Choosing the right expansion joint sealant is critical to the long-term performance of movement joints in concrete, façades, floors, precast elements, parking structures, pavements, and other construction applications.

An expansion joint sealant does more than fill a visible gap. It creates a flexible sealing zone that must accommodate the designed opening and closing of the joint while maintaining adhesion to suitable joint faces and helping limit the entry of water, dust, dirt, and other contaminants.

The right solution depends on the actual conditions of the joint, including:

• Expected movement

• Joint width and depth

• Substrate type and condition

• Horizontal or vertical orientation

• Water and moisture exposure

• UV and weather exposure

• Chemical or seawater exposure

• Traffic and abrasion

• Backing and primer requirements

• Application and curing conditions

This is why there is no single expansion joint sealant that is automatically “best” for every project.

A polyurethane sealant suitable for a concrete movement joint or parking floor may not be the right solution for a joint exposed to demanding chemicals, seawater, asphalt, or a bituminous waterproofing system.

iChem provides joint sealing solutions based on polyurethane, polysulphide, and bituminous technologies, together with complementary joint filling and backing materials. Each technology serves different technical requirements and should be evaluated against the project specification and the current Technical Data Sheet for the selected product.

This guide explains what expansion joint sealants are, how they work, how to select the right technology, how iChem joint sealing solutions compare, and which factors should be checked before specification and application.

An expansion joint sealant is a flexible sealing material installed within a movement joint to accommodate designed movement while helping limit the entry of water, dust, dirt, and other contaminants.

Expansion and movement joints are intentionally incorporated into structures because construction materials do not remain completely static.

Movement may result from:

• Temperature changes

• Thermal expansion and contraction

• Drying shrinkage

• Structural movement

• Building tolerances

• Environmental conditions

• Service-related loads

As adjacent construction elements move, the joint width may increase or decrease.

The sealant installed within that joint must therefore be capable of deforming within its specified movement range while maintaining appropriate adhesion to properly prepared joint faces.

For this reason, selecting a sealant simply because it is described as suitable for “concrete” or “expansion joints” is not enough.

The complete joint condition should be evaluated.

An expansion joint sealant creates a flexible sealing zone between adjacent construction surfaces.

When the joint opens, the sealant extends.

When the joint closes, the sealant compresses.

A correctly specified sealant is designed to accommodate this movement within its documented limits while maintaining adhesion to compatible and properly prepared substrates.

A properly designed and installed joint sealing system can help:

• Accommodate specified expansion and contraction

• Maintain a flexible seal between adjacent surfaces

• Limit water ingress

• Reduce the entry of dust and contaminants

• Protect the joint from relevant environmental exposure

• Support long-term joint serviceability

However, the sealant should not be considered in isolation.

Depending on the joint design, a complete system may also include:

• Backer rod

• Joint filler

• Primer

• Bond-breaking material

• Engineered expansion joint components

The interaction between these components can be just as important as the chemistry of the sealant itself.

Movement joints are designed to move.

If the material installed in the joint cannot accommodate that movement—or if the joint is incorrectly designed or installed—stresses can develop within the sealant or at the sealant-to-substrate interface.

Potential problems may include:

• Loss of adhesion

• Internal tearing

• Cracking

• Water ingress

• Premature deterioration

• Repeated joint failure

Sealant performance therefore depends on the relationship between several factors:

Movement → Joint Geometry → Substrate → Backing → Sealant Technology → Exposure → Application → Service Conditions

This becomes particularly important in joints exposed to:

• Repeated temperature cycles

• Rain and weather

• UV radiation

• Vehicle or pedestrian traffic

• Abrasion

• Moisture or water

• Seawater

• Oils or fuels

• Chemical exposure

The objective is not to select the product with the longest list of properties.

The objective is to select a joint sealing system whose documented performance matches the conditions it will actually experience.

An expansion joint sealant and a joint filler can form part of the same joint system, but they perform different functions.

An expansion joint sealant generally forms the flexible exposed sealing zone.

It is selected according to factors such as:

• Movement capability

• Adhesion

• Joint geometry

• Substrate compatibility

• Environmental exposure

• Service conditions

A joint filler or backing material may instead occupy part of the joint, provide separation, support the required sealant profile, or help control the depth of the sealant.

Expansion Joint Sealant vs. Joint Filler

For example, a project may use a compressible filler or backing material to establish the required joint configuration, with a flexible sealant forming the exposed sealing zone above it.

The exact build-up should follow the project specification and the technical requirements of the selected system.

The right expansion joint sealant should be selected by defining the joint requirements first and then comparing those requirements with the documented performance of the proposed product.

Instead of beginning with:

“Which sealant should I use?”

begin with:

“What does this joint require the sealant to do?”

A practical selection process should evaluate the following factors.

Start by identifying the function of the joint.

Depending on the project, it may be an:

• Expansion joint

• Movement joint

• Construction joint

• Contraction joint

• Connection joint

• Precast concrete joint

• Floor joint

• Façade joint

• Pavement joint

These terms should not automatically be treated as interchangeable.

Different joint types can experience different movement patterns, substrates, environmental conditions, and mechanical demands.

Understanding the joint function establishes the basis for the rest of the selection process.

Movement capability is one of the most important technical parameters in expansion joint sealant selection.

As the joint opens and closes, the installed sealant deforms.

The expected movement should therefore remain within the documented movement capability of the selected product.

Different sealant technologies—and even different products within the same chemical family—can have different movement capabilities.

For example:

• ChemSeal 1® has a stated movement capability of ±25%.

• ChemSeal PS® has a stated movement factor of ±50%.

Technical Data Sheets:

• ChemSeal 1® Technical Data Sheet

• ChemSeal PS® Technical Data Sheet

These movement values are important technical selection parameters, but they should not be interpreted as a simple product ranking.

A higher movement value does not automatically mean that one sealant is better for every application.

Substrate compatibility, joint geometry, exposure, application conditions, and the complete joint design must also be considered.

Joint geometry directly influences how a flexible sealant responds to movement.

A deeper sealant bead is not automatically stronger or more durable.

Incorrect width-to-depth geometry can change the stress distribution within the sealant and prevent it from behaving as intended.

The required dimensions should therefore be taken from the technical documentation for the exact product being specified.

For example, the ChemSeal 1® Technical Data Sheet provides product-specific joint geometry guidance, including a generally recommended 2:1 width-to-depth relationship for applicable joint dimensions.

The documentation also states:

• Minimum joint depth: 8 mm

• Maximum joint width: 50 mm

• 10 mm joint: 1:1 profile

Technical reference: ChemSeal 1® Technical Data Sheet

These values are specific to ChemSeal 1® and should not automatically be applied to ChemSeal PU®, ChemSeal PS®, ChemJoint®, or another joint sealing product.

Joint geometry should always be verified against the current Technical Data Sheet for the selected product.

The materials forming the joint faces are a critical part of sealant selection.

Possible substrates include:

• Concrete

• Precast concrete

• Masonry

• Asphalt

• Metal

• Compatible façade materials

• Compatible waterproofing systems

Both substrate type and substrate condition matter.

For example, sound and properly prepared concrete does not provide the same bonding conditions as concrete contaminated with:

• Dust

• Oil

• Grease

• Laitance

• Loose particles

• Curing compounds

• Weak surface material

• Residues from previous sealants

The selected sealant must be compatible with the intended substrate, and the required surface preparation and primer recommendations should be followed.

A horizontal floor joint and a vertical façade joint can place very different demands on a sealant.

