How Transite & Asbestos-Laden Roof Systems Have Remained Hidden

On a sunny day in Southeast IN, we had a scheduled meeting with two product engineers at a multi-metallurgical manufacturing facility. Try saying that five times in a row!? I’m a commercial roof specialist and it’s my company’s job to conduct roof analyses for large industrial buildings with aggressive environments. We assess their needs and help determine the best way to safely secure their roof and ultimately, the production space underneath.

The meeting began just like hundreds of others before it; a complementary cup of coffee, a few quips and we were off. About two minutes in, I said something that made both gentlemen, each over six feet tall, abruptly back away from me with jaws dropped in disbelief. It can be alarming to learn your entire facility’s roof system is composed of asbestos and other banned chemicals like polychlorinated biphenyls (PCBs).

I’ve been in commercial roofing for over 40 years. One of the most useful things I’ve learned in that time is how to identify and safely restore outdated, but still useful, roof systems that history seems to have forgotten. A lot of information about our previously poor decisions in construction material ingredients isn’t readily available to the average consumer or business owner. So it’s no surprise to see folks are concerned after learning about the toxic material that’s been over their heads for decades.

Roofing isn’t a romantic job. In fact, it’s commonly the first building asset to be overlooked until there’s an immediate need to be addressed, like a leak. In that same regard, repairs are often carried out with little attention to detail other than stopping a leak. This gives rise to the most common reason for building owners’ surprise to learn about their hazardous roof – oftentimes because it had been previously “repaired” or covered with a conventional roof-in-a-box product.? Standard white coatings, spray foam, and even paint have kept many of these systems hidden for a long time.? Too long.

Conventional Roofing Solutions Shouldn't be Considered for Transite/ Asbestos-Laden Roof Systems

Conventional roofing solutions work well for traditional flat roof applications. However, when the roof in question is composed of unconventional material, as is the case with transite, a specialized and custom multi-layered solution is the best alternative to a tear-off. A few characteristics of transite panels automatically disqualify most of what we consider conventional roof systems as viable solutions for re-covering outdated asbestos-laden material.

The Asbestos National Emission Standards for Hazardous Air Pollutants (NESHAP) classifies asbestos-containing materials, such as transite, a Category II non-friable asbestos-containing cement material. It holds that classification as long as the material cannot be crumbled, pulverized, or reduced to powder by hand pressure when dry. This classification holds up well when the panels were initially sold between 1930 and 1985. However, now that significant time has passed since then, businesses still operating in buildings with these roof systems are faced with an immediate need to either tear off or re-cover. Transite roofs need to be addressed today because the panels are nearing the end of their intended lifespan. They are now old, tattered, and have been weathering for years. This fact alone increases the health risks of exposure to asbestos fibers for anyone working under the roof or simply near the building.

Important Characteristics for Consideration

A frequently cited reason transite roofs are in immediate need of remediation is their age. The product went into production in the late 1920s and was produced until the early 1980s. Any roof installed somewhere in those 50+ years and still intact has experienced decades of weathering, damage, broken pieces, retrofitting, and lots of use. Many are certainly in poor condition and prone to leaking due to other contributing factors, including the effects of the industrial environment they house.??

As a Regulated Asbestos-Containing Material (RACM), OSHA and the EPA have strict protocols for working with the material if it has a high chance of becoming crumbled, pulverized, or reduced to powder. However, building owners have another option to remediate, re-cover and strengthen their old transite roofs and continue to reap the benefits of the since outlawed material. Transite is still a very useful roof system for manufacturing facilities with aggressive environments.??

Many?roof-in-a-box?products are marketed as a simple solution to cover old failing roof systems. But using conventional solutions like these is a mistake when addressing transite. This article focuses on what makes conventional roofing solutions inappropriate for re-covering existing transite and other asbestos-laden roof systems.

Silicone Roofing Solutions

Any roofing system that absorbs and disburses moisture will be a non-starter for Silicone roofing products.

Transite is a majority mixture of concrete and asbestos. It’s already a porous material that naturally absorbs and disburses moisture as needed. Silicone solutions won’t be able to stay adhered to cement for the same reason we don’t use silicone to repair bridges and roads. The result of trying to seal any cement material with silicone is that the moisture trying to escape will effectively delaminate the silicone, leaving you with the same cracks and leaks.

Moreover, once the silicone is delaminated, the building owner will be responsible for appropriately disposing of the newly disregarded silicone system with embedded asbestos fibers on the underside. Factor in the reality that the material is already compromised, being over 50 years old, and then understand that the silicone won’t be able to adhere directly to the substrate.?

