistake costs time, a re-fee, and sometimes a second inspection. We don’t make it.
Every installation comes with two things in writing before the first nail is driven: a fixed price and our 365-Day Done Right Promise. If the work isn’t right within a year, we make it right. Written guarantee on every repair, free second visit if a repair fails. That’s been the Mercer standard since we were founded in 2000 as part of the Threshold Group family.
Tile Roof in Westmont
Tile Roof replacement in Westmont is most common on the larger post-war ranch homes and a handful of mid-century builds scattered between Vermont Avenue and the 110 corridor. A full tile roof install here typically runs $18,000 to $42,000 depending on whether you choose a concrete or clay profile, and whether the original underlayment can be salvaged or must be stripped and re-laid. Most homeowners only consider tile once the old asphalt roof has failed twice in a decade and they’re ready to stop the cycle.
The Underlayment Is the Real Tile System
Tile gets the attention, but the waterproofing is the underlayment. In Westmont’s daily marine layer, a tile roof with old felt underlayment will let moisture through long before a tile ever cracks. We specify a premium synthetic underlayment, and on the perimeter where wind-driven rain gets underneath during Santa Anas, ice and water shield in the valleys and eaves.
Matching the Original Roof Lines
Many of these Westmont tile homes were built with specific eave profiles that sag or settle unevenly over six or seven decades. Before any tile goes back, we inspect the fascia and eave framing for rot and level any uneven sections. A tile roof on a wavy eave line looks wrong and traps water where it shouldn’t.
Roof Ventilation in Westmont
Roof Ventilation in Westmont is where we catch problems other installers skip entirely. The marine layer that blankets South LA most mornings doesn’t just wet the outside of your roof; it also pushes humidity into attic spaces that were never adequately vented when the house was built in the 1940s or 1950s. Proper ventilation work as part of a roof install in Westmont runs $1,200 to $3,800 depending on the number of intake and exhaust points your roof needs and whether we’re adding ridge vent, box vents, or a combination.
Why Marine-Layer Moisture Demands Balanced Venting
When warm attic air meets the cool, damp air that sits over Westmont every morning, condensation forms on the underside of the decking. That’s how you get sagging plywood, mold streaks, and shingles that blister from beneath. The fix is simple in principle: equal intake and exhaust, measured in net free area per square foot. We do the math on every install and show you the numbers.
Attic Fans That Actually Last
If your existing roof has a powered attic fan installed in the 1990s on a cheap rheostat, it’s probably dead and you don’t know it. We test every fan during a roof replacement and recommend what’s right for your roof, not what’s easiest to wire. A quality thermostatically controlled fan with stainless hardware runs $450 to $850 with installation, and it stops the condensation cycle that shortens roof life by years.
Trusted Brands We Service in Westmont
We install GAF, CertainTeed, Owens Corning, IKO, Atlas, Tamko, and Boral. For Westmont specifically, we keep a tight inventory of Atlas and Tamko high-wind profiles because the Santa Ana season punishes ordinary three-tab shingles in ways inland roofs never see. If you have a Boral tile roof that’s been patched by three different contractors over the years, we can bring it back to spec and file a workmanship record your insurance company will actually accept. We don’t push one brand. We push the one that matches your roof’s slope, exposure, and the marine conditions it sits in.
Common Roof Installation Problems We See in Westmont Homes
- Multi-layer tear-offs on postwar low-slope roofs. Many Westmont roofs from the late 1940s through the 1960s carry two or three layers of patched-over material. County code now requires stripping to decking before a compliant re-roof, and skipping that step is exactly what fails a County inspection.
- Rusted fasteners and drip edge from daily marine moisture. Standard electro-galvanized nails and thin drip edge corrode within a few seasons of morning damp. We specify hot-dip galvanized fasteners and stainless flashing on every exposed edge to stop the rust cycle.
- Santa Ana wind damage at the roof perimeter. Fall gusts peel improperly fastened membrane edges and ridge caps. The fix starts with correct starter strip placement, proper nailing patterns per manufacturer spec, and sealed membrane edges that a gust can’t get under.
- Wrong-jurisdiction permits. Contractors used to Inglewood or Hawthorne city workflow sometimes pull a city permit by mistake. Westmont has no city hall. The permit must come from the LA County Department of Building and Safety in Norwalk or Altadena. A wrong permit fails inspection and triggers a re-fee.