For vertical applications, the material must maintain the required profile during application.

Horizontal joints may face additional conditions such as:

• Vehicle traffic

• Pedestrian traffic

• Abrasion

• Dirt and debris

• Standing or intermittent water

• Cleaning equipment

• Mechanical exposure

Orientation should therefore be considered alongside movement, geometry, substrate, and service conditions—not as an isolated selection factor.

Not all wet or chemically exposed environments create the same requirements.

A joint exposed to occasional rain is different from one exposed to:

• Continuous moisture

• Seawater

• Oils

• Fuels

• Cleaning chemicals

• Industrial chemicals

• Water channels

Where chemical exposure is expected, identify:

• The chemical or liquid

• Concentration

• Exposure duration

• Temperature

• Whether exposure is occasional or continuous

• Additional cleaning chemicals

• Expected joint movement

For demanding exposure conditions, the documented resistance of the proposed sealant should be compared with the specific service environment.

For example, ChemSeal PS® provides documented resistance characteristics relevant to specified chemical and seawater exposure.

Technical reference: ChemSeal PS® Technical Data Sheet

Chemical or seawater resistance should still be verified against the actual project conditions before specification.

Exterior movement joints can experience repeated environmental cycles throughout their service life.

These may include:

• UV radiation

• Rain

• Temperature fluctuations

• Wind-driven moisture

• Repeated expansion and contraction

Where these conditions are relevant, evaluate the product's documented:

• UV resistance

• Weather resistance

• Adhesion

• Movement capability

• Exterior application suitability

For example, ChemSeal 1® provides documented weather and UV resistance and is intended for suitable exterior construction applications.

Technical reference: ChemSeal 1® Technical Data Sheet

Parking structures, floors, pedestrian zones, and pavements can expose joints to additional mechanical demands.

Selection should consider:

• Vehicle traffic

• Pedestrian traffic

• Abrasion

• Impact near joint edges

• Cleaning equipment

• Dirt and debris

• Loading conditions

• Movement during service

ChemSeal 1®, for example, includes parking-floor applications within its technical documentation and provides documented wear and abrasion resistance.

Technical reference: ChemSeal 1® Technical Data Sheet

However, traffic alone should never determine the product.

Joint movement, geometry, substrate condition, exposure, location, and the complete project detail must also be evaluated.

A sealant may be technically suitable for the completed joint but still require specific conditions during installation.

Before specification or application, verify:

• Surface condition

• Moisture requirements

• Application temperature

• Primer requirements

• Backing material

• Mixing requirements

• Sealant depth

• Tooling requirements

• Cure conditions

• Protection during curing

Application requirements can differ significantly between technologies.

For example:

ChemSeal 1® and ChemSeal PU® are one-component polyurethane systems.

ChemSeal PS® is a two-component polysulphide system.

ChemJoint® is a single-component, cold-applied bituminous joint sealing compound that does not require heating or two-component mixing before application.

Technical Data Sheets

• ChemSeal 1® TDS

• ChemSeal PU® TDS

• ChemSeal PS® TDS

• ChemJoint® TDS

These differences affect installation planning and should be considered during product selection—not after the material arrives on site.

The final step before specification is technical verification.

Compare the project requirements with the current Technical Data Sheet for the exact product.

Check relevant information such as:

• Movement capability

• Intended applications

• Compatible substrates

• Joint dimensions

• Application limits

• Surface preparation

• Primer requirements

• Resistance characteristics

• Curing conditions

• Limitations

• Storage and handling requirements

Two products can belong to the same chemical family and still have different performance characteristics.

Similar chemistry does not mean identical technical performance.

The most reliable selection principle is therefore:

Choose the sealant from the joint requirements—not the joint requirements from the sealant.

Before moving a sealant forward for final specification, confirm:

• Joint type: What is the joint designed to do?

• Movement: What opening and closing movement is expected?

• Width: What is the designed joint width?

• Depth: What sealant depth is required?

• Substrate: Which materials form the joint faces?

• Orientation: Is the joint horizontal, vertical, or overhead?

• Water exposure: Will the joint experience moisture or water?

• Chemical exposure: Are chemicals, oils, fuels, or cleaning agents expected?

• Weather: Will the joint experience UV, rain, or temperature cycles?

• Traffic: Will vehicles, pedestrians, or equipment affect the joint?

• Backing: Is a backer rod or joint filler required?

• Primer: Does the selected system require priming?

• Application: Can the required installation conditions be achieved?

• Technical data: Has the current product TDS been checked?

• Project specification: Does the proposed system satisfy the design requirements?

Once these conditions are defined, the appropriate sealant technology can be evaluated much more accurately.

Expansion joint sealants are available in different chemistries, and each technology has its own movement characteristics, application requirements, substrate compatibility, and resistance to environmental or service conditions.

For construction and movement joints, three important sealant technologies are:

• Polyurethane joint sealants

• Polysulphide joint sealants

• Bituminous joint sealants

The correct technology should be selected according to the actual joint requirements—not simply by choosing the material with the highest movement capability or the longest list of properties.

Polyurethane joint sealants are flexible sealing materials widely used for movement, connection, concrete, precast, floor, façade, and other construction joints where elasticity and adhesion are required.

Depending on the formulation, polyurethane sealants can provide a useful combination of:

• Flexibility

• Adhesion to suitable construction substrates

• Weather resistance

• UV resistance

• Abrasion resistance

• Convenient one-component application

Polyurethane technology can be particularly relevant for suitable concrete movement joints, parking floors, precast elements, connection joints, and exterior construction applications.

However, not every polyurethane sealant provides the same movement capability, joint geometry, resistance characteristics, or application requirements.

Within the iChem range, polyurethane joint sealing solutions include:

• ChemSeal 1®

• ChemSeal PU®

Technical Data Sheets

• ChemSeal 1® Technical Data Sheet

• ChemSeal PU® Technical Data Sheet

The exact product should be evaluated against the project requirements rather than selected based on polyurethane chemistry alone.

Polysulphide joint sealants are flexible sealing systems that can be considered where movement performance and resistance to demanding environmental or chemical exposure are important project requirements.

Depending on the product specification, polysulphide systems may be relevant for:

• Expansion and movement joints

• Concrete construction joints

• Vertical joints

• Horizontal joints

• Thermal movement

• Weather exposure

• Seawater exposure

• Relevant chemical exposure

Within the iChem range, ChemSeal PS® is a two-component polysulphide joint sealant designed for suitable vertical and horizontal construction joints.

Technical Data Sheet

ChemSeal PS® Technical Data Sheet

Polysulphide technology can be particularly relevant where the service conditions extend beyond ordinary weather exposure, but the exact chemical, movement, substrate, and application requirements should still be verified.

Bituminous joint sealing compounds serve a different group of applications where compatibility with concrete, asphalt, pavement, flooring, water channels, or bituminous construction systems is required.

They should not be treated as direct alternatives to polyurethane or polysulphide sealants based only on flexibility.

A bituminous joint sealing system may be appropriate for selected:

• Concrete surfaces

• Asphalt surfaces

• Pavement joints

• Flooring joints

• Water channels

• Compatible waterproofing details

• Other suitable bituminous construction applications

Within the iChem range, ChemJoint® is a single-component, cold-applied bituminous jointing and sealing compound.

Technical Data Sheet

ChemJoint® Technical Data Sheet

The product should be evaluated according to substrate and system compatibility, joint function, application conditions, and the project specification.

