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C.05 · Commercial roofing

Modified bitumen roofing for Tulsa commercial properties.

Modified bitumen is what you specify when a single-ply membrane is not enough. Two reinforced plies, torch-applied cap sheet, and a track record on Oklahoma commercial buildings that goes back decades. The right system for complex roofs, heavy equipment, and buildings that see real foot traffic.

APP and SBS systemsTwo-ply reinforcedTorch or cold-applied20-year warranty

Q: What is modified bitumen roofing and when is it the right choice?

A: Modified bitumen is an asphalt-based roofing system reinforced with polyester or fiberglass and modified with either APP or SBS polymers for improved flexibility and durability. It is installed in two plies: a base sheet and a cap sheet. It is the right choice for buildings with significant rooftop foot traffic, complex geometry, existing BUR systems being replaced in kind, or any application where a reinforced two-ply system is specified over a single-ply membrane.

Modified bitumen sits between single-ply membranes and full built-up roofing in terms of complexity and performance. It offers more puncture resistance and foot-traffic durability than TPO or EPDM, with a simpler installation process than multi-ply built-up roofing.

In the Tulsa commercial market, modified bitumen is common on older retail buildings, light industrial facilities, and any building that originally had a BUR system and is replacing it in kind. Architects and property engineers also specify it when the building profile, rooftop equipment density, or maintenance requirements call for a reinforced two-ply system.

Oklahoma's temperature range is a real consideration. A rooftop that goes from 10 degrees in January to 110-degree surface temps in July puts stress on any membrane. SBS-modified bitumen handles that thermal cycling better than APP on most commercial buildings, though APP is more UV-resistant for buildings with exposed southern exposures. We will specify which modifier is right for your building after we inspect it.

Time for modified bitumen

Signs your building is right for mod-bit.

Modified bitumen is often the right spec when single-ply is not enough. These are the scenarios where it makes sense.
01

Existing BUR roof at end-of-life

If your building has an aging built-up roof, modified bitumen is the natural modern replacement. It installs faster than BUR, carries better warranty terms, and handles similar applications.

02

Heavy rooftop equipment

Buildings with dense HVAC, mechanical equipment, or rooftop curbs require a membrane that handles foot traffic from installation and service crews without puncturing.

03

Complex roof geometry

Multiple elevations, parapets, drains in various locations, and intricate flashing details are where two-ply reinforced systems outperform single-ply on long-term waterproofing.

04

Low-slope roof with drainage challenges

Modified bitumen with a torch-applied cap handles standing water better than some single-ply membranes on low-slope applications with marginal drainage.

05

Specified by architect or engineer

Some commercial projects, new construction and renovation alike, carry a modified bitumen specification from the design team. We install to spec and meet with the architect during install when required.

06

Repair patches failing on existing mod-bit

When patches on an existing modified bitumen roof are no longer holding, it is time to evaluate the full system condition. Often one to two sections are failing while the rest of the field is sound.

Our mod-bit install process

Four steps from inspection to warranty card.

Modified bitumen installs are more detailed than single-ply. Every step is documented and supervised.

01/04

Inspect and core-cut

Full roof walk with photos of every deficiency. Core cuts at field locations and near penetrations to check substrate moisture and insulation condition. Written report within 48 hours.

Free / same week
02/04

Spec and bid

We specify APP or SBS based on building exposure, roof geometry, and maintenance needs. Itemized bid covers base sheet, cap sheet, insulation, flashings, and any substrate work. Two-ply systems have more line items than single-ply; every line is visible.

48-hr turnaround
03/04

Install

Base sheet installed and mechanically fastened. Cap sheet torch-applied or cold-adhered to manufacturer specification. All penetration flashings built to two-ply detail. Drainage checked at every stage. Daily progress photos to your PM.

1 to 3 weeks
04/04

Warranty and maintenance

Manufacturer warranty registered in your name. Close-out packet with material documentation and warranty terms. Bi-annual maintenance plan available to audit lap seams, drain collars, and flashing conditions.

20-yr warranty
System types and materials

APP vs. SBS and what drives the choice.

We install modified bitumen from Carlisle, GAF, and Firestone. Base sheets are fiberglass or polyester-reinforced. Cap sheets are selected based on exposure and application.

