Expansion
Joint SealingFLEXIBLE · MOVEMENT-RATED · WATERTIGHT
A flexible movement-joint system that seals the deliberate gaps a structure needs to expand and contract. The joint is cleaned and profiled, a backer rod sets the correct depth, and a high-movement sealant is applied — keeping the joint watertight and debris-free while it flexes through thermal and structural movement.
What is Expansion Joint Sealing?
Expansion joint sealing is the treatment of the deliberate movement gaps built into a structure so it can expand, contract and shift safely. Unlike a crack, an expansion joint is meant to move — so it cannot be filled rigidly. The joint is cleaned and profiled, a backer rod is inserted to set the correct sealant depth, and a flexible, high-movement sealant is installed that stretches and compresses with the joint while staying watertight and debris-free. It is delivered as a POLYZEN Applied System, surveyed and installed by trained applicators.
How the Joint Is Sealed
A movement joint is sealed to flex, not to lock — cleaned, depth-controlled with a backer rod, then sealed with a flexible high-movement material. Tap any stage to see its role.
Tooling & Cure
The sealant is tooled to the correct concave profile for even stress distribution and full contact with the joint walls, then left to cure into a flexible, watertight seal. System values: Per TDS.
Delivered as a POLYZEN Applied System
This joint is sealed as a POLYZEN Applied System — surveyed, specified and installed turnkey by trained applicators using high-movement sealants, backer rods and primers. The sealant class, joint sizing and bond profile are selected per joint type, width and expected movement.
A Seal That Moves With the Structure
An expansion joint fails when it is filled with the wrong, rigid material — it cracks loose the first time the structure moves and lets water straight in. POLYZEN treats the joint as a moving component: the right movement-class sealant, the correct width-to-depth ratio set by a backer rod, and a two-sided bond that lets the seal stretch and recover. Sealant class and sizing are matched to each joint. Performance is confirmed on the product TDS.
Sealant movement class, backer-rod size and bond profile are specified per joint type, width and expected movement. Heavy-traffic or trafficked deck joints may need a trafficable joint system. POLYZEN confirms finished values on the product TDS and does not publish fabricated figures.
The Application Process
Inspect & Size
Assess joint type, width and movement range, then specify the sealant class, backer rod and profile.
Clean & Prime
Remove old sealant and debris, clean and profile the joint walls, then prime where required.
Rod & Seal
Set the backer rod to depth, then gun-apply and tool the flexible high-movement sealant.
Cure & Handover
Allow cure, final inspection of the bond profile and written warranty.
System Specifications
| Property | Detail |
|---|---|
| System Type | Expansion / Movement Joint Sealing |
| Delivery | POLYZEN Applied System (turnkey) |
| Method | Clean · backer rod · flexible sealant · tool |
| Sealant | High-movement PU / hybrid sealant |
| Joint Prep | Cleaned · profiled · primed walls |
| Application | Floors · decks · facades · podiums · tanks |
| Function | Watertight movement-rated seal |
| Coverage / Values | Per Product TDS |
Ideal Applications
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Applied & Warranted
Every POLYZEN joint-sealing project is carried out by trained applicators and handed over after a final inspection and a written system warranty. Warranty terms are confirmed per joint type, width and expected movement.
Frequently Asked Questions
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Seal Every Moving Joint.
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