Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Before
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Before
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AfterFast, Reliable Roof Installation Across Commerce
Roof installation in Commerce, CA typically costs $7,500 – $29,000 depending on whether you’re re-covering a residential bungalow or tearing off and replacing a flat membrane system on a commercial warehouse. Most Commerce projects are commercial flat-roof scopes, and we schedule most jobs within 1 – 2 weeks of the written estimate. If your roof off Slauson Avenue or Telegraph Road is failing, call (743) 200-8347 for a free, no-pressure estimate from Mercer Roofing.
Commerce is different from every city around it. Nearly the entire municipality is industrial, which means your roofer needs to understand TPO and EPDM membranes, Title 24 cool-roof compliance, and how to stage a crew on a lot with no room to spare. We do this work every week in Commerce, and we know the city’s permit office, its load requirements, and the specific headaches that come with reroofing a 1950s warehouse that has three layers of old roofing stacked on its deck.
Why Mercer Roofing Is Commerce’s Preferred Roof Installation Company
We’ve installed and repaired roofs in Commerce long enough to know that every job here has a complication hiding somewhere: a party wall, a restricted alley, a permit department that wants structural load numbers before it’ll stamp anything. That’s why every Mercer project starts with a written price, not a verbal guess. Before work starts, you’ll have a line-item scope, a fixed price, and our 365-Day Done Right Promise in writing. If something isn’t right within a year, we come back and make it right.
Our technicians are background-checked, identity-verified, and uniformed. Before anyone shows up at your Commerce property, we send their name and photo ahead. At the door, they present a photo ID badge. This is the Threshold Verified standard, and every Mercer location is contractually held to it. For homeowners and facility managers in Commerce who don’t want to open the door to an unidentified stranger, that badge matters.
Grant Whitlock leads our team, and he’s built the Commerce operation around one rule: the person who knocks on your door is exactly who we said was coming. No subs we’ve never met, no day-labor fill-ins. A live person answers our phone 24/7, so when you call (743) 200-8347 at 6 a.m. because a warehouse roof is leaking onto inventory, you talk to a human, not a voicemail.
Roof Flashing Installation in Commerce
Roof flashing installation in Commerce is the most commonly under-specified line item on flat-roof projects, and it’s where we see the most callbacks from other contractors’ work. Flashing is the metal or membrane collar that seals the joints where a roof meets a wall, a curb, a vent pipe, or a parapet. In Commerce, nearly every commercial building has parapet walls, rooftop HVAC units, and utility penetrations, so flashing is not an add-on; it’s the difference between a roof that holds and one that leaks at the first hard rain.
What does roof flashing installation cost in Commerce? On a typical flat commercial roof, a full flashing detail replacement runs $1,200 – $4,800 depending on the number of penetrations, parapet linear footage, and whether we’re retrofitting existing terminations or starting clean. On a residential bungalow with a shingle roof, flashing around chimneys, skylights, or vent pipes usually runs $450 – $1,800. We write these numbers into the quote as separate lines so you can see exactly what you’re paying for.
Parapet and party-wall flashing details
Older Commerce buildings share walls with neighbors. The flashing where a roof ties into a party wall is the first place water gets in, and if the adjoining property owner isn’t notified before we touch that wall, you can end up in a dispute. We document the shared wall’s condition before work begins, give written notice to the adjoining owner, and install a proper two-piece counterflashing system so the seal holds for decades.
Curb and penetration flashing on flat roofs
Every HVAC unit, exhaust fan, and plumbing vent on a Commerce flat roof needs a watertight curb with membrane flashing turned up at least 8 inches. We use compatible TPO or modified bitumen flashing, never a mismatched patch, so the manufacturer’s warranty stays valid.
TPO Roofing Installation in Commerce
TPO roofing installation in Commerce is the most common commercial roof system we install, and for good reason. TPO (thermoplastic polyolefin) is a white, heat-reflective single-ply membrane that stands up to the intense urban heat island effect we get around the I-5/SR-60 corridor, where acres of dark flat rooftops push surface temperatures well above what nearby residential neighborhoods experience. A properly installed TPO roof on a Commerce warehouse also helps you meet California Title 24 cool-roof requirements without needing an additional reflective coating.
What does TPO roofing installation cost in Commerce? For a typical 10,000-square-foot flat warehouse roof, full tearoff and new TPO runs $6.50 – $9.00 per square foot installed, so roughly $65,000 – $90,000. That includes tapered insulation where needed to correct ponding, new edge details, and all flashing work. We give you a written line-item quote before anything is ordered.
Fully adhered TPO systems
For occupied buildings where odor from adhesives isn’t a concern, a fully adhered TPO system gives you the best wind uplift ratings and the cleanest look. It’s what we recommend for most Commerce warehouses because the wind can funnel hard between industrial buildings.
Mechanically attached TPO and existing roof overlays
If your existing roof has a single clean layer and the deck can support it, a mechanically attached overlay can save real money. But we’ll tell you plainly: many Commerce buildings have two, three, even four layers of old modified bitumen already up there, and overlaying again is not an option those buildings can afford structurally. A load evaluation tells you before the permit is pulled.
