Commercial Modified Bitumen Roofing in Texas, an SBS 2-Ply Replacement System

Here's the decision most property managers are actually facing when they land on this page: the flat roof has leaked more than once, the cap sheet is cracking or blistering, and every repair buys a few months before the next call comes in. Modified bitumen enters that conversation as a full-system commercial roof replacement, not another cap-sheet patch. When the asphalt has aged brittle and the seams are opening, one more coat of mastic just moves the leak a few feet over.

The reason mod-bit replaces well is the combination of a redundant two-ply build and a polymer that keeps the asphalt flexible. A modified bitumen roof is a base sheet plus a cap sheet, each a full layer of reinforced asphalt, fused into one continuous membrane. The SBS polymer worked into that asphalt lets the sheet stretch and recover as the deck expands and contracts under the Texas sun, which is exactly the movement that splits an old, unmodified roof at the seams.

Whether your roof is genuinely at that point is an assessment question, not a sales question. If the field membrane is sound and the failure is isolated to flashings, you may not owe a full replacement at all. The candidacy call, restore or recover versus tear off and rebuild, is the whole decision, and it belongs in a written assessment before a proposal. Walk through it on tear-off vs. recover.

Before you approve a modified bitumen roof, you should be able to read the three lines on the proposal that set its quality. Strip the jargon and mod-bit is a purpose-built stack of two reinforced sheets and the flashings that tie them in.

• SBS is the differentiator, and it should be named in your scope. ARP specs an SBS-modified system (SBS stands for styrene-butadiene-styrene, a rubber-like polymer blended into the asphalt). SBS gives the membrane cold-weather flexibility and elasticity that plain asphalt does not have, so the sheet flexes with the building instead of cracking. Generic mod-bit bids sometimes use APP-modified asphalt, which is a different, stiffer chemistry. Ask which polymer your bid actually specifies.
• The base sheet anchors, the cap sheet armors. The SBS-modified base sheet bonds to the deck and does the structural waterproofing. The mineral-surfaced asphalt cap sheet goes on top, and its embedded granules take the UV, the hail, and the rooftop foot traffic so the membrane below does not have to. Two full plies means redundancy: if the surface is compromised, the base is still holding water out.
• The attachment method is specified to your building, not sold as one size. Mod-bit can be torch-applied, hot-mopped in asphalt, set in cold adhesive, or self-adhered as a peel-and-stick. Each has a right use, and each has buildings it is wrong for. On an occupied building where open flame or asphalt fumes are a problem, a cold-adhesive or self-adhered system is the honest answer. We spec the method to your deck, your tenants, and your fire requirements rather than defaulting to whatever is fastest for the crew.

When I write a commercial scope, I write it from the assumption that the building owner will read the warranty in year 18 and we'll still be here to stand behind it. That shapes every material spec.

One honest note most bids skip: the polymer type, the ply build, and the attachment method are where a cheap mod-bit bid quietly cuts corners. A single-ply-thin cap over a stiff APP base will pass a walkthrough on day one and cost you years on the back end. You want a contractor who writes the SBS spec, the base-and-cap build, and the attachment method into the scope in plain terms, so the roof you pay for is the roof you get.

Mod-bit is not the right system for every low-slope roof, and the honest answer for your building comes from the assessment. But there are decks where it earns its keep over both older built-up roofing and newer single-ply.

• Buildings that want proven asphalt performance with less install disruption. Mod-bit gives you the century-tested asphalt-and-reinforcement approach of built-up roofing, but in two factory-made rolls instead of three or four field-mopped plies. Two factory-made rolls mean a faster install and less mess on your roof and in your parking lot.
• Roofs that see foot traffic and temperature swings. The mineral cap sheet takes service traffic to rooftop units better than a puncture-prone thin membrane, and the SBS polymer handles the daily expansion and contraction of a Texas roof deck without splitting. For a building with techs on the HVAC every month, that combination holds up.
• Owners weighing budget against single-ply. Mod-bit and TPO overlap in price, so the decision rarely comes down to the sticker. If you value a redundant two-ply asphalt system with a tough granulated surface, mod-bit is a strong call.

Where mod-bit is the wrong call: on a roof where a reflective white single-ply would cut cooling load enough to matter to your energy budget, on a deck with standing-water problems that need to be corrected before any membrane goes down, or where a restoration coating would honestly serve a still-sound roof for less. If the existing roof can be recovered rather than rebuilt, that is a different and often cheaper path, covered on tear-off vs. recover. Modified bitumen is one system inside ARP's full commercial roof replacement lineup, and the assessment decides which one fits your roof.

Mod-bit does not exist in a vacuum. The two systems it competes with most on a low-slope replacement are built-up roofing, its direct ancestor, and single-ply membrane. Here is the honest head-to-head.

• Mod-bit vs. built-up roofing. Modified bitumen is essentially BUR's evolution. Mod-bit keeps the same asphalt-and-reinforcement idea but adds SBS polymer for flexibility and installs in two factory-made rolls rather than many field-mopped plies. BUR answers with more redundant plies and a proven gravel surface; mod-bit gives you faster installation, better flexibility in heat and cold, and fewer layers to go wrong. The full trade-off lives on built-up roofing vs. modified bitumen.
• Mod-bit vs. single-ply. A single-ply membrane like TPO is one welded sheet, lighter and highly reflective. Mod-bit answers with two redundant asphalt plies and a granulated surface built for traffic and heat. Neither is universally better; the right answer depends on your deck, your traffic, your cooling priorities, and how long you are holding the building.

Updated August 2026, Texas market pricing. The overlap in per-square-foot pricing between mod-bit, BUR, and single-ply is real, which is exactly why the decision comes down to your building rather than the sticker: polymer type, surfacing, rooftop traffic, cooling priorities, and how much installation disruption your tenants can absorb.

Commercial modified bitumen roofing in Texas runs $7.50 to $10.00 per square foot installed, base sheet, cap sheet, and flashings together. A 10,000-square-foot roof typically lands near $98,500 to $131,500, with deck condition, drainage, prep, and roof access setting the final number.

Modified bitumen is a system decision, so it prices by area with a real sample total, not a "call for a quote."

The table below is a Texas baseline. Regional market conditions add roughly 3% to 10% depending on your area, and the final number for your building depends on the four things every commercial roof does.

Updated August 2026, Texas market pricing. That $7.50 to $10.00 per square foot covers the SBS base sheet, the mineral-surfaced cap sheet, and the flashings, plus the full ARP scope: a documented assessment with photos, a written scope before you sign, manufacturer-specified application, and a final walkthrough. The number moves with the polymer and cap sheet you specify, how much the deck and drainage need correcting before the membrane goes down, and how hard the roof is to reach and stage.

As with any commercial system, your final price depends on the existing roof condition, the deck substrate, drainage requirements, and access complexity. Every ARP commercial estimate puts the full scope in writing before a contract is signed, so there are no surprise change orders sprung on day three.

For sample totals by building size across every commercial system, and what is in and out of each estimate, see the commercial roof replacement cost guide.

Get Your Written Mod-Bit Scope and Price →

You get three steps, not a mystery. Here is how a modified bitumen replacement runs from your first call to your warranty paperwork.

1. Free assessment and written scope. We walk your roof, document the condition and any wet or failed areas with photos, and hand you a written scope: the SBS system, the base-and-cap build, the attachment method, and the flashing detail at every curb, drain, and parapet, before you sign anything.
2. Deck prep and supervised two-ply install. The deck and drainage are corrected first, then the base sheet and cap sheet are installed to manufacturer specification by the install crew we deploy and supervise under an ARP project manager. You get photo documentation at each stage.
3. Final walkthrough and warranty registration. We inspect the finished roof with you, confirm every seam, flashing, and penetration, clean the site, and register your manufacturer warranty. You end with a documented roof and a paper trail you can hand up to ownership.

When you sign a commercial replacement contract, you are not hiring a logo on a truck. You are hiring a documented process, the right manufacturer backing, and a company that will still answer the phone when a question comes up years down the line.

Commercial roofing is a 20-year relationship, not a transaction. The owners we work with know we'll be there for the maintenance call, the storm assessment, the warranty question, and the next building they acquire. That's the only way commercial work stays profitable for both sides.

• The right commercial certification. ARP Roofing is a GAF GoldElite Commercial Contractor, GAF's top commercial designation, and its umbrella explicitly covers the GAF built-up and modified bitumen systems we install under one certification. We are also an Elevate Red Shield Licensed Contractor and a UNIFLEX Premier Elite Contractor for fluid-applied restoration, and we are registered with every municipality across our Texas service areas.
• A COO who reads roofs for a living. Randal Williams is a former commercial high-rise field engineer and Xactimate expert with 15+ years in roofing and construction. He has scoped and documented more than $7 million in insurance claim work across Texas, including single commercial claims above $2 million, supporting property managers and building owners through the claims process as the contractor of record. On a modified bitumen replacement, that field-engineering eye is the difference between a roof spec'd for your building and one spec'd for the contractor's convenience.
• One point of contact. Your ARP project manager runs the schedule, coordinates the permit, and delivers photo documentation from assessment through warranty registration, alongside the father-and-son team of Randal and Preston Williams, who own ARP and sign the warranties. Your roof joins the 5,000+ Texas roofing projects ARP has completed.

Modified bitumen is one system in ARP's full commercial roofing lineup, so the same documented process backs your modified bitumen roof, your single-ply, and your coatings alike, and it starts with a documented commercial roof inspection.

Modified bitumen is a long-term replacement decision, so here is the honest read on who we serve well and who we do not.

You're probably the right fit if you...

• Manage a low-slope building with a repeatedly patched roof and want the honest replace-versus-recover answer in writing
• Want the SBS spec, the base-and-cap build, the attachment method, and the flashing schedule specified before anyone touches the roof
• Run a building with rooftop traffic and heat cycling where a flexible two-ply asphalt system genuinely earns its keep
• Need photo documentation to hand up to ownership or a board
• Want one contractor for the replacement, the maintenance, and the eventual warranty call

You're probably not the right fit if you...

• Need the lowest bid in the market above all else, a respected decision we cannot always match
• Need work to begin within 24 hours with no assessment or documentation
• Have a sound roof that would be better served by a recover or a restoration coating for less, which our assessment will tell you honestly
• Want a reflective white single-ply specifically to cut cooling load, which is a different system decision

If that is the kind of decision you want to make with real numbers in front of you, book a commercial roof assessment and we will put the scope and the pricing on paper.

• SBS-modified base sheet: styrene-butadiene-styrene polymer-modified asphalt sheet bonded to the deck; the structural waterproofing layer with cold-weather flexibility.
• Mineral-surfaced cap sheet: granulated asphalt top ply; the UV, hail, and traffic armor over the base.
• Attachment methods: torch-applied, hot-mopped, cold-adhesive, and self-adhered; specified to the building, not a single default.
• Built-up roofing (BUR): the multi-ply asphalt ancestor of mod-bit, referenced in the comparison section.
• Code two-layer cap: the repair-versus-recover roof-layer limit referenced in the FAQ.

Manufacturer Certifications:

• GAF GoldElite Commercial Contractor (umbrella cert covering GAF built-up, modified bitumen, EverGuard single-ply)
• Elevate Red Shield Licensed Contractor
• UNIFLEX Premier Elite Contractor

Industry Membership:

• BBB A+ Accredited
• CTRCA (Central Texas Roofing Contractors Association) Member