Ontario Roof Pros provides professional flat & low-slope roof systems in Ontario, CA for residential and commercial properties across the Inland Empire. A low-slope roof is a drainage plane with a waterproof skin, in that order. Get the fall right and almost any decent membrane performs. Get it wrong and the best membrane sold simply holds the puddle more neatly than the last one did.
Fall is built with tapered polyisocyanurate: a quarter inch per foot toward the drains, crickets between drains and behind curbs, and sumps at the bowls so the last half inch actually leaves the roof. On a re-roof, that taper layout is the part of the drawing worth arguing about, and it is the part most bids leave out because it is easier to quote flat insulation and hope for the best.
Membranes have real differences. TPO welds fast, prices well and dominates new warehouse work. PVC with a KEE plasticizer is what we specify where kitchen grease or solvent exhaust lands on the surface, because TPO does not enjoy either. EPDM stays flexible on small complicated roofs full of penetrations. Two-ply SBS modified bitumen in cold adhesive takes constant foot traffic better than any single-ply.
Under the membrane, a half-inch high-density cover board is the cheapest durability available. It stops fastener plates telegraphing through, resists hail and dropped tools, gives every weld a firm backing, and improves the fire and wind listings of the whole assembly. Leaving it out saves a little money on the bid and shortens the roof by years, which is why we price it as standard rather than as an upgrade.
Houses have these roofs too: flat additions, second-storey decks, patio covers tied into a pitched main roof. Those transitions are where most residential low-slope leaks live, so we run the membrane up under the shingle course with a proper metal transition instead of stopping it at a bead of sealant and calling the detail finished. Parapet walls get the same treatment at the coping.
Whatever system we recommend, thickness and fastening pattern come from the wind zone and the deck type rather than from a price list, and both are written on the proposal you sign. If a competing bid does not name the mil thickness, the insulation R-value and the attachment pattern, you are not comparing the same roof and the cheaper number is usually hiding thinner membrane, less insulation or fewer fasteners per square.
Our licensed and insured team brings the right materials and equipment to every job — tapered polyisocyanurate built to a quarter-inch-per-foot fall, hot-air-welded PVC with a KEE plasticizer, tested ANSI/SPRI ES-1 edge metal and coping, two-ply SBS modified bitumen set in cold adhesive, retrofit drains sleeved into existing cast-iron leaders, walk pads routed between rooftop units — and backs the work with a written workmanship warranty. We serve Ontario and nearby communities including Chino, Chino Hills, Montclair, Upland.
What We Handle
Everything our flat & low-slope roof systems in Ontario covers
One crew, one point of contact, and the full range of flat & low-slope roof systems work in Ontario, CA. If it is on this list we do it in house rather than handing it to a subcontractor:
- flat roof
- low slope roofing
- TPO membrane
- PVC membrane
- EPDM rubber roof
- modified bitumen
- tapered insulation
- high-density cover board
- roof crickets
- flat roof repair
- flat roof replacement cost
Not sure which one describes your situation? Describe it in plain words and we will sort it out — or browse the rest of our Ontario services.
Materials, equipment and how we do flat & low-slope roof systems
The difference between flat & low-slope roof systems that lasts and flat & low-slope roof systems that gets redone in three years is almost always preparation and materials, not the finish you see on day one. We work with tapered polyisocyanurate built to a quarter-inch-per-foot fall, hot-air-welded PVC with a KEE plasticizer, tested ANSI/SPRI ES-1 edge metal and coping, two-ply SBS modified bitumen set in cold adhesive, spec them to the job instead of to the invoice, and write the material grades into the free estimate so you know exactly what you are buying.
Every Ontario job runs the same way: site walk and measurements, written scope and fixed price, protection of the surrounding area, then the work itself with a daily clean-up. Years of roofing work in the Inland Empire means we have already met whatever your property is going to throw at us — awkward access, older construction, an HOA with opinions.
Where we do flat & low-slope roof systems outside Ontario
Ontario Roof Pros covers Ontario and the surrounding communities of the Inland Empire. Crews run out to the same nearby cities every week, so an out-of-town job does not mean an out-of-town price.
- Flat & Low-Slope Roof Systems in Chino, CA — San Bernardino County, population 91,403
- Flat & Low-Slope Roof Systems in Chino Hills, CA — San Bernardino County, population 78,411
- Flat & Low-Slope Roof Systems in Montclair, CA — San Bernardino County, population 37,865
- Flat & Low-Slope Roof Systems in Upland, CA — San Bernardino County, population 79,040
- Flat & Low-Slope Roof Systems in Rialto, CA — San Bernardino County, population 104,026
- Flat & Low-Slope Roof Systems in Colton, CA — San Bernardino County, population 53,909
Start on the Ontario Roof Pros homepage for a free estimate, or call (844) 511-2320 and describe the job.
Why Ontario Chooses Ontario Roof Pros
- ✓Core cuts and moisture readings before any recommendation, so the scope is based on evidence rather than a walk-around
- ✓Warehouse and industrial work phased by roof section, with every day's area dried in before the crew leaves
- ✓Proposals name the membrane thickness, insulation, fastening pattern and edge detail, so bids can actually be compared
- ✓We quote the repair beside the replacement and recommend the cheaper one when it is the honest answer
The standards behind flat & low-slope roof systems
Quality here is not a matter of opinion — it is written down. The flat & low-slope roof systems work we do in Ontario follows published industry standards: NRCA publishes the Roofing Manual, the industry's reference for details and slope minimums, and Asphalt Roofing Manufacturers Association sets the shingle application and ventilation guidance the warranties reference. If a contractor cannot tell you which standard a detail comes from, that is worth asking about before you sign.
Every flat & low-slope roof systems project in Ontario gets the same attention, whether it is a single room or a full commercial job. We show up on schedule, keep the site clean, and stand behind the work — the estimate is free and there is no pressure.
Ready to get started? Call (844) 511-2320 for a free flat & low-slope roof systems free estimate in Ontario, or request a quote and we'll get right back to you.