Roofing Flux

By: Z. Wiley

Edited by: Siyana Randolph

Roofing flux is a petroleum-based asphalt used almost exclusively in the construction of roofs for industrial, commercial, and residential buildings. It is primarily manufactured by Irving Oil, a company based in Saint John, Canada, that specializes in gasoline, oil, and natural gas products. The roofing flux imported into the United States originates at Irving Oil’s main refinery in Saint John. In addition to Irving, Bitumar Incorporated—headquartered in Montreal, Canada, with a major facility in Baltimore—imports roofing flux for production and distribution across the United States and Canada. Together, these two firms dominate the North American roofing-flux trade and maintain a steady flow of product through the Port of Baltimore.

Import Quantities to the Port of Baltimore:

According to the ImportInfo database, fifteen shipments of roofing flux were processed through the Port of Baltimore during calendar year 2024. These shipments totaled 126,644.55 tons. This means Baltimore received an average of approximately 10,553.7 tons per month in 2024. Of the fifteen total shipments, twelve were delivered to Bitumar Inc. and three to Irving Oil. Baltimore led the United States in roofing-flux imports, followed by the Ports of Wilmington, NC, and Providence, RI. Nationwide 328,984.8 tons of roofing flux were imported across 42 shipments. The Port of Baltimore accounted for approximately 38% of the total national volume and 36% of total shipments, underscoring its dominant role in this specialized commodity sector.

Workers applying roofing flux (CDC)

Composition and Uses:

Roofing flux is a softer, higher-penetration asphalt compared to standard paving asphalt, according to research published in Asphalt Magazine. Its composition makes it ideal as a base for asphalt shingles and as an insulating material for both residential and commercial roofs. In manufacturing, roofing flux can be solidified and rolled into sheets that are heat-applied to roof surfaces, forming durable, weather-resistant membranes. The material’s flexibility, water resistance, and adhesion properties make it essential in both flat and sloped roofing systems, particularly in regions with significant temperature variation.

Transport:

Due to its sticky, viscous nature and its tendency to harden even at high temperatures, roofing flux must be transported in molten form between 482°F and 572°F. This requires specialized break-bulk carrier ships fitted with tanks capable of maintaining these extreme temperatures throughout the voyage. As noted by Marine Insight, these tanks include layers of synthetic and mineral insulation to minimize heat loss during transport. Upon arrival at port, the molten bitumen is pumped from the vessel using insulated discharge pipes, then transferred to heated onshore storage facilities before being processed or distributed. This technically complex process underscores the Port of Baltimore’s ability to handle high-temperature bulk commodities safely and efficiently.

Trade Relationships and Distribution:

Canada serves as the principal exporter of roofing flux to the United States, with major production centered in Saint John and Montreal. Irving Oil’s refinery operations and Bitumar’s dual Canadian–U.S. presence form the core of this trade. Bitumar’s Baltimore facility plays a vital role as both importer and regional distributor, linking Canadian producers to American construction and roofing markets. Once refined and processed locally, roofing flux is transported by tanker truck or rail to roofing manufacturers and contractors across the Northeast and Mid-Atlantic. This flow of material supports ongoing construction and infrastructure development throughout the region.

Roofing flux is an essential industrial product that links Canada’s petroleum-refining sector to U.S. construction markets through the Port of Baltimore. Its physical characteristics demand complex logistics, including high-temperature transport and specialized handling facilities. Baltimore’s leadership in roofing-flux imports represents over one-third of all U.S. shipments, demonstrating the port’s strategic value in managing energy-based construction commodities. From Canadian refineries to American rooftops, roofing flux illustrates the interdependence of North American energy production, infrastructure, and maritime commerce.