Free roof inspection with deck photos before we talk money - GAF and Owens Corning certified installation
Before
After
Before
After
Before
AfterFast, Reliable Roofing Company Across Commerce
If you own a building in Commerce, the odds are good that your roof is flat, commercial, and decades old. Most roofing work in Commerce is not residential shingle work. It is membrane work: TPO, EPDM, or modified bitumen over postwar industrial decks that have been overlaid again and again. Mercer Roofing handles that reality every day, and we handle it with a written price before any work starts. Call (743) 200-8347 to schedule a free estimate, and we will send a background-checked, photo-badged technician whose name and photo you receive before they arrive.
Why Mercer Roofing Is Commerce’s Preferred Roofing Company
Commerce is not a typical roofing market. The city is dominated by single-story warehouses, distribution centers, and manufacturing plants between the I-5 and SR-60, and that changes the kind of roofing contractor you need. Our crews work on Class A commercial flat-roof systems constantly: TPO, EPDM, modified bitumen, and built-up roofing. We know what the Los Angeles office coordinates and what gets dispatched to Commerce, and we schedule based on real access hours at industrial parks and loading docks, not on residential assumptions. Call us at (743) 200-8347 and a live person answers, 24/7.
Every technician we send to Commerce is background-checked, identity-verified, and photo-badged under the Threshold Verified standard. That matters when you are opening a facility gate or letting someone onto a commercial roof at 6 a.m. The Roofing Company team at Mercer Roofing is part of the Threshold Group family, founded in 2000. Grant Whitlock leads our operations, and the standard he enforces is simple: your written price comes first, your written guarantee is included on every repair, and the person at your door is the person whose name and photo you already have.
Roof Maintenance in Commerce
Roof maintenance in Commerce means proactive flat-roof care: clearing drains and scuppers, inspecting seams and flashings, checking for ponding water, and recoating or resealing problem areas before a leak becomes a full reroof. In a city this industrial, roof maintenance is not optional. A blocked drain on a flat commercial roof during a winter storm is a fast route to membrane damage and interior water intrusion. For most Commerce buildings, a maintenance visit with minor repairs runs $350 to $900 depending on roof size and condition. Larger warehouse roofs with extensive ponding and seam repairs run $1,200 to $2,800. We give you a written price before we touch anything.
Drainage, Ponding, and Flat-Deck Health
Flat commercial roofs in Commerce collect water by design, which means drainage is the single most important maintenance item. We inspect every drain, scupper, and overflow path, then clear debris that blocks them. Where ponding persists more than 48 hours after rain, we mark the low spots and recommend structural review of the deck, because repeated ponding accelerates membrane failure faster than anything else in this climate.
Preventive Membrane Repairs
Seams and penetrations are where flat roofs fail first. We inspect every pipe boot, vent, curb, and transition, then reseal or reinforce weak spots before they open. A small seam repair on a Commerce warehouse roof typically costs $250 to $700 and can prevent a $15,000 emergency reroof down the line.
Roof Coating in Commerce
Roof coating in Commerce is often the most cost-effective way for building owners to meet California Title 24 cool-roof requirements without a full tearoff. The urban heat island effect in the I-5/SR-60 corridor is intense: dark industrial rooftops absorb heat and push building cooling costs up. A reflective elastomeric coating or TPO membrane keeps the roof surface cooler, extends the life of the existing membrane, and brings the building into compliance. A coating project on a typical Commerce warehouse starts around $2,500 to $6,000 depending on square footage and surface prep.
Title 24 Cool-Roof Coatings
For commercial re-roofing in Commerce, a cool-roof system is not a nice-to-have. California’s energy code requires reflective roofing on most commercial buildings. We apply coatings with tested solar reflectance and thermal emittance values, and we document the compliance for your records. This is not a coating job a generalist can fake; the product has to meet the standard.
Extending an Aging Flat Roof
If your Commerce building has an older modified bitumen roof that is still sound but aging, a seamless elastomeric coating can add five to ten years of service life. We inspect for delamination and wet insulation first, because coating over trapped moisture locks in the problem. The inspection is part of the written estimate.
Trusted Brands We Service in Commerce
We install and repair roofing systems from manufacturer-recognized brands including GAF, CertainTeed, and Owens Corning, plus Atlas and Tamko for the limited residential stock in Commerce. For the flat-roof systems that dominate this city, we work with TPO and EPDM products we stock locally for Commerce projects, which means we do not lose days waiting on shipped materials. If you have a GAF or Owens Corning warranty on a Commerce building, we can handle the service work under that warranty. The written guarantee on every repair is ours, in addition to whatever the manufacturer covers.