Pricing for Roof Installation in Westmont, CA
An asphalt shingle roof installation on a typical Westmont bungalow runs $11,000 to $18,000. A full tile roof replacement runs $18,000 to $42,000. Flat and low-slope membrane systems using torch-down or modified bitumen run $13,000 to $22,000 depending on deck condition and the number of layers being stripped. Coastal-spec metal trim, hot-dip fasteners, and upgraded underlayment add 10% to 15% to the inland-spec version of the same job. The cheaper spec fails within a decade here. We’ve replaced enough of it to know. Call (743) 200-8347 and we’ll give you a written quote you can hold us to.
We Also Serve Cities Near Westmont
Our Roof Installation team serves Westmont and a number of surrounding communities throughout Los Angeles County, including Los Angeles, San Diego, San Jose, and San Francisco. If you’re just outside Westmont, Roof Installation in Westmont standards still apply to your project, and we’re happy to schedule a site visit wherever your roof is. Call the office and we’ll route the nearest crew to you.
Serving Westmont, CA - Our Local Coverage Area
We’re based in the Westmont 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 Roof Installation in Westmont
The LA County Department of Building and Safety handles all roofing permits and inspections in Westmont under Title 26 of the LA County Code, with permits issued through County offices in Norwalk or Altadena. There is no Westmont city hall, no local counter, and no city-level permit path. Call (743) 200-8347 and we’ll pull the right County paperwork from day one so your final inspection is a formality, not a surprise.
Westmont sits roughly 8 to 10 miles inland from the Pacific, inside the marine-layer belt that leaves roofs damp most mornings of the year. That daily moisture accelerates granule loss on asphalt shingles, feeds algae streaking across flat-roof membranes, and rusts standard fasteners and drip edge within a few seasons. The fix is a coastal-spec install: hot-dip galvanized or stainless fasteners, upgraded underlayment, and edge detailing built to handle persistent damp rather than survive it. Call (743) 200-8347 for a written quote on a roof built for this specific climate.
No, and a County inspector will agree with us. Most Westmont low-slope roofs from that era already carry multiple patched-over layers that hide bad underlayment and soft decking. Title 26 requires stripping to the original decking before a compliant re-roof, and covering old layers only guarantees a failed inspection and a do-over. We strip, inspect the decking, replace any soft spots, then build the new system up properly. Call (743) 200-8347 for a straight answer on what your specific roof needs.
Santa Ana gusts hit the roof perimeter first and they exploit any edge that isn’t fully sealed and fastened. We install starter strip along the entire eave, use manufacturer-specified nailing patterns on every shingle, and mechanically fasten and seal the membrane edges on flat or low-slope roofs so wind can’t get under them. On ridge caps, we go past the standard nailing pattern to add extra fasteners where gusts concentrate. Call (743) 200-8347 and ask us to show you this on your own roof before we start.
The coastal-spec version uses hot-dip galvanized drip edge and fasteners, stainless flashing, upgraded synthetic underlayment, and ice and water shield at the perimeter. It adds 10% to 15% to the total, and it’s the reason a Westmont roof lasts 25 years instead of 12. The inland-spec version cuts those corners, and every corner that gets cut is exactly where the marine layer attacks first. We install the coastal spec on every Westmont roof because we’ve torn off too many inland-spec jobs that died young. Call (743) 200-8347 for a written price on both, and we’ll show you the ten-year math side by side.
Your Westmont Roof, Built for Westmont Weather
We just wrapped a full tear-off on a 1948 low-slope bungalow near the 110 freeway side of Westmont, where the original roof carried three layers of patched-over hot mop under a failing mod-bit cap. After stripping to original decking, we laid down new underlayment and ice and water shield at the perimeter, then set hot-dip galvanized drip edge and fasteners so the marine-layer moisture wouldn’t eat the metal the way it had eaten the last install. The homeowner finally stopped chasing leaks every Santa Ana wind event. That’s what a Westmont-specific install looks like, and it’s exactly what we’ll spec for your home. Call (743) 200-8347 to schedule your free estimate, and we’ll send the name and photo of your technician before they arrive.
Written by Grant Whitlock, Owner at Mercer Roofing, serving Westmont since 2000.