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Views: 0 Author: Site Editor Publish Time: 2026-05-21 Origin: Site
Concrete structures need joints. Some are planned, some are unavoidable. The decision to use a waterstop alone, combine it with polyurethane or polysulfide sealant, or use sealant independently depends on what the joint does and what it is exposed to.
Sealant plays a dual role. In open, moving joints, it pairs with waterstops as part of a multi-layer defense. In applications where no waterstop is involved, it works alone — sealing expansion joints in concrete structures, filling precast panel gaps, and restoring watertightness to cracked surfaces.
Waterstop is the primary defense. A rubber, PVC or steel-edged waterstop blocks water along the bonding surface. The real priority is surface preparation: cleaning laitance, exposing aggregate, and moistening the old concrete before the next pour.
A movement joint is a deliberate break, designed to accommodate thermal expansion, contraction and seismic displacement. The joint is open, with reinforcement fully cut. Both sides move independently. The gap is visible and must remain functional throughout the structure's service life.
A settlement joint separates structural sections with significantly different loads or foundation conditions. Each side settles independently. The displacement is typically permanent and gradual, unlike the cyclic movement of an expansion joint.
A post-cast strip is a temporary gap left during main construction. It allows the structure to undergo initial shrinkage and settlement before the strip is filled with concrete. Once shrinkage stabilizes, the strip is poured, and the structure becomes continuous. After closure, the joint no longer exists in the traditional sense.
The decision to use waterstop alone, add sealant, or use sealant independently depends on three factors:
Is the joint permanently open to water ingress?
Does the joint undergo movement?
Is the application a structural joint, or a surface-level sealing need?
When a joint is permanently open and actively moves, two layers are required — polyurethane or polysulfide sealant on the surface, waterstop inside. When a joint is fully encased in concrete and does not move, a properly installed waterstop is sufficient. When the task does not involve a structural joint at all, sealant works as the primary and only barrier.
Waterstop is the primary defense. A rubber, PVC or steel-edged waterstop blocks water along the bonding surface. The real priority is surface preparation: cleaning laitance, exposing aggregate, and moistening the old concrete before the next pour.
Both waterstop and sealant are mandatory. The open gap allows direct water entry. Sealant fills the gap and blocks surface water as the first barrier. The waterstop inside acts as the second barrier. Polyurethane sealant suits cyclic movement. Polysulfide sealant suits submerged conditions.
Both barriers are needed. Settlement causes permanent displacement. Sealant accommodates this slow deformation at the surface. The waterstop inside handles water that passes the sealant. Polysulfide sealant is often preferred for its long-term flexibility.
Waterstop is the main defense. Once the strip is poured, the structure is continuous. Proper interface preparation between old and new concrete ensures a tight bond.
Polyurethane and polysulfide sealants also work as the primary waterproofing barrier in common concrete sealing applications where no waterstop is present.
Building Construction
Concrete expansion joints, precast connections.
Bridge Construction
Bridge expansion joints, girder end gaps.
Municipal Facilities
Wastewater tanks, reservoir joints.
Transportation
Airport runways, highway pavement joints.
Industrial Buildings
Chemical plant floor joints, equipment foundation gaps.
Joint Type | Waterstop | Sealant | Critical Factor |
Construction Joint | Required | ----- | Surface prep + concrete compaction |
Movement Joint | Required | Required | Movement capacity + dual barrier |
Settlement Joint | Required | Required | Long-term flexibility + permanent displacement |
Post-Cast Strip | Required | ----- | Old-to-new concrete interface bond |
Sector | Application | Function |
Building Construction | Concrete expansion joints, precast connections | Movement accommodation, panel gap sealing |
Bridge Construction | Bridge expansion joints, girder end gaps | Traffic load resistance, water and debris exclusion |
Municipal Facilities | Wastewater tanks, reservoir joints | Submerged service, chemical resistance |
Transportation | Airport runways, highway pavement joints | Dynamic load and weather resistance |
Industrial Buildings | Chemical plant floor joints, equipment foundation gaps | Chemical spill and vibration resistance |
All three materials must always be used together.
No. A construction joint functions reliably with a waterstop alone. A closed post-cast strip does not need surface sealant. Sealant also works independently in applications where no waterstop is present.
Sealant is only a secondary material to waterstop.
No. In movement and settlement joints, sealant is the first barrier. In standalone applications, sealant is the only waterproofing material.
A waterstop can replace sealant.
No. Movement and settlement joints are open. Without sealant, water enters freely and the waterstop faces the full hydraulic load alone. In standalone applications, there is no space for a waterstop--only sealant works there.
We manufacture rubber waterstops, PVC waterstops and steel-edged waterstops for structural joint waterproofing. We also supply polyurethane and polysulfide sealants as standalone waterproofing products. For structural joints, we help configure the right waterstop and sealant combination. For building, bridge, municipal, transportation and industrial projects where sealant works alone, our sealants deliver primary waterproofing performance.
