Modified Bitumen Roofing in Orlando, FL

Service

When Modified Bitumen Is the Right Specification in Orlando

BUR recover path: A significant share of Central Florida's 1970s and 1980s commercial building stock was originally roofed with BUR (built-up roofing) — alternating layers of felts embedded in hot asphalt. Some of that BUR is in good condition other than the cap sheet, and recovering with a modified bitumen cap ply is the most economical path — avoids tear-off cost, disposal cost, and disruption, while adding a new waterproof cap layer with a 10-to-15-year life. We assess every existing BUR system for recover eligibility before recommending tear-off. The Downtown Orlando office building stock around Lake Eola and the Winter Park historic commercial district both have BUR inventories where recover is often the honest answer.

High-traffic roofs: Modified bitumen's multi-ply construction provides impact resistance that single-ply membranes cannot match. Buildings with dense rooftop HVAC equipment, frequent maintenance trades on the roof, and a history of puncture damage are often better served by modified bitumen's redundant layers than by a 60-mil single-ply. Sanford and Lake Mary commercial buildings in light-industrial use, with rooftop air handlers that require quarterly HVAC service, are typical candidates.

Buildings with complex drainage geometry: Modified bitumen's self-adhered base sheet and torch-welded cap sheet can be detailed around complex roof geometry — multiple level changes, unusual parapet configurations, buildings with equipment room hatches and access points every 50 feet — with more field flexibility than rigid single-ply systems. The Disney Springs and Lake Buena Vista entertainment complex buildings, some of which have highly non-standard roof geometry from architectural intent, are cases where modified bitumen's field fabrication flexibility is an advantage.

Budget-constrained shorter-capital-horizon decisions: Modified bitumen installed over a dry existing system at the recover-eligible threshold can be a 10-to-15-year capital decision at a lower installed cost than full TPO replacement. For building owners who are planning to sell or redevelop a property within that horizon, a modified bitumen recover can be the defensible economic choice.

Installation Methods and Fire Safety in Orlando

Torch-applied modified bitumen uses an open-flame propane torch to heat the underside of the cap ply until the factory-applied asphalt is molten, then the sheet is pressed to the base layer or substrate to create an adhesive bond. This is the most common installation method for modified bitumen in the commercial market. In Orlando, hot-work permitting requirements apply — we obtain the building owner's hot-work permit before each day of torching, confirm that the fire watch is in position, and coordinate with the building's fire alarm panel to suppress nuisance-alarm trips during the work.

Cold-applied modified bitumen uses asphalt-based adhesive or asphaltic compounds to bond the sheets without open flame. This method is required in buildings where hot-work is prohibited — hospitals, occupied lab buildings, and some high-occupancy hotel properties. Cold-applied systems are more sensitive to temperature and cure time than torch-applied, and they require a longer cure period before the next layer is applied. We use cold-applied modified bitumen on Lake Nona Medical City buildings and other properties where hot-work prohibition is in force.

Self-adhered base sheets (peel-and-stick) eliminate hot-work for the base layer, requiring only torch or cold-applied for the cap ply. On buildings where reducing torch exposure time is a priority, we specify self-adhered base sheets and reserve torch application for the cap layer only. This is a common specification for occupied hotel buildings on International Drive where minimizing fire-watch duration and hot-work exposure reduces operational disruption.

Modified Bitumen Performance in Florida's Hurricane and Rainfall Environment

Modified bitumen's multi-ply construction gives it redundancy that single-ply systems lack. If the cap ply is compromised at a seam or penetration, the base ply still provides a waterproof barrier — giving time to identify and repair the cap ply failure before it becomes an interior leak. In post-hurricane inspection after Irma (2017) and Ian (2022), we found that modified bitumen field zones on well-maintained roofs consistently showed less penetration than comparable age single-ply systems in the same wind-field.

The failure mode for modified bitumen in hurricane conditions is different from single-ply: edge metal and parapet flashing separation (same as single-ply), and granule loss at the cap sheet surface (which does not immediately compromise waterproofing but does accelerate UV degradation if not addressed). We inspect every linear foot of cap-sheet surface on post-storm assessments for granule stripping and membrane cracking, and document the full surface condition in the post-storm report.

Florida's FBC wind-uplift requirements for modified bitumen systems reference FM Global and ANSI/SPRI standards. Every modified bitumen installation we specify references the FM-approved fastener patterns and attachment methods for the building's FBC wind zone and exposure category. The permit documentation includes the FM design reference and the product approval numbers for every component in the system.

Frequently asked questions