The difference between polyurethane, polysulphide, and bituminous joint sealants extends beyond their chemical composition.

The technologies can also differ in:

• Movement characteristics

• Application method

• Mixing requirements

• Environmental resistance

• Substrate compatibility

• Intended applications

• Service conditions

The following table provides an initial comparison.

Important: This comparison is intended for preliminary technical screening. Final product selection should follow the project specification and the current Technical Data Sheet for the exact product being considered.

iChem provides different joint sealing technologies for different construction requirements.

Rather than asking which iChem sealant is “best,” the more useful approach is to match each product with the conditions it is designed to address.

A practical sequence is:

Joint Function → Movement → Geometry → Substrate → Orientation → Exposure → Traffic → Application Conditions → Product

The following iChem solutions should therefore be considered as different technical options rather than interchangeable products.

ChemSeal 1® is a one-component polyurethane joint sealant designed to provide a flexible and durable seal for suitable movement and connection joints.

It combines permanent elasticity with adhesion to suitable construction substrates and documented resistance to weathering and UV exposure.

According to its Technical Data Sheet, ChemSeal 1® has a stated movement capability of ±25%.

Where Can ChemSeal 1® Be Used?

Its documented applications include suitable:

• Expansion and movement joints

• Connection joints

• Parking floors

• Precast concrete panels

• Concrete construction applications

• Façade-related joints

• Glazing-related applications

• Areas where UV and weather resistance are relevant

Key Characteristics of ChemSeal 1®

• One-component polyurethane technology

• Permanent elasticity

• ±25% movement capability

• Weather resistance

• UV resistance

• Wear and abrasion resistance

• Suitable for appropriate vertical and horizontal applications

• No two-component mixing process required

ChemSeal 1® Joint Geometry

Joint geometry is an important part of ChemSeal 1® specification.

Its Technical Data Sheet provides product-specific guidance including a generally recommended 2:1 width-to-depth relationship for applicable joint dimensions.

The documentation also states:

• Minimum joint depth: 8 mm

• Maximum joint width: 50 mm

• 10 mm joint: 1:1 profile

These dimensions are product-specific and should not automatically be transferred to another sealant.

ChemSeal 1® Technical Resources

Product Page:
View ChemSeal 1® Product Page

Technical Data Sheet:
Download ChemSeal 1® Technical Data Sheet

ChemSeal PU® is a one-component, moisture-curing polyurethane sealing compound developed for flexible sealing applications, including suitable expansion and contraction joints.

It provides another polyurethane option where elasticity, adhesion, and flexible sealing performance are required.

Where Can ChemSeal PU® Be Used?

ChemSeal PU® can be considered for suitable:

• Expansion joints

• Contraction joints

• Vertical joints

• Horizontal joints

• Concrete construction joints

• Small joints and fillets

• Flexible construction sealing applications

Key Characteristics of ChemSeal PU®

• One-component polyurethane technology

• Moisture-curing

• Flexible sealing performance

• Adhesion to suitable substrates

• Weather-resistant characteristics

• Suitable for appropriate vertical and horizontal applications

• Designed for expansion and contraction joints

ChemSeal PU® vs. ChemSeal 1®

Both products use polyurethane technology, but the same chemistry does not make them interchangeable.

Selection should compare their individual:

• Intended applications

• Movement requirements

• Joint geometry

• Substrate compatibility

• Application conditions

• Exposure requirements

• Technical limitations

The appropriate product is the one whose documented characteristics match the project requirements—not simply the one that belongs to the same chemical family.

ChemSeal PU® Technical Resources

Product Page:
View ChemSeal PU® Product Page

Technical Data Sheet:
Download ChemSeal PU® Technical Data Sheet

ChemSeal PS® is a two-component, non-sag polysulphide joint sealant designed for flexible sealing of suitable vertical and horizontal construction joints.

It is particularly relevant where movement capability and demanding environmental exposure form part of the project requirements.

According to its Technical Data Sheet, ChemSeal PS® has a stated movement factor of ±50%.

Where Can ChemSeal PS® Be Used?

Its documented applications include suitable:

• Concrete construction joints

• Expansion and movement joints

• Vertical joints

• Horizontal joints

• Joints subject to thermal movement

• Weather-exposed joints

• Applications requiring documented seawater resistance

• Applications involving relevant chemical exposure

Key Characteristics of ChemSeal PS®

• Two-component polysulphide technology

• Non-sag formulation

• ±50% movement factor

• Suitable for appropriate vertical and horizontal joints

• Seawater resistance

• Resistance to specified chemical exposure

• Weather resistance

• Flexible joint sealing performance

Does ±50% Make ChemSeal PS® the Best Expansion Joint Sealant?

No.

The stated ±50% movement factor is an important technical parameter, but a higher movement capability does not automatically make ChemSeal PS® the correct product for every expansion joint.

Selection must still consider:

• Actual joint movement

• Substrate

• Joint dimensions

• Joint orientation

• Chemical or environmental exposure

• Application conditions

• Complete joint design

For example, a parking-floor joint requiring a polyurethane system may have different priorities from a chemically exposed construction joint, even if both joints experience movement.

ChemSeal PS® Joint Geometry

The ChemSeal PS® Technical Data Sheet provides product-specific recommendations for joint geometry, including a 2:1 width-to-depth profile for applicable joint dimensions.

The required profile should be verified against the current product documentation before specification or application.

ChemSeal PS® Technical Resources

Product Page:
View ChemSeal PS® Product Page

Technical Data Sheet:
Download ChemSeal PS® Technical Data Sheet

ChemJoint® is a single-component, cold-applied bituminous jointing and sealing compound developed for compatible concrete, asphalt, pavement, flooring, and related construction applications.

Unlike ChemSeal 1®, ChemSeal PU®, and ChemSeal PS®, ChemJoint® uses bituminous technology and therefore serves a different group of joint sealing requirements.

The product is supplied ready for cold application and does not require heating or two-component mixing before use.

Where Can ChemJoint® Be Used?

Its documented applications include suitable:

• Concrete surfaces

• Asphalt surfaces

• Flooring joints

• Pavement joints

• Canals and water channels

• Areas around suitable pipe penetrations

• Compatible bituminous waterproofing applications

Key Characteristics of ChemJoint®

• Single-component system

• Bituminous joint sealing technology

• Cold applied

• No heating required

• No two-component mixing required

• Suitable for compatible concrete and asphalt applications

• Applicable to selected pavement and flooring joints

• Compatible with relevant bituminous construction systems

When Should a Bituminous Joint Sealant Be Considered?

ChemJoint® should not be selected by comparing its flexibility with polyurethane or polysulphide products alone.

Instead, evaluate:

• Substrate compatibility

• Joint function

• Pavement or flooring conditions

• Surrounding waterproofing system

• Environmental exposure

• Application requirements

Where these conditions indicate that a cold-applied bituminous joint sealing compound is technically appropriate, ChemJoint® can be evaluated against the project specification.

ChemJoint® Technical Resources

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
Download ChemJoint® Technical Data Sheet

There is no single iChem joint sealant that should automatically be specified for every expansion joint.

The most useful comparison is based on technology, documented performance, intended application, and project conditions.

The appropriate product depends on the conditions of the project rather than a universal product ranking.

For Flexible Concrete Movement Joints

Evaluate ChemSeal 1® or ChemSeal PU® where their documented polyurethane properties match the required movement, substrate, geometry, orientation, and exposure.

