Galbestos: What is it and Why is it Dangerous?

April 19, 2016

Galbestos metal cladding was produced as a corrosion resistant metal roofing and siding panel.

The general manufacturing procedure started with a carbon steel sheet that was then hot dip galvanized. While the zinc was still molten, an asbestos felt was pressed into the surface to form a mechanical bond between the zinc and the asbestos hence the name Gal-bestos.  This strip was then impregnated with asphalt under pressure and heat.  In the resultant sheet, the asbestos fibers were completely encapsulated by the asphalt.  A final protective coating of asphalt or hot melt polyester color coating was then applied as the final weathering coat.


This Galbestos coated metal was used for a wide range of metal wall and roof applications from its introduction in 1948 until manufacture was terminated in 1979 due to environmental restriction of asbestos products. The unique coating provided a virtually indestructible product in harsh industrial environments and found extensive use among the Fortune 500 of the time. Because of its durability many installations still exist.


Asbestos monitoring tests conducted by independent agencies have shown that excessive asbestos levels were not emitted by intact Galbestos under most typical handling conditions.  It was found however that cutting with an abrasive saw did produce levels of asbestos in excess of the federally mandated limits.


In the typical aging of Galbestos, the color coat hardens and shrinks.  This causes cracks to appear in the finished coat.  At this point the asphalt / asbestos layer becomes exposed.  With continued weathering the asphalt deteriorates and can erode from the panels.  In some cases the shrinkage of the Galbestos color coat can be excessive and larger areas of the asphalt / asbestos layer is exposed.


Galbestos can, however, be recoated and the heavy gauges used in industrial applications make the product an ideal candidate for restoration versus replacement.  Since the asbestos in Galbestos is encapsulated in the asphalt it is not released into the environment as free asbestos unless the asphalt is destroyed or severely weathered.


StructureTec has developed specifications to guide the safe preparation of Galbestos for restoration. Since many applications will have been previously painted our evaluation will also involve analysis of the make-up and existing conditions prior to arriving at a final system for restoration.


Since Galbestos looks so similar to other metal cladding, it is not easily identified and is often times unnoticed. We are here to help bring clarity and understanding to the many considerations available to you and how they can connect with your facility goals and objectives. If maintained and managed properly Galbestos can be protected and restored. However, if it is left to deteriorate it can become a major asbestos abatement project. StructureTec can help you determine the best course of action for managing this situation.



StructureTec is a building  envelope, pavement, and roof consultant specializing in the waterproofing and restoration of existing building envelopes, roofs, pavement and concrete structures.


Phone: 800-745-7832


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