Silicone or Urethane? Simplifying the Selection Process

The sealant selection process can be daunting.   We’ve tried to simplify the decision making process with the tips below but we recommend that you always check in with Pecora’s Technical Service Department when weighing products against applications.

When choosing a sealant chemistry there are a few rules that will uncomplicate the decision making process:

• Become familiar with performance criteria
• Consider life cycle costs including expected longevity of the sealant and manufacturer warranties
• When in doubt, contact Pecora Techincal Services

Silicone vs. Urethane Features:
Different chemistries have different properties making them more or less appropriate for a particular application.  The properties of Silicones and Urethanes are listed below:

Silicones:
– Key Ingredients:  Silane/siloxane
– 1 or 2 part systems
– high movement
– UV resistant
– longevity
– high temperature
– 10-20 year warranty for many building projects

Urethanes:
– Key Ingredients:  diisocyanate, polyol, and catayst
– 1 or 2 part
– moderate movement
– paintable
– non- staining
– 5 year warranty for many building projects

Silicone vs. Urethane Specifications:
Building specifications often dictate that a sealant meet particular testing standards.  The testing standards required may vary by sealant chemistry- silicone or urethane.  The more common tests applied to silicones and urethane sealants are:

Silicones:
– ASTM C920
– Federal TT-S-001543
-ASTM D-5893

Urethanes:
-ASTM C920
-Federal TT-S-00230 and Federal TT-S-00227
– SS-S-200E

Typical Project Applications by Chemistry: 

Silicones:
– Window Glazing
– Structural Glazing
– Masonry
– Traffic Areas

Urethanes:
– Masonry
– Natural Stone
– Traffic Areas
– Security