For Higher Documented Movement Requirements

Evaluate ChemSeal PS® where its stated ±50% movement factor and other technical characteristics match the complete joint requirements.

A higher movement value should not be used as the only selection criterion.

For Chemical or Seawater Exposure

Evaluate ChemSeal PS® where its documented resistance characteristics correspond to the actual service environment.

The specific chemical, concentration, temperature, duration, and frequency of exposure should still be verified.

For Parking-Floor Applications

Evaluate ChemSeal 1® where its documented movement, wear, abrasion, substrate, and application characteristics meet the project requirements.

For Precast Concrete and Suitable Exterior Joints

Evaluate ChemSeal 1® where movement, adhesion, UV resistance, weather resistance, and joint geometry meet the specification.

For Expansion and Contraction Joints Requiring a Polyurethane System

Evaluate ChemSeal PU® or ChemSeal 1® according to the exact joint dimensions, movement, substrate, exposure, and application requirements.

For Concrete, Asphalt, Pavement, and Compatible Bituminous Applications

Evaluate ChemJoint® where a cold-applied bituminous joint sealing compound is technically appropriate for the substrate, joint function, and surrounding construction system.

Important: This table is intended for preliminary product screening. Final selection should follow the project specification and the current Technical Data Sheet for the proposed product.

For technical verification, use the current documentation for the exact product under consideration:

• ChemSeal 1® — Product Page | Technical Data Sheet

• ChemSeal PU® — Product Page | Technical Data Sheet

• ChemSeal PS® — Product Page | Technical Data Sheet

• ChemJoint® — Joint Sealant Product Range | Technical Data Sheet

Always verify the current Technical Data Sheet and project specification before final product selection.

Expansion joint sealants are used across a wide range of construction applications, but the application name alone does not determine the correct product.

Two joints described as concrete expansion joints, for example, may have very different technical requirements if one is located in an exterior façade and the other in a traffic-exposed parking floor.

A practical application-based selection process should consider:

Application → Movement → Geometry → Substrate → Exposure → Mechanical Demands → Sealant Performance

The following sections explain how these factors apply to common construction joint conditions.

Concrete expansion and movement joints require a flexible sealing system capable of accommodating the expected movement while maintaining appropriate adhesion to properly prepared joint faces.

When selecting an expansion joint sealant for concrete, consider:

• Expected movement

• Joint width and depth

• Concrete condition

• Horizontal or vertical orientation

• Water exposure

• UV and weather exposure

• Traffic and abrasion

• Chemical exposure

• Required backing material

• Primer requirements

• Application conditions

Polyurethane and polysulphide technologies can both be considered for suitable concrete movement joints when their documented properties match the project requirements.

Relevant iChem solutions include:

• ChemSeal 1® — one-component polyurethane joint sealant

• ChemSeal PU® — one-component moisture-curing polyurethane sealant

• ChemSeal PS® — two-component polysulphide joint sealant

Technical Data Sheets

• ChemSeal 1® TDS

• ChemSeal PU® TDS

• ChemSeal PS® TDS

The final product should be selected according to the specific concrete joint conditions rather than the substrate name alone.

Concrete floor joints may experience more than movement.

Depending on the location and use of the floor, the joint may also be exposed to:

• Pedestrian traffic

• Vehicle traffic

• Abrasion

• Cleaning operations

• Dirt and debris

• Water

• Mechanical impact

• Chemicals or oils

A sealant selected for a concrete floor should therefore be evaluated for both movement performance and service exposure.

ChemSeal 1® includes suitable parking-floor and concrete construction applications within its technical documentation and provides documented wear and abrasion resistance.

Technical Data Sheet:
ChemSeal 1® TDS

However, the fact that a joint is located in a concrete floor does not automatically confirm product suitability.

Expected movement, joint geometry, concrete condition, traffic, exposure, and application requirements should still be checked before specification.

Parking-floor joints combine movement with mechanical exposure.

A suitable sealing system may need to accommodate opening and closing of the joint while also performing under conditions involving:

• Vehicle traffic

• Abrasion

• Water

• Dirt and contaminants

• Cleaning procedures

• Impact near joint edges

• Temperature changes

Key selection factors include:

• Joint movement

• Joint width and depth

• Concrete condition

• Traffic intensity

• Abrasion exposure

• Water or moisture

• Cleaning conditions

• Joint-edge condition

• Application and curing requirements

ChemSeal 1® includes parking-floor applications within its documented uses and provides wear and abrasion resistance.

Technical Data Sheet:
ChemSeal 1® TDS

Its suitability should still be confirmed against the actual project conditions rather than selected solely because the joint is located in a parking area.

Precast concrete elements can experience movement at the interfaces between adjacent components due to temperature changes, structural behavior, tolerances, and service conditions.

A suitable sealant must accommodate the designed joint movement while maintaining appropriate adhesion and environmental protection.

Important considerations include:

• Expected panel movement

• Joint width and depth

• Concrete surface condition

• Adhesion

• Weather exposure

• UV exposure

• Water ingress

• Joint orientation

• Backing material

• Primer requirements

ChemSeal 1® includes precast concrete panel applications within its technical documentation and provides documented UV and weather resistance.

Technical Data Sheet:
ChemSeal 1® TDS

Correct surface preparation and joint geometry remain essential even when the sealant technology is technically suitable.

Façade and exterior joints can experience repeated movement and environmental exposure throughout the service life of a building.

Typical conditions may include:

• UV radiation

• Rain

• Temperature cycling

• Wind-driven moisture

• Thermal movement

• Different adjacent façade materials

When selecting a sealant for an exterior or façade joint, evaluate:

• Expected movement

• Joint width and depth

• Façade substrate

• Adhesion requirements

• UV resistance

• Weather resistance

• Water exposure

• Vertical application characteristics

• Backing and primer requirements

• Compatibility with adjacent materials

ChemSeal 1® includes suitable façade-related applications and provides documented weather and UV resistance.

Technical Data Sheet:
ChemSeal 1® TDS

The complete façade joint detail should still be evaluated because the sealant is only one component of the building-envelope system.

Vertical joints place specific demands on the application behavior of a sealant.

The material must remain within the required joint profile rather than sagging excessively during installation or curing.

Selection should consider:

• Joint dimensions

• Movement

• Substrate

• Product consistency

• Application temperature

• Mixing requirements

• Primer

• Backing material

• Environmental exposure

ChemSeal PS® is formulated as a two-component non-sag polysulphide joint sealant for suitable vertical and horizontal construction joints.

Technical Data Sheet:
ChemSeal PS® TDS

Suitable polyurethane systems may also be considered where their documented characteristics meet the project requirements.

Joint orientation should therefore be treated as one selection factor—not the only one.

Horizontal construction joints may experience a different combination of service conditions from vertical joints.

Depending on the project, these can include:

• Traffic

• Abrasion

• Standing or intermittent water

• Dirt accumulation

• Cleaning operations

• Mechanical exposure

• Chemical contact

• Temperature changes

Potential iChem solutions may include:

• ChemSeal 1®

• ChemSeal PU®

• ChemSeal PS®

• ChemJoint®

The correct product depends on the substrate, movement, dimensions, exposure, traffic, and required service performance.

Technical Data Sheets

• ChemSeal 1® TDS

• ChemSeal PU® TDS

• ChemSeal PS® TDS

• ChemJoint® TDS

The description “horizontal joint” alone is not sufficient for final specification.

Chemical exposure requires more detailed evaluation than simply identifying a product as “chemical resistant.”

