Sealant fails for a variety of reasons: improper joint sizing, incorrect sealant chosen for the project, substrate failure and application error, which can all be summed up to simply be “a lack of attention to detail.”
The prevention of sealant failure can be accomplished in numerous ways. To start, ensure the joints are designed to reflect correct expansion and contraction of the building material. Pay attention to joint sizing, location and spacing, which is critical to the success of the sealant. Define the purpose of the sealant and choose the one that best addresses the need and is the most compatible for the building material. Finally, proper preparation and application is imperative; the failure to execute this critical step will negate even the best specifications.
We advise customers to have their sealant supplier conduct accelerated aging tests to determine if there might be bleeding of the sealant carrier into the stone. The sealant supplier should also recommend a primer that will NOT bleed into the stone. A customer should require a sealant warranty for bond to stone and also a warranty against staining from the sealant supplier.
The importance of sealant is often undervalued. It is only a small portion of a very large exterior but it plays a critical role. Lack of attention to sealant detail can result in building structural failures.