Reversion happens when the crosslinked rubber depolymerizes. Some polyurethane and polysulfide formulations are prone to it under heat, humidity and UV, and chemical exposure or incompatible materials can trigger it in any type. A reverted sealant loses elasticity, picks up dirt and no longer seals. It must be fully removed before resealing, because new sealant will not bond to it.
Old urethane on the south face has reverted, it's like chewing gum, scrape every bit out before we reseal.
Also heard as
- reverting
Related terms
Polysulfide
An elastomeric sealant, usually two-part, chosen for joints exposed to fuel, chemicals or constant immersion.
Polyurethane sealant
A tough, paintable elastomeric sealant used widely on concrete, masonry and traffic joints.
R&R
Remove and replace: cutting out old sealant completely and installing new sealant in the cleaned joint.
Compatibility test
A lab check that a sealant and the materials it touches do not react, discolor or lose adhesion together.