Common Roofing Problems We See in Commerce Homes and Buildings
- Ponding water on flat warehouse roofs. Low-slope commercial decks in Commerce often have inadequate drainage, and standing water deteriorates membrane laps and seams. We locate the exact low spots and spec drainage corrections before recoating.
- Accumulated overlay layers on postwar industrial roofs. Many Commerce buildings have three or four accumulated layers of modified bitumen or BUR over the original deck. Each new overlay adds weight, and the deck may require a structural load evaluation before another system can legally and safely be added.
- Failed flashing at penetrations. Vents, curbs, skylights, and pipe boots on flat roofs take constant thermal movement. Flashing failures are the most common leak source we repair on Commerce commercial buildings, especially on the older BUR systems.
- Membrane delamination under heat. The heat island effect around the I-5/SR-60 interchange puts constant thermal stress on dark flat roofs. Over time, the membrane separates from the substrate. We test for delamination during every inspection because coating over a delaminated roof makes the failure worse.
Pricing for Roofing Company in Commerce, CA
Roof maintenance visits in Commerce run $350 to $900 for most flat commercial roofs with minor repairs. Roof coating projects start around $2,500 to $6,000 for a modest warehouse, and a full commercial reroof with TPO or modified bitumen typically lands between $8 and $14 per square foot, depending on deck condition, insulation needs, and the number of accumulated layers that have to be removed. A structural load evaluation, when required before a reroof, adds $1,500 to $3,500. We do not quote a Commerce reroof without inspecting the existing roof in person, and we never give a verbal number that becomes a different number on the invoice. The written price you approve is the price you pay. Call (743) 200-8347 for a free estimate on any Commerce building.
We Also Serve Cities Near Commerce
While this page is focused on roofing work in Commerce, our crews serve clients across the region. That includes Commerce and the surrounding industrial corridor, plus Los Angeles, San Diego, San Jose, and San Francisco. If your building sits within reach of our dispatch and you want the same written-price, photo-badged standard, we will come out and inspect it.
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 Roofing Company in Commerce
Many Commerce buildings have had successive overlays of modified bitumen or built-up roofing applied over the decades, and three or four accumulated layers are common. Each layer adds weight, and the original deck was not always designed for that load. Before we spec a new system, an engineer evaluates the existing roof assembly and deck framing. The evaluation typically costs $1,500 to $3,500 and is written into your contract as a line item. Skipping it can cause a mid-job permit halt or, worse, a deck failure. Call (743) 200-8347 and we will explain exactly what your building’s roof stack looks like.
For a low-slope or flat Commerce warehouse, TPO or EPDM membrane systems are the standard, with modified bitumen also common in the older building stock. Asphalt shingles are designed for steeper residential slopes and will not shed water properly on a low-slope industrial deck. We spec the system based on the actual roof slope, deck condition, and code requirements, and we show you the options in writing before you choose.
California’s Title 24 energy code requires cool-roof compliance on most commercial re-roofing projects, and Commerce’s dense dark-roof industrial corridor makes the heat island effect especially pronounced. We spec reflective TPO or elastomeric coatings with documented solar reflectance and thermal emittance values, then provide documentation for code enforcement. A non-compliant overlay can leave you exposed to citations and rework.
We inspect first, and we price the known scope before we start. When our crew opens an older Commerce roof or wall and finds something the original quote did not cover, undersized framing, failed waterproofing, hidden deck damage, we stop and show you what we found. Then we write the scope and cost of the fix as a written change order for your approval before we touch it. Nothing gets done on a surprise basis and nothing gets billed on a surprise basis. That is the Mercer Roofing standard, and it is why older Commerce buildings do not blow their budgets with us.
Line up the bids, then look for what each one leaves out. A bid that does not mention a structural load evaluation on an overlay-heavy Commerce roof is a bid that will change. A bid that does not confirm Title 24 cool-roof compliance is incomplete. A bid that does not list the membrane thickness, the insulation value, and the warranty term is a guess. We give you a written, line-item price with all of that in it, including the manufacturer and product name. Call (743) 200-8347 and we will walk your roof with you and give you the numbers in writing.
Commerce is a city of flat roofs, old industrial decks, and building owners who need a contractor that understands code as well as membrane. The Roofing Company team at Mercer Roofing knows what a Commerce roof stack looks like because we have opened enough of them. Grant Whitlock and our Commerce crews handle inspection, structural evaluation, and Title 24 compliance as part of the bid, not as an afterthought.
If you need roof maintenance, a coating, or a full reroof on a Commerce building, call (743) 200-8347 for a free estimate. A live person answers, 24/7, and the technician we send will arrive with a photo ID and a written price before any work starts.
Written by Grant Whitlock, Owner at Mercer Roofing, serving Commerce since 2000.