Trusted Brands We Service in Commerce
We install and repair TPO and shingle systems from GAF, CertainTeed, Owens Corning, and Atlas, among others. For Commerce’s commercial flat-roof stock, we most often spec TPO membrane from brands we know hold up under Southern California sun and industrial air quality. We keep local inventory of common fastening components, membrane, and flashing materials so your Commerce project doesn’t stall waiting on a cross-country shipment. When we say we’ll start on a date, we have the material to back it up.
Common Roof Installation Problems We See in Commerce Homes
- Stacked roofing layers from decades of overlays. Many postwar Commerce industrial buildings have never had a full tearoff. We regularly expose three or four accumulated layers of modified bitumen or BUR, and that extra weight can exceed what the deck was designed to hold. A structural load evaluation is not optional on these jobs.
- Ponding water at low-slope drainage points. Commerce’s flat roofs are not actually flat; they’re low-slope, and when drains clog or the slope settles, water stands. Standing water degrades membrane adhesives and leads to delamination. We correct the slope with tapered insulation before installing the new system.
- Party-wall flashing failures from unpermitted access. When a neighboring roofer works on a shared wall without notifying the other property owner, flashing gets torn up and left loose. Leaks start on both sides. We sort out access agreements before the tearoff starts.
- Street and alley staging conflicts. Tight Commerce lots don’t have room for a dumpster, a material lift, and a delivery truck all at once. Poor staging is why some roofing projects here get red-tagged by the city. We coordinate deliveries by time slot and keep debris containers off the public right-of-way.
Pricing for Roof Installation in Commerce, CA
What can you expect to pay for roof installation in Commerce? For a small residential bungalow reroof with architectural shingles, the range is typically $7,500 – $14,000 for a full tearoff, new underlayment, new flashing, and installation. For a flat-roof commercial building, TPO installation lands between $6.50 and $9.00 per square foot, which puts a 10,000-square-foot warehouse at $65,000 – $90,000. Modified bitumen systems run slightly less upfront, $5.25 – $7.50 per square foot, but don’t carry the same cool-roof compliance benefits.
What moves the number? Layers of old roofing that must be torn off, whether a structural load evaluation flags reinforcing, how many penetrations need flashing, and how much of the work is on a shared wall. We give you a free, written estimate with every line item priced before work starts. Call (743) 200-8347 to schedule yours.
We Also Serve Cities Near Commerce
Mercer Roofing’s crews serve Commerce and the surrounding LA basin communities daily, including Los Angeles, San Diego, San Jose, and San Francisco. If your commercial property sits just outside Commerce proper, give us a call and we’ll tell you exactly how our scheduling works for your building. For more on our full service area, see Roof Installation.
Serving Commerce, CA - Our Local Coverage Area
We’re based in the Commerce 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 Commerce
Most Commerce projects require a full tearoff, not an overlay. The reason is simple: decades of Building Standard allow re-roofs without tearing off the old system, most of the flat roofs here have two to four layers of old modified bitumen or BUR stacked up, and the structural load is at or over the deck’s designed capacity. Overlaying also traps moisture between layers and voids most manufacturer warranties. We’ll tell you after an inspection, but expect a tearoff recommendation on most Commerce buildings. Call (743) 200-8347 for an exact determination.
For most 1950s Commerce warehouses, a fully adhered TPO membrane over tapered insulation is the best system. It’s reflective, meets Title 24 cool-roof requirements, and the tapered insulation fixes the low-slope ponding that old BUR roofs develop. If the structure can’t support the tearoff weight temporarily, we work with a local structural consultant to phase the job safely.
We schedule material deliveries in time slots, not all at once. The dumpster goes onto private property whenever possible, never in the street. Our crew parks in a designated area we agree on with you before the first day, and we keep all debris containers covered at end of day. These details go into your written job plan so city nuisance complaints and stop-work orders don’t slow the project.
One square equals 100 square feet of roof surface. So a 140-square roof is 14,000 square feet. That squares number is what we use to price materials and labor on your quote. If you see a different square count between two bids, one bid may be measuring the roof incorrectly. We’ll walk you through our measurement on the estimate.
Yes, if the roof ties into a shared party wall, we notify the adjoining property owner before work begins. It’s both the legal obligation and the practical way to avoid a dispute when we install flashing against their wall. We document the wall’s condition, give written notice, and get any access agreement signed before the tearoff. Call (743) 200-8347 and we’ll explain exactly what your property requires.
Call Mercer Roofing for Your Commerce Roof Installation Estimate
You’ll get a written price before any work starts, a technician whose name and photo you’ve seen before they arrive, and a 365-Day Done Right Promise in writing. If your Commerce roof is leaking, ponding, or just decades overdue for a tearoff, call (743) 200-8347 now. A live person answers, day or night, and the estimate is free.
Written by Grant Whitlock, Owner at Mercer Roofing, serving Commerce and the surrounding LA basin.