The exact exposure should be defined before product selection.

Important questions include:

• Which chemical will contact the joint?

• What concentration is expected?

• At what temperature will exposure occur?

• Is exposure occasional or continuous?

• How long will contact last?

• Are additional cleaning chemicals used?

• Will the joint also experience movement?

• Are water or other contaminants also present?

ChemSeal PS® provides documented resistance to specified chemical exposure and may be considered where those characteristics correspond to the actual project environment.

Technical Data Sheet:
ChemSeal PS® TDS

The specific chemical environment should always be checked against the current product documentation before specification.

Joints exposed to seawater may require resistance characteristics beyond those needed for ordinary weather exposure.

Selection should consider:

• Joint movement

• Substrate

• Joint geometry

• Exposure frequency and duration

• Environmental conditions

• Adjacent construction materials

• Required service life

• Additional chemical or mechanical exposure

ChemSeal PS® provides documented seawater resistance and can be evaluated for suitable construction joints exposed to these conditions.

Technical Data Sheet:
ChemSeal PS® TDS

Seawater resistance alone does not confirm suitability for every marine or water-related application.

The complete joint design and project conditions should still be evaluated.

Asphalt and pavement joints can require a different sealing approach from typical façade or precast concrete joints.

Important factors include:

• Asphalt or concrete substrate

• Joint function

• Movement

• Joint geometry

• Traffic

• Temperature exposure

• Mechanical conditions

• Compatibility with surrounding pavement or waterproofing materials

ChemJoint® is a single-component, cold-applied bituminous jointing and sealing compound intended for suitable concrete, asphalt, pavement, flooring, and related construction applications.

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
ChemJoint® TDS

Because ChemJoint® uses bituminous technology, it should be evaluated according to substrate and system compatibility rather than treated as a direct substitute for polyurethane or polysulphide sealants.

Water-channel applications require evaluation of more than the presence of water.

The joint detail may also need to account for:

• Joint movement

• Concrete condition

• Joint width and depth

• Water exposure

• Adjacent waterproofing

• Installation environment

• Required durability

ChemJoint® includes canals and water-channel applications within its technical documentation.

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
ChemJoint® TDS

The selected sealing system should form part of the complete construction and waterproofing detail rather than being treated as an isolated material.

A reliable movement joint often depends on more than the exposed sealant.

Depending on the joint design, a complete joint may include:

Joint Substrate → Joint Filler → Backer Rod or Bond-Breaking Layer → Sealant

Each component performs a different function.

The correct combination depends on:

• Joint design

• Joint dimensions

• Expected movement

• Sealant geometry

• Substrate

• Product requirements

• Project specification

A backer rod is a compressible backing material positioned behind the sealant in suitable joint designs.

Its primary role is not simply to fill empty space.

Depending on the system, a backer rod can help:

• Control sealant depth

• Support the required sealant profile

• Reduce unnecessary sealant consumption

• Prevent undesirable adhesion at the bottom of the joint

• Support appropriate movement behavior

The backer rod should be selected according to:

• Joint width

• Required installation depth

• Material compatibility

• Compressibility

• Sealant system

• Project detail

Incorrect selection or installation can affect the geometry of the sealant.

Sealant performance is influenced by the geometry of the installed material.

A common misconception is that applying a deeper sealant bead automatically creates a stronger or more durable joint.

This is not necessarily true.

Excessive or insufficient sealant depth can alter the way stresses develop within the material as the joint moves.

The correct depth should therefore follow the requirements of the exact product and joint design.

Where required, an appropriate backer rod can help establish and maintain this profile.

iFlex RS® is a closed-cell extruded polyethylene sheet used for suitable joint filling and backing applications.

It is not a liquid joint sealant and should not be treated as an alternative to polyurethane, polysulphide, or bituminous sealing compounds.

Instead, iFlex RS® can form part of the overall joint system where a compressible filler or backing material is required.

Relevant selection factors include:

• Joint dimensions

• Required filler thickness

• Compressibility

• Joint configuration

• Water exposure

• Compatibility with adjacent materials

• Project specification

iFlex RS® Technical Resources

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
Download iFlex RS® Technical Data Sheet

The role of iFlex RS® is different from the exposed joint sealant:

Joint filler/backing material → supports or occupies part of the joint

Joint sealant → creates the flexible exposed sealing zone

The exact arrangement should follow the joint design, project specification, and technical requirements of the selected materials.

In many movement-joint details, the sealant is intended to adhere to the two opposing joint faces rather than bonding to both side walls and the bottom of the joint.

This allows the sealant to deform more effectively as the joint opens and closes.

If the material bonds to three surfaces, the additional restraint can alter the stress distribution within the sealant.

This may increase the risk of:

• Excessive stress

• Internal tearing

• Adhesive failure

• Reduced movement performance

Where required by the joint design, an appropriate backer rod or bond-breaking material can help establish the intended bonding configuration.

Product-specific installation guidance should always take priority.

Even a correctly selected expansion joint sealant can perform poorly if it is applied to an unsuitable surface.

Joint faces should be prepared according to the requirements of the selected product and substrate.

Potential contaminants or weak materials may include:

• Dust

• Dirt

• Oil

• Grease

• Laitance

• Loose particles

• Weak concrete

• Previous sealant residues

• Incompatible coatings

• Curing compounds

• Moisture outside the permitted application conditions

The objective is not simply to make the joint look clean.

The objective is to provide a sound and technically suitable bonding surface for the selected sealant system.

No.

Primer requirements are product- and substrate-specific.

The correct question is not:

“Does every expansion joint sealant need a primer?”

The better question is:

“Does this specific sealant require a primer on this substrate under these application conditions?”

Primer requirements can depend on:

• Sealant chemistry

• Substrate type

• Surface condition

• Moisture conditions

• Application environment

A primer should not automatically be added or omitted by assumption.

Follow the current Technical Data Sheet and installation guidance for the selected product.

A durable expansion joint should be approached as a system decision, not simply as the selection of a sealant cartridge.

A practical technical sequence is:

Joint Function → Expected Movement → Joint Geometry → Substrate → Surface Preparation → Backing / Filler → Primer → Sealant → Application → Curing → Inspection → Maintenance

Each decision affects the next.

A technically suitable sealant can still perform poorly if:

• Joint movement is underestimated

• Geometry is incorrect

• Substrate preparation is poor

• Backing is unsuitable

• Primer requirements are ignored

• Installation conditions are outside the product limits

The objective is therefore not simply to create a joint that looks sealed on the day of installation.

The objective is to create a joint sealing system whose design, materials, and installation are appropriate for the movement and service conditions it is expected to experience.

Selecting the right expansion joint sealant is only one part of achieving a durable joint.

Even a technically suitable product can underperform if the joint is poorly prepared, the sealant geometry is incorrect, the backing material is unsuitable, or application takes place outside the conditions specified for the product.

A reliable installation process should therefore address the complete joint—not only the application of the sealant.

The following steps provide a practical framework. Product-specific instructions in the current Technical Data Sheet and project specification should always take priority.

Before preparing or filling the joint, inspect the actual site condition.

Confirm:

• Joint type and intended function

• Actual joint width and depth

• Condition of the joint edges

• Substrate type and condition

• Existing contamination

• Moisture conditions

• Previous sealant or filler materials

• Expected movement

• Required backing material

• Primer requirements

• Accessibility for application

Do not assume that the joint dimensions or conditions on site are identical to the original design.

