Case 2

Introduction

Sealant Decomposition

Type of Building: Commercial Building

With the use of granite cladding panel, joint sealants employed must have the ability to deform under greater loads and stresses imposed by these bigger panels. Thus various amounts of extenders are added to the basis polymers, the most important of which are silicone oil plasticisers. In some instances, part of the silicone oils are replaced with mobile non-silicone hydrocarbon extenders and these products are more likely to cause staining of adjoining substrates.

Staining would appear to occur in two distinct forms, brought about by different mechanisms: pattern and migration.

Common sealant failures on facade include problems associated with:

-adhesion
-cohesion
-hardening
-weathering
-crazing
-softening
-decomposition
-chalking
-cracking
-loss of elasticity

See also: Material Manual > Facade > Cladding > Jointing Materials > Sealants