Reasons for Damage to Structural
Glass
Although
deterioration of pigmented structural glass itself is rare or unheard
of, failure of the mechanical support system which bonds the glass modules
to the wall is almost always the cause of failure, cracking, slipping,
or loss. 
Damage
is usually attributable to one or a combination of the following:
- Deterioration of the Joint Cenemt
- Hardening and Failure of the Mastic Adhesive
- Impact Due to Accident/ Vandalism
Deterioration
of the Joint Cement
Historically,
the cement joint between glass panels was intended to provide an integrated,
watertight surface. Unfortunately,
the
traditional joint cement did not possess a long lifespan. Cracked or open
joints have been the consequence, usually resulting from improper original
application of the cement or from the normal thermal expansion and contraction
cycle associated with weathering.
Cracked
or open cement joints then accelerate deterioration of the masonry substrate
and/or the mastic adhesive bond by allowing water to penetrate the internal
system. Water entering the system weakens the bond between the mastic
and the masonry substrate or rusted the anchoring shelves. This causes
the individual glass panels to gradually slip away from their original
positions and fall.

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