Cracked edges, weak concrete, unexpected movement, incompatible existing materials, or damaged substrates may require investigation before resealing.

Applying fresh sealant over an unresolved joint problem may temporarily cover the defect without correcting its cause.

Where an existing joint is being repaired or resealed, failed materials should be assessed before the new system is installed.

Depending on the condition of the joint, removal may include:

• Failed sealant

• Loose filler

• Weak substrate material

• Dirt and debris

• Incompatible coatings

• Previous sealant residues

• Other bond-breaking contamination

The objective is to expose suitable joint faces for the new sealing system without unnecessarily damaging the surrounding substrate.

Surface preparation is critical to sealant adhesion.

Joint faces should be sound, clean, and prepared according to the requirements of the selected product.

Potential contaminants include:

• Dust

• Dirt

• Oil

• Grease

• Laitance

• Loose particles

• Weak concrete

• Curing compounds

• Old incompatible sealant residues

• Moisture outside the permitted product conditions

A high-performance sealant cannot compensate for a poorly prepared substrate.

The objective of surface preparation is therefore not simply to create a visually clean joint.

The objective is to provide a suitable bonding surface for the selected sealant system.

Before installing the backing material or applying the sealant, verify the actual joint dimensions.

Sealant depth should not be determined by simply filling the full depth of the opening.

The installed sealant should follow the geometry recommended for the exact product.

For example, ChemSeal 1® provides product-specific joint geometry guidance, including a generally recommended 2:1 width-to-depth relationship for applicable joint dimensions, with specific exceptions.

Technical Data Sheet:
ChemSeal 1® TDS

Never copy the joint geometry specified for one product and automatically apply it to another.

Where required by the joint design, install the specified backer rod, filler, or other backing material before sealant application.

Correct backing can help:

• Control sealant depth

• Establish the intended joint profile

• Support the sealant during application

• Reduce unnecessary sealant consumption

• Help prevent unwanted adhesion to the base of the joint

The backing material should be:

• Compatible with the sealant

• Suitable for the joint dimensions

• Correctly positioned

• Installed without unnecessary damage

Where a sheet-form joint filler or backing material is required, iFlex RS® may form part of suitable joint details.

Technical Data Sheet:
iFlex RS® TDS

Primer requirements vary between products, substrates, and application conditions.

Primer should not automatically be applied to every joint.

It should also not automatically be omitted.

Before application, verify:

• Whether a primer is required

• Which primer is compatible

• Which substrates require priming

• Required application method

• Drying or waiting time

• Application limitations

Incorrect primer selection or application can affect adhesion.

The current Technical Data Sheet for the selected sealant should determine the correct approach.

Different joint sealant technologies require different preparation procedures.

One-Component Polyurethane Sealants

ChemSeal 1® and ChemSeal PU® are one-component polyurethane systems.

They do not require the same two-component mixing procedure used for polysulphide systems.

However, their product-specific requirements for substrate condition, application temperature, joint dimensions, tooling, and curing should still be followed.

Technical Data Sheets:

• ChemSeal 1® TDS

• ChemSeal PU® TDS

Two-Component Polysulphide Sealant

ChemSeal PS® is a two-component polysulphide system.

Correct mixing is therefore an important part of preparation.

Incomplete or incorrect mixing can affect application and performance.

Follow the current product instructions for:

• Mixing procedure

• Component combination

• Application time

• Installation conditions

Technical Data Sheet:
ChemSeal PS® TDS

Cold-Applied Bituminous Joint Sealant

ChemJoint® is a single-component, cold-applied bituminous jointing and sealing compound.

It does not require heating or two-component mixing before use.

Its substrate, joint, and application requirements should still be verified before installation.

Technical Data Sheet:
ChemJoint® TDS

Apply the prepared sealant according to the required joint profile and product instructions.

The objective is to create a continuous sealing zone with appropriate contact to the prepared joint faces.

Avoid:

• Gaps

• Voids

• Air entrapment

• Incomplete contact with joint faces

• Irregular sealant depth

• Excessive material

• Insufficient material

• Contamination during application

For vertical applications, the product should also have application characteristics suitable for the orientation and joint dimensions.

Where required by the selected system, tooling helps establish the specified sealant profile and contact with the joint surfaces.

The finished joint should be:

• Continuous

• Consistent

• Properly positioned

• Installed to the required geometry

A smooth-looking bead does not automatically mean that the joint has been installed correctly.

Performance also depends on:

• Adhesion

• Depth

• Width

• Backing

• Bonding configuration

• Joint geometry

Fresh sealant may require protection before it reaches the condition required for service.

Depending on the product and project, protection may be required from:

• Vehicle or pedestrian traffic

• Water

• Dust

• Chemical exposure

• Mechanical disturbance

• Site contamination

• Unsuitable temperatures

• Other construction activities

Curing and return-to-service requirements should be taken from the current Technical Data Sheet for the selected product.

Joint sealant problems are not always caused by poor material quality.

Many failures result from product selection, joint design, surface preparation, application, or service conditions.

Avoiding the following mistakes can significantly improve the reliability of a joint sealing system.

“Polyurethane,” “polysulphide,” and “bituminous” describe technologies.

They do not provide enough information for final product selection.

Two polyurethane sealants may differ in:

• Movement capability

• Intended applications

• Joint geometry

• Exposure resistance

• Application requirements

Always evaluate the exact product.

A flexible sealant still has movement limits.

If the actual opening and closing of the joint exceeds the documented capability of the material, failure can occur even if the initial installation appears satisfactory.

Determine expected movement before final specification.

More sealant is not automatically better.

Incorrect depth can change how stresses develop inside the material during joint movement.

Follow the product-specific joint geometry recommendations.

Adhesion depends on the joint faces.

Dust, laitance, weak concrete, loose material, oil, grease, and other contamination can create a weak bonding interface.

Surface preparation should therefore be considered a technical installation requirement—not a cosmetic step.

Incorrect or missing backing can affect:

• Sealant depth

• Joint profile

• Material consumption

• Bonding configuration

• Movement behavior

Where backing is required, control its:

• Type

• Size

• Compatibility

• Installation depth

In movement-joint designs intended for two-sided adhesion, bonding the sealant to both side walls and the bottom of the joint creates additional restraint.

This can change how the material responds to movement.

Where required, use an appropriate backer rod or bond-breaking material to establish the intended bonding configuration.

Additional primer does not automatically produce better adhesion.

Primer use should follow the technical requirements of the sealant, substrate, and application environment.

The opposite assumption can also create problems.

Where the selected system requires primer, omitting it may affect adhesion.

Always follow the exact product documentation.

A sealant suitable for ordinary exterior weather conditions may not be appropriate for a demanding chemical environment.

Before specification, determine:

• Chemical type

• Concentration

• Temperature

• Frequency

• Exposure duration

Where relevant, also consider seawater, cleaning chemicals, fuels, oils, and other contaminants.

ChemSeal 1® and ChemSeal PU® both use polyurethane technology.

That does not mean they should automatically be substituted for one another.

Product-specific technical properties and intended applications should determine selection.

Technical Data Sheets:

• ChemSeal 1® TDS

• ChemSeal PU® TDS

Temperature, substrate moisture, weather, and curing conditions can influence installation.

A technically suitable material applied under unsuitable conditions can still perform poorly.

Vehicle traffic, pedestrian traffic, water, chemical contact, or physical disturbance before adequate curing can interfere with the new joint seal.

Follow the specified curing and return-to-service requirements for the product.