APP modified bitumen is torch-applied and handles UV radiation and high-surface-temperature applications well. Better choice for south-facing, sun-exposed roofs in Tulsa where summer surface temperatures are the primary stress factor. APP cap sheets with granule surfacing also provide good hail resistance.

SBS modified bitumen uses a rubber modifier that maintains flexibility at low temperatures. Oklahoma winters that drop below freezing and produce rapid freeze-thaw cycles are harder on APP than on SBS. For buildings in northern Tulsa suburbs like Owasso and Claremore where winters are harsher, SBS is often the better long-term spec.

Cold-applied systems use adhesive rather than open flame. Required on some occupied buildings or properties with fire suppression restrictions. Performance is equivalent to torch-applied when installed correctly, but application conditions and adhesive temperature matter more. We specify and manage those conditions carefully.

Cost considerations

What drives modified bitumen cost.

Modified bitumen costs more to install per square foot than EPDM and is typically comparable to or slightly more than TPO, depending on building complexity. The two-ply system requires more material and more labor than single-ply membranes. That cost buys you a reinforced system with better puncture resistance and traffic tolerance.

Substrate condition is the biggest variable in the bid. Buildings replacing existing BUR systems often find that the old insulation is in acceptable condition and can be recovered over, which saves significant tear-off cost. Buildings with wet or degraded insulation need full substrate replacement, which adds material and labor.

Flashing complexity also drives cost on modified bitumen. Two-ply systems require more detailed flashing work at every penetration, parapet, and drain than single-ply installs. On buildings with complex geometry, that flashing work can add 15 to 25 percent to the total installed cost. We itemize every flashing detail in the bid so you see the full picture before signing anything.

Two-ply reinforced. Built for Oklahoma conditions.

(918) 978-2660Talk to a commercial project managerRequest a commercial bid
Why AE Roofing for modified bitumen

Torch work requires trained hands.

Torch-applied modified bitumen is not a job for a crew that occasionally does flat roofing on the side. Open-flame application requires crew members who understand heat saturation, lap detail, and drainage slope. Undertorched laps fail at seams. Overtorched membrane blisters and loses structural integrity.

Our commercial foremen are certified on modified bitumen installation and hold OSHA 30 credentials. Every torch-applied install uses a trained foreman running quality control behind the crew, not just a supervisor watching from the ground.

After installation, every modified bitumen project gets the same close-out documentation as any other commercial system: warranty registration in your name, material specs, and photos. We also offer a bi-annual maintenance plan that audits lap seams and drain details twice a year, specifically the areas where mod-bit systems develop issues over time.

Service area

We install modified bitumen across Tulsa and these surrounding cities:

Broken ArrowCoverage
OwassoCoverage
BixbyCoverage
JenksCoverage
Sand SpringsCoverage
SapulpaCoverage
ClaremoreCoverage
CatoosaCoverage
Modified bitumen FAQ

Questions before
the bid.

Not on the list? Call us. A human picks up. Usually on the second ring.

Ask us directly
A two-ply modified bitumen system properly installed in Oklahoma typically lasts 20 years or more. APP cap sheets handle UV well. SBS systems handle cold-temperature flexibility well. Both tolerate Oklahoma's temperature swings better than single-ply EPDM on larger commercial buildings with significant thermal movement.
APP (Atactic Polypropylene) is torch-applied and handles UV exposure and heat better. It is the right choice for buildings where the roof surface gets intense summer sun. SBS (Styrene Butadiene Styrene) uses a rubber modifier that gives the membrane more flexibility at low temperatures. For Tulsa buildings that see hard temperature swings, SBS is often the preferred cap sheet.
Modified bitumen and TPO serve different applications. Modified bitumen is a two-ply reinforced system that handles foot traffic, slopes, and rooftop equipment well. TPO is a single-ply membrane with better energy performance and lower cost on simple flat builds. For buildings with complex geometry, equipment-heavy roofs, or existing BUR systems being replaced in kind, modified bitumen is often the better choice.
Sometimes. A modified bitumen cover board system can be installed over an existing built-up roof if the existing plies are sound and the insulation is dry. This saves tear-off cost and keeps existing insulation R-value. Core cuts during inspection tell us whether the substrate will support a recover.
We use both, depending on application. Torch-applied APP is the standard for most commercial mod-bit installs in Tulsa. Cold-applied systems using adhesive are used where open-flame work is restricted, such as occupied facilities with fire suppression concerns or buildings near sensitive equipment.
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