Sealant Movement Capability
The percentage of a joint's width that a sealant can accommodate in extension and compression without failing, stated by the manufacturer.
On an actual building
It must exceed the joint's actual design movement. Under-specifying here guarantees a tear, and it is why a resealed joint sometimes fails again within a single season.
What we most often have to correct
That all sealants are broadly similar. Movement classes differ substantially and are the deciding property for a moving joint.
Terms that come up alongside this one
- Backer Rod
A closed-cell foam rod pressed into a joint before sealant, setting the correct sealant depth and preventing it bonding to the joint base..
- Expansion Joint
A deliberate gap through a structure that allows adjacent parts to move independently under thermal and structural movement..
- Thermal Movement
Expansion and contraction of building materials as temperature changes.
Sealant Movement Capability — questions we get asked
What does sealant movement capability mean in waterproofing?
The percentage of a joint's width that a sealant can accommodate in extension and compression without failing, stated by the manufacturer.
Why does sealant movement capability matter on a real project?
It must exceed the joint's actual design movement. Under-specifying here guarantees a tear, and it is why a resealed joint sometimes fails again within a single season.
What do people commonly get wrong about sealant movement capability?
That all sealants are broadly similar. Movement classes differ substantially and are the deciding property for a moving joint.
Have a building showing this?
If a term on this page describes something you are looking at, a site inspection will tell you how far it has gone and what it needs. It costs nothing.
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