Identifying Causes of Sealant Failure

1.  Aging

• Sealant has reached its maximum service life and has become dry, brittle, cracked and/or crazed and shows sign of significant aging.

2. Incorrect Sealant for Application  

• Sealant installed was not appropriate for application due to inadequate performance characteristics.  The correct sealant should be identified based on the nature of the sealant failures observed.

3.  Inadequate Surface Preparation

• Sealant is exhibiting adhesive failure due to dirt, dust, debris, and/or other contaminants present on joint face at time of sealant application.
• Omission of manufacturer’s required sealant primer. 
  

4.  Excessive Joint Movement

• Actual thermal joint movement has exceeded the designed movement capabilities of the installed joint sealant causing cohesive sealant failures. 

5.  Early Joint Movement During Sealant Cure Cycle

• Early joint movement caused by extreme temperature swings has occurred during the initial sealant cure cycle and has caused surface wrinkling and/or cracking leading to cohesive sealant failures.

6.  Improper Sealant Application

• Improper sealant dimensions (width to depth ratio) leading to excessive or insufficient sealant depth.

• Sealant was not properly mixed leading to insufficient cure and poor sealant performance (applicable to multi-component sealants only).

• Three-sided adhesion due to inappropriate or non-existent sealant backing.

• Inadequate sealant tooling causing lack of contact at sealant / substrate interface resulting in adhesive failures or insufficient cure.

7.  Incompatibility 

• Sealant and substrate incompatible causing an adverse reaction at the sealant/substrate interface.

Note:  All of the above sealant failures will most likely lead to air and/or water infiltration into occupied space and should be repaired immediately.  

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