Alternative Solution for Asbestos Roofing

Staff Report

Although the majority of roof systems are destined for landfills, this doesn’t have to be the case. By re-covering an existing roof system—no demolition required—a client retains the initial roof investment and intended functionality; the entire building structure is strengthened from the additional tensile strength of the system; and thousands of pounds of roofing material remain in use and out of landfills, according to Thermal-Tec President, Robert Siterlet.

One such example of a successful—yet complicated—roof re-cover is AFS Corporate Member Atlas Foundry Co. Established in 1893, the business produces gray iron castings for the agriculture, construction, transportation, and manufacturing industries. Foundry facilities are built to withstand intense processing heat loads because of the high temperatures of furnaces and other equipment used in the material processing.

Atlas Foundry’s 90,000-sq.ft. Marion, Indiana, facility was built in 1958—a time when a new Chevy Bel Air cost $1,987 and asbestos-laden products were all the rage. Asbestos had long been praised for its heat-resistant properties and durability. Naturally, it was widely accepted as a necessary additive to strengthen the performance and durability of construction products, especially roofing panels. After 63 years of use, the Marion facility’s transite—an asbestos-laden, cement-board material—roof was cracking and allowing moisture into the building, which is a serious problem for a foundry.

The client needed a solution that would withstand the high temperatures generated by the foundry’s equipment and processing, as well as ensure the foundry’s production would remain on schedule. Working on a transite roof created additional challenges for the roofing team to consider.

Transite History

Transite was officially banned from production in 1985 after the public became aware of the health-related effects from long-term exposure to asbestos. In fact, during the heyday of manufacturing construction materials with asbestos, manufacturer spec sheets list many construction products as containing no less than 45% asbestos by weight. 

Fireproofing aside, the longevity of a transite roof was an estimated 50 to 70 years. That aspect alone positioned transite products as a must-have roof system for a multitude of manufacturing facilities built in the U.S. between 1930 and 1980. To this day, hundreds (if not thousands) of original transite roofs are still protecting chemical plants, paper mills, textile factories, and foundries.

Asbestos removal is extremely expensive and dangerous and, therefore, regulated by the EPA and OSHA. In addition, transite panels are heavy, weighing anywhere from 50 to 60 lbs. for a typical 12-ft.-long roof panel. It also costs a small fortune to transport the material to a specially designated landfill for hazardous waste. Many building owners choose to abandon buildings with transite roofs rather than consider other options.

Challenges Abound

There were many challenges with Atlas Foundry’s re-cover project. For one, the Marion facility’s structural integrity was a concern. Withstanding weather for more than 60 years contributes to the traditional wear and tear of a building structure (think annual thermal expansion and contraction).

The moisture leaking into the facility not only can introduce contaminants into production, which compromises product integrity, a simple drop of water in the wrong place can cause a catastrophic explosion.

The chemical processing that takes place at Atlas Foundry produces significant amounts of sulfur and other vapors. The years of chemical offgassing had all but decommissioned the fiberglass skylight panels, leaving a safety hazard. The skylights had served as a light source in the event of a power outage. They’re mathematically engineered to cast light in a series of lines, leading the way to exits. The old skylight panels would have to be removed and replaced.

Because the facility is located in a residential neighborhood, the client decided a roof restoration would be safest. Tearing off a transite roof could release millions of tiny asbestos fibers into the air.

The Re-cover

The restoration process seals the hazardous transite material tightly while adding 80,000 to 100,000 lbs. of tensile strength to the roof.

The system begins with a primary layer of specially formulated asphalt that is sprayed directly onto the transite panels, followed by the application of a polyester membrane along the sprayed path. After the membrane is in place, crew members “broom down” the membrane so it adheres directly to the transite.

Once the section has been broomed down, the sprayer returns to apply another topcoat of specially formulated asphalt to seal in the membrane. Seams of the membrane are effectively sealed underneath the second layer of asphalt, making it seam-free.
The asphalt in this first phase is then left to cure for four to six weeks and solidify. Once cured, the crew returns to apply a fresh layer of the asphalt followed immediately with an application of recycled, carbon-based roofing granule. The granules are embedded into the asphalt. This top layer of asphalt cures with the granules in place. The multi-layer system becomes a seamless, monolithic wrap that can flex with the building while keeping the transite intact, thanks to the added tensile strength.

Adding just 12-14 ounces per sq.ft. to the structure, the foundry had no issues supporting the weight of the new roof system. Now, the top surface will be renewed every 10-15 years with a fresh layer of asphalt and additional granules.

Thermal-Tec serves as environmental stewards by offering companies––including manufacturers––an alternative to discarding old asbestos-laden roof systems into landfills. Re-covering a transite roof not only protects the people working at the facility, it protects the business itself by saving usable floor space without having to shut down operations. The business also retains the fire-resistant properties of the original transite roof.