Expansion joint sealant failure often indicates a problem somewhere within the joint system rather than automatically proving that the sealant itself is defective.

Potential causes include:

• Movement beyond the sealant's capability

• Incorrect joint geometry

• Poor surface preparation

• Adhesion loss

• Incorrect backing

• Unwanted three-sided adhesion

• Unsuitable substrate

• Incorrect primer use

• Application outside specified conditions

• Chemical incompatibility

• Water-related deterioration

• Mechanical damage

• Damaged joint edges

• Ageing

• Failure in adjacent waterproofing or construction

The visible failure pattern can provide valuable information about the underlying cause.

Two common failure modes are adhesive failure and cohesive failure.

Understanding the difference is useful during joint investigation.

Adhesive failure occurs when the sealant loses its bond with one or both joint faces.

The sealant may pull away from the substrate while the main body of the bead remains relatively intact.

Possible contributing factors include:

• Inadequate surface preparation

• Dust or loose particles

• Oil or grease

• Weak substrate

• Incorrect or missing primer where required

• Incompatible substrate

• Moisture conditions outside product limits

• Contamination from previous materials

• Excessive joint movement

• Incorrect application

The failed interface should be examined before resealing.

Simply applying new material over an adhesion failure may not correct the underlying problem.

Cohesive failure occurs within the body of the sealant rather than at the sealant-to-substrate interface.

The material may tear or split while portions remain attached to both joint faces.

Possible contributing factors include:

• Movement beyond the material's capability

• Excessive deformation

• Incorrect joint geometry

• Material deterioration

• Mechanical damage

• Service conditions beyond the intended performance

• Application problems

This distinction can help identify whether the investigation should focus primarily on the bonding interface or on the sealant profile and service conditions.

Repeated sealant failure should trigger a broader investigation.

Removing failed material and installing the same product in the same way may reproduce the same problem if the underlying condition remains unresolved.

Before resealing a repeatedly failing joint, investigate:

1. Actual joint movement

2. Joint width and depth

3. Joint-edge condition

4. Substrate condition

5. Previous sealant type

6. Failure pattern

7. Backing material

8. Primer history

9. Water or chemical exposure

10. Traffic or mechanical damage

11. Previous installation conditions

12. Suitability of the proposed replacement system

Repeated failure is a reason to investigate the joint system—not simply apply more sealant.

Sealant pulling away from concrete is commonly associated with adhesion failure.

Possible causes include:

• Dust

• Laitance

• Oil or grease

• Weak concrete

• Previous material residues

• Inadequate surface preparation

• Incorrect primer use

• Moisture conditions

• Substrate incompatibility

• Excessive movement

• Incorrect joint geometry

The failed joint faces should be evaluated before selecting the repair procedure.

Cracking or tearing can occur when the installed material is exposed to movement or service conditions outside those anticipated for the joint system.

Potential causes include:

• Movement exceeding sealant capability

• Incorrect width-to-depth ratio

• Unwanted three-sided adhesion

• Material deterioration

• Mechanical damage

• Incorrect product selection

• Application problems

• Environmental or chemical exposure beyond the system capability

The location and pattern of the damage can help distinguish between adhesive and cohesive failure.

Sealant sagging in a vertical joint can indicate that the material, joint dimensions, mixing, or installation conditions are unsuitable.

Possible contributing factors include:

• Incorrect product consistency

• Excessive application thickness

• Incorrect mixing of a multi-component product

• Application outside specified conditions

• Incorrect joint geometry

• Installation technique

ChemSeal PS® is formulated as a two-component non-sag polysulphide sealant for suitable vertical and horizontal construction joints.

Technical Data Sheet:
ChemSeal PS® TDS

Product suitability should still be verified against the exact joint conditions.

Water leakage does not automatically mean that the visible sealant is the original point of entry.

Possible causes include:

• Loss of adhesion

• Cracks or tears

• Incomplete sealant application

• Damaged joint edges

• Incorrect joint detailing

• Movement beyond system capability

• Adjacent waterproofing failure

• Nearby cracks

• Penetrations

• Drainage problems

• Connections to other building-envelope components

Water can travel through construction details and become visible at a location different from the actual entry point.

For this reason, leakage investigation should consider the complete construction and waterproofing system, not only the exposed sealant.

This table is intended to identify useful starting points for investigation.

A visible symptom should not be treated as a definitive diagnosis without evaluating the complete joint condition.

Routine inspection can help identify deterioration before it develops into a more significant joint problem.

Look for:

• Loss of adhesion

• Cracks

• Tears

• Missing sealant

• Sagging

• Hardening or visible deterioration

• Damaged joint edges

• Excessive compression

• Excessive extension

• Water staining

• Traffic damage

• Debris accumulation

• Unexpected changes in joint width

Where deterioration is identified, determine whether the problem is:

• Localized or continuous

• Associated with movement

• Associated with water

• Related to substrate failure

• Related to mechanical damage

• Repeated from a previous repair

This information can help determine whether the appropriate response is a local repair or a broader investigation of the joint system.

There is no single maintenance interval that applies to every sealed joint.

Inspection frequency should reflect the importance and exposure of the application.

Joints may require closer attention where they are exposed to:

• Heavy traffic

• Exterior weather

• Significant thermal movement

• Chemical exposure

• Water or seawater

• Critical waterproofing conditions

• Previous joint failures

Maintenance should consider not only the sealant but also:

• Joint edges

• Surrounding substrate

• Backing condition where accessible

• Adjacent waterproofing

• Drainage

• Nearby cracks or damage

Where repair is required, the cause of deterioration should be investigated before the replacement material is selected.

Replacing failed sealant without addressing the underlying cause can lead to repeated failure.

An expansion joint sealant is used to create a flexible seal within a movement joint while allowing adjacent building elements to expand and contract.

It can help:

• Accommodate specified joint movement

• Limit water ingress

• Reduce the entry of dust and contaminants

• Maintain a flexible seal between adjacent surfaces

• Protect the joint from relevant environmental exposure

Expansion joint sealants are used in applications such as concrete movement joints, floors, precast concrete, façades, parking areas, pavements, and suitable vertical or horizontal construction joints.

The correct product depends on the actual movement, substrate, joint geometry, exposure, and service conditions.

There is no single best sealant for every expansion joint.

The correct choice depends on:

• Expected movement

• Joint width and depth

• Substrate

• Joint orientation

• Water or chemical exposure

• UV and weather conditions

• Traffic

• Mechanical exposure

• Required service performance

Within the iChem range, different technologies address different requirements:

• ChemSeal 1® — polyurethane joint sealant with a stated ±25% movement capability

• ChemSeal PU® — one-component moisture-curing polyurethane sealant

• ChemSeal PS® — two-component polysulphide joint sealant with a stated ±50% movement factor

• ChemJoint® — cold-applied bituminous joint sealing compound for compatible applications

Technical Data Sheets

• ChemSeal 1® TDS

• ChemSeal PU® TDS

• ChemSeal PS® TDS

• ChemJoint® TDS

Polyurethane and polysulphide sealants can both be suitable for concrete expansion and movement joints when their documented properties match the project requirements.

For example:

• ChemSeal 1® may be considered where its movement capability, joint geometry, weather resistance, abrasion resistance, and intended applications match the project.

• ChemSeal PU® may be considered for suitable expansion and contraction joints.

• ChemSeal PS® may be relevant where higher documented movement capability or demanding environmental exposure is required.

