Building Facade Construction Joint Sealant | Waterproofing & Sealing Solutions

Different curtain wall systems have vastly different requirements for sealants; improper selection in actual projects can easily lead to issues such as water leakage and cracking. This article helps you quickly understand how to select reliable sealant solutions for various types of facades.

Curtain Wall Systems and Specific Sealing Requirements

While modern glass curtain walls enhance architectural aesthetics, they also demand higher sealing performance—particularly regarding long-term weatherability and structural safety.

Common Areas Requiring Sealing

Key locations include:

Connections between glass and aluminum frames
Joints between curtain wall frame sections
Junctions between floor slabs and horizontal beams
Applications in structural glazing systems

Key Performance Requirements

Compatibility with Glass and Aluminum

The sealant must bond effectively to both glass and aluminum. Neutral-cure silicone is generally recommended; it is safer and avoids corroding the metal.

Ability to Accommodate Structural Movement

Glass curtain walls undergo significant displacement due to temperature fluctuations, so the sealant requires sufficient elasticity.
A movement capability of at least ±25% is typically recommended; however, ±50% is more reliable for large panels or regions with extreme temperature variations.

Aesthetic Requirements

As part of the building's exterior, the sealant's color and application uniformity directly impact the overall visual effect; consequently, black or custom-colored products are usually selected.

Considerations for Structural Glazing

Such applications require specialized structural silicone products that have undergone performance verification and engineering certification—never use standard exterior wall sealants for structural glazing seals.

For example, the Tengyu TNS721 double glazing silicone sealant is a high-performance neutral silicone product suitable for sealing joints between glass and aluminum curtain wall components, meeting requirements for long-term weatherability and high movement capability.

Metal Panel Curtain Walls

Metal curtain wall systems are widely used in commercial and industrial buildings. However, due to the distinct properties of the materials involved, they impose higher demands on sealing performance—especially regarding long-term weatherability and structural stability.

Common Metal Panel Types

Aluminum Composite Materials (ACM / ACP)
Standing-seam metal roofing systems
Corrugated and ribbed metal panels
Perforated metal panels and rainscreen systems
Coated steel and aluminum panels

Key Sealing Challenges

Significant Thermal Expansion and Contraction

Metal materials are highly sensitive to temperature fluctuations; therefore, highly elastic sealants must be used, and joint dimensions must be properly designed.

Risk of Metal Corrosion

Certain sealant systems may react with specific metals, leading to corrosion issues.
For instance, acetoxy-cure silicone sealants may be unsuitable for materials like copper, brass, or zinc; thus, appropriate neutral-cure silicone sealants should be selected.

Surface Coating Compatibility

Incompatibility between the sealant and the coating can lead to adhesion failure; consequently, compatibility testing or the application of a primer is often required in actual projects.

For example, Tengyu TNS731 glazing neutral silicone sealant offers high elasticity and excellent compatibility with metals, making it suitable for the long-term sealing of joints in aluminum and steel curtain walls.

Precast Concrete Exterior Walls

Precast concrete exterior walls are widely used in commercial architecture due to their construction efficiency and structural stability. However, the complexity of joint configurations and significant dimensional variations place higher demands on the sealing system.

Common Joint Locations

Sealing for precast concrete exterior walls primarily focuses on the following areas:

Vertical joints between adjacent wall panels
Horizontal joints between floor levels
Connection points with the main structure
Perimeters of doