TPO · Fully Adhered
75,000 sqft Cold Storage Facility
Sqft75K
System80-mil TPO FA
Timeline10 days
SBS and APP modified bitumen multi-ply roofing systems for heavy-traffic manufacturing, mechanical roofs, retrofits over existing built-up roofing, and legacy commercial buildings across NC, SC, GA, and TN. Torch-applied, cold-applied, or self-adhered with NDL warranties up to 20 years.
A licensed PM has your request. We'll reach out within 24 business hours — typically sooner. If your roof is actively leaking, call (866) 487-8572 for same-day response.
Single-ply membranes won the commercial roofing market since the 1990s on cost and install speed. But modified bitumen never went away for specific applications — and understanding when to spec mod-bit is one of the marks of a serious commercial roofer versus a TPO-for-everything contractor.
The core advantage is thickness. A 2-ply SBS modified bitumen system is roughly 180 mils thick — three times the thickness of 60-mil TPO. A 3-ply system runs 250+ mils. For commercial buildings with heavy rooftop foot traffic — manufacturing plants with regular HVAC service rounds, food processing facilities with daily rooftop sanitization equipment, medical buildings with rooftop generators requiring weekly service — the physical robustness of modified bitumen translates directly to longer service life before puncture or impact damage. Dropped tools, hailstones, and mechanical stress that would breach a single-ply membrane don't reach structural damage on 3-ply mod-bit.
The second advantage is retrofit compatibility. Mod-bit bonds chemically to existing built-up asphalt roofs in ways single-ply cannot. For the large legacy-commercial building stock in the Southeast built with BUR in the 1960s-1980s, mod-bit is the path of least resistance — structural weight capacity allows recover over existing roof, avoiding the cost and disruption of tear-off. We've done major mod-bit retrofits on 1970s warehouses in Mecklenburg and Guilford counties where a TPO-required tear-off would have added 40% to project cost and 2-3 weeks to timeline.
Installed cost runs $9–15 per square foot for 2-ply modified bitumen with standard prep. Ranges below reflect bid data. 3-ply upgrade adds $2-3.50/sqft; cold-applied vs torch adds $0.50-1.50/sqft; retrofit over BUR deducts $2-3/sqft from tear-off cost.
Mod-bit install is more labor-intensive than single-ply and requires more fire-safety and occupancy coordination. Our process follows NRCA Multi-Ply Roofing Manual specifications and maintains separate certified crews for torch-applied versus cold-applied work.
Drone survey, moisture-probe cores (2 per 10,000 sqft), structural weight review. Modified bitumen excels as a retrofit over existing BUR where structural capacity allows — we run the weight calc first. Spec decisions: SBS vs APP per climate zone, 2-ply vs 3-ply per traffic load, torch vs cold-applied per occupancy status. Detailed bid in 48 hours.
Existing roof cleaned and repaired; damaged sections removed and patched. For new construction: insulation board to R-25 minimum for NC climate zone 4A. Base sheet mechanically attached on 9-inch to 12-inch centers per wind uplift calc. The substrate prep phase determines 70% of modified bitumen service life — we spend proportional time here.
First ply of modified bitumen applied — torch-down, cold-applied adhesive, or self-adhered per spec. Laps overlapped 3 inches minimum. Torch crews work in 2-person teams: one operator torching the roll, one fire-watch managing combustibles. Cold-applied uses squeegee adhesive troweling. Self-adhered peels release liner and pressure-rolls into place.
Intermediate ply offset 50% from base ply laps to create staggered seam pattern. Torch-welded or adhesive-bonded to base ply. This ply adds the structural redundancy that makes 3-ply worth the extra cost for industrial applications — any base-ply defect is covered by intermediate-ply overlap.
Granulated cap sheet (mineral-surfaced) installed with staggered laps offset from underlying plies. Cap sheet provides UV protection, walking surface, and architectural appearance. Laps heat-welded or adhesive-sealed per manufacturer spec. Edges detailed with metal counter-flashing and liquid sealant.
Penetration flashings fabricated from matching modified bitumen, heat-welded or hand-detailed. Wall flashings, parapet coverage, drain detailing to NRCA multi-ply manual standards. Every flashing inspected and documented. NDL manufacturer warranty registered (15-20 years). As-built drawings and maintenance schedule delivered to building owner.
Heavy-traffic industrial, manufacturing retrofit, and legacy commercial mod-bit installs completed across NC, SC, GA, TN. GAF, Siplast, CertainTeed, and JM NDL warranties registered with every job.
The Southeast has a huge stock of commercial buildings with existing built-up roofs from the 1970s and 1980s — factories, warehouses, shopping centers, office buildings that still have original BUR in service past its warranty window. For these buildings, the financial decision isn't "replace with the best new system" but "what's the NPV of retrofit versus tear-off-and-replace."
Modified bitumen retrofit over sound existing BUR typically runs 60-70% the cost of a tear-off-and-replace with single-ply. Additional advantages: no disposal cost for the existing BUR (major for buildings with bonded-gravel ballast systems where removal is expensive and messy), no structural weight reduction risk (some old commercial roofs have deflection that actually stabilizes with the existing weight load in place), and typically 2-3 weeks faster timeline.
The retrofit calculus requires structural verification — we pull the original drawings where possible, run core-sample weight calcs, and size the mod-bit spec to additional-load capacity. For owners who plan 15-20 year holds on buildings with sound existing BUR, mod-bit retrofit is almost always the right economic answer. For owners who plan to sell within 5 years, single-ply replacement often wins on buyer-perception and due-diligence clean-look — NPV conversation varies by portfolio timeline.
Heavy-traffic commercial, retrofit over BUR, or legacy building restoration. SBS or APP, 2-ply or 3-ply, torch or cold-applied. Detailed line-item bid in 48 hours.