Concrete alone should never be the only selection criterion.

Polyurethane and polysulphide sealants are different technologies with different technical characteristics.

In the iChem range:

• ChemSeal 1® and ChemSeal PU® are polyurethane-based.

• ChemSeal PS® is a two-component polysulphide sealant.

Selection should compare:

• Movement capability

• Joint geometry

• Substrate

• Application requirements

• Environmental exposure

• Chemical exposure

• Service conditions

The chemistry should help guide selection, but the final decision should be based on the exact product documentation and project requirements.

No.

A higher movement value can be useful when the project requires greater joint movement, but it does not automatically make the product better for every application.

For example:

• ChemSeal 1® has a stated movement capability of ±25%.

• ChemSeal PS® has a stated movement factor of ±50%.

The final selection must still consider:

• Substrate

• Joint dimensions

• Exposure

• Application conditions

• Orientation

• Service environment

Movement capability is one technical parameter—not the complete specification.

A backer rod is commonly used where the joint design requires controlled sealant depth and a specific bonding configuration.

A suitable backer rod can help:

• Control sealant depth

• Support the required joint profile

• Reduce unnecessary sealant consumption

• Prevent unwanted adhesion to the bottom of the joint

Whether a backer rod is required depends on the sealant system, joint dimensions, and project detail.

A backer rod is typically used directly behind the sealant to help control depth and support the required sealant profile.

A joint filler may occupy a larger part of the joint and provide separation, filling, or compressible support.

They can form part of the same joint system, but they do not necessarily perform the same function.

iFlex RS® is a closed-cell extruded polyethylene sheet used for suitable joint filling and backing applications.

It is not a liquid joint sealant.

It can form part of a complete expansion joint detail where a compressible filler or backing material is required.

Technical Data Sheet:
iFlex RS® TDS

Sealant depth should be determined from:

• Joint design

• Joint width

• Product-specific geometry

• Backing material

• Technical Data Sheet requirements

A deeper sealant bead is not automatically better.

For example, ChemSeal 1® provides product-specific geometry guidance including a generally recommended 2:1 width-to-depth relationship for applicable joint dimensions.

Technical Data Sheet:
ChemSeal 1® TDS

The geometry specified for one product should not automatically be transferred to another.

Yes, where the selected product is suitable for the orientation and application requirements.

For vertical joints, the material must maintain the required profile during application and curing.

ChemSeal PS® is formulated as a two-component non-sag polysulphide sealant for suitable vertical and horizontal construction joints.

Technical Data Sheet:
ChemSeal PS® TDS

ChemSeal 1® includes parking-floor applications within its technical documentation and provides documented wear and abrasion resistance.

However, parking-floor selection should still consider:

• Joint movement

• Traffic

• Abrasion

• Concrete condition

• Joint geometry

• Water exposure

• Application requirements

Technical Data Sheet:
ChemSeal 1® TDS

ChemSeal PS® provides documented resistance to relevant chemical exposure, seawater, and weathering.

The actual service conditions should still be defined before specification.

Check:

• Chemical type

• Concentration

• Temperature

• Exposure duration

• Frequency

• Joint movement

• Substrate

Technical Data Sheet:
ChemSeal PS® TDS

ChemJoint® is a cold-applied bituminous joint sealing compound intended for compatible applications including concrete, asphalt, flooring, and pavements.

Selection should focus on:

• Substrate compatibility

• Joint function

• Surrounding pavement or waterproofing system

• Service conditions

• Application requirements

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
ChemJoint® TDS

Sealant pulling away from concrete is commonly associated with adhesion-related problems.

Possible causes include:

• Dust

• Laitance

• Weak concrete

• Oil or grease

• Incorrect surface preparation

• Primer problems

• Moisture conditions

• Incompatible materials

• Excessive joint movement

The failed joint faces should be investigated before resealing.

Repeated failure often indicates that the underlying joint conditions have not been correctly identified.

Before resealing, investigate:

• Actual movement

• Joint dimensions

• Substrate condition

• Joint edges

• Backing material

• Primer history

• Exposure

• Previous installation

• Failure pattern

Replacing the material without correcting the underlying cause may reproduce the same failure.

No.

A correctly designed and installed sealant can help limit water ingress, but leakage may also involve:

• Adjacent cracks

• Failed waterproofing

• Damaged joint edges

• Drainage problems

• Penetrations

• Connections to other construction details

Water can travel through the structure and appear at a location different from the original entry point.

The complete waterproofing detail may therefore need to be investigated.

Technical product selection should be supported by the current documentation for the exact product.

One-component polyurethane joint sealant for suitable movement, connection, parking-floor, precast concrete, façade-related, and other compatible construction applications.

Product Page:
ChemSeal 1® Product Page

Technical Data Sheet:
ChemSeal 1® TDS

One-component moisture-curing polyurethane sealing compound for suitable expansion, contraction, vertical, horizontal, and flexible construction joint applications.

Product Page:
ChemSeal PU® Product Page

Technical Data Sheet:
ChemSeal PU® TDS

Two-component non-sag polysulphide sealant for suitable vertical and horizontal construction joints and demanding exposure conditions.

Product Page:
ChemSeal PS® Product Page

Technical Data Sheet:
ChemSeal PS® TDS

Single-component, cold-applied bituminous jointing and sealing compound for compatible concrete, asphalt, pavement, flooring, water-channel, and related construction applications.

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
ChemJoint® TDS

Closed-cell extruded polyethylene sheet for suitable joint filling and backing applications.

Product Range:
View iChem Joint Sealant Solutions

Technical Data Sheet:
iFlex RS® TDS

Joint sealant selection requires more than identifying a material as polyurethane, polysulphide, or bituminous.

Engineers, consultants, contractors, and applicators need product-specific technical information that allows the proposed system to be evaluated against actual project conditions.

iChem provides joint sealing and joint filling solutions based on different technologies, supported by product-specific technical documentation.

The selection process should consider the complete system:

Joint Design → Movement → Geometry → Substrate → Exposure → Backing → Sealant Technology → Application → Technical Verification

This approach helps ensure that product selection is based on documented project requirements rather than a generic material description.

Every project has different joint conditions.

A sealant suitable for a parking floor may not be the right solution for a chemically exposed joint.

A material suitable for concrete may not automatically be appropriate for asphalt or a bituminous waterproofing system.

Even two polyurethane sealants can have different technical requirements and intended applications.

For technical product evaluation, provide as much project information as possible, including:

• Joint type

• Joint width and depth

• Expected movement

• Substrate

• Horizontal or vertical orientation

• Water exposure

• Chemical exposure

• UV and weather exposure

• Traffic conditions

• Required service performance

• Available drawings or specifications

Contact iChem Technical Support to discuss the appropriate joint sealing solution for your project.

Choosing the right expansion joint sealant starts with the joint requirements—not the product name.

The correct solution depends on the relationship between:

Movement → Geometry → Substrate → Exposure → Application → Service Conditions

Polyurethane systems such as ChemSeal 1® and ChemSeal PU®, polysulphide technology such as ChemSeal PS®, and bituminous solutions such as ChemJoint® address different construction requirements.

Joint filling and backing materials such as iFlex RS® can also form part of the complete joint system where required.

The most reliable selection process is therefore to:

Define the joint → Evaluate movement and geometry → Identify the substrate and exposure → Select the appropriate technology → Verify the current Technical Data Sheet → Confirm the complete joint system

Final product selection should always follow the project specification and the current technical documentation for the exact material being considered.