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. Contact us today!