Retrofit Sub-Framing Systems

Retrofit sub-framing systems should not be considered as a solution to re-cover transite asbestos roofs because anything requiring new penetrations will create?friable?material. The term friable refers to when the material is easily crumbled and the mineral fibers are readily disbursed into the air. New penetration points effectively destabilize the cement matrix of the panels and further crumble the already aging material. A retrofit sub-framing system requires installing new sub-purlins on top of the existing substrate. Not to mention, the added weight from additional purlins would not be a wise choice for the already weakening material. That’s the first reason you can’t put a retrofit sub-framing system on asbestos-cement panels.

Furthermore, a retrofit sub-framing system leaves gaps and spaces between itself and the old substrate. In the case of transite, the main issue is the occurrence of readily available asbestos fibers that can travel through the air and put employees at risk. Any roof system that doesn’t address and mitigate the possible asbestos fibers and contain them will be a red flag for both OSHA and your employees. Move on.

Single Membrane Roofing Systems?

Single-ply membranes work well for flat roofs. But old transite roof panels have a corrugated profile and an extra wide rib pattern. With popular single-ply membrane solutions like TPO, EPDM, and PVC, there’s no way to make the material adhere directly to the substrate without leaving gaps. To make the solution flush with the rib profile, extra material(s) like flute filler or other fill substitutes must be added. It’s not a good idea to add more weight to an already heavy and failing roof system. Depending on the length, asbestos-laden roofing panels can weigh up to 70 lbs each.

But even more so, whatever solution you choose must deal directly with sealing any possible asbestos fibers. Single-ply membranes don’t offer any sealing potential to contain possible loose asbestos material. Another aspect that exempts single-ply membranes from covering asbestos-laden roof panels is the necessity of adding new fasteners directly to the substrate.

Spray Foam Roofing Solutions

Spray foam roofing might seem like a viable solution at first. It’s lightweight and has the ability to adhere directly to the substrate while filling the corrugation profile. However, the results of covering transite with this roofing solution are similar to using a silicone-based product on a cement roof. It will delaminate itself once overwhelmed by moisture or vapor because transite as a substrate cannot be appropriately prepped as other non-toxic substrates can. It’s common practice to prepare a surface and clean it of debris by spray washing or stiff brooming. You can’t do that with transite for fear of disturbing any loose asbestos material. Spray foaming on transite will become delaminated much faster because the surface cannot be adequately cleared and prepared safely.

One final note is that spray foam is available in open-cell and closed-cell variations. Both variants can hold moisture and add weight. This means the foam isn’t a solid barrier as it expands. The foam is filled with hundreds of thousands of air pockets. The air pockets will eventually collapse over time as the moisture escaping the cement will get trapped within the cell structure of the spray foam.

Metal Panels

As previously stated in this article, any roof system that adds additional penetrations to an asbestos-laden roof system is a bad idea. It is unsafe to continue introducing new penetrations to the panel’s cement matrix. New penetrations effectively disturb and weaken the integrity of the panel structure, making it more susceptible to failure and producing friable material. Another danger posed by adding metal panels to a transite roof arises from the real-world knowledge of what is commonly stored underneath the roof.

Historically, as asbestos-laden roof systems were used to house artillery on military bases, the addition of metal to the roof would increase the likelihood of lightning strikes. The use of a non-conductive product across these roofs could be a matter of life and death.

While it’s not uncommon to see transite roofs that have been improperly retrofitted with metal panels, this is likely the case due to the lack of available information about the product and, to a lesser degree – the lack of education about the dangers of disturbing the material to release asbestos fibers into the environment.

Bringing It All Together

So what does work when it comes to re-covering an asbestos-laden roof and retaining the exceptional fireproofing benefits? The reality is these roof systems can still benefit the buildings they were installed on years ago. In fact, with the right kind of renewable solution, there’s no reason that existing transite roofs couldn’t remain effective for decades to come. Thermal-Tec pioneered its commercial roofing solution 40 years ago, and it remains the best renewable alternative to tearing off and relocating the material to a designated landfill. The success is in the intent of the MR Multi-Ply? Roofing Solution using renewable materials and their combined capabilities to re-cover, re-strengthen, and re-claim a leak-free environment. If you have a transite or asbestos-laden roof, contact Thermal-Tec today.?

By Robert Siterlet

President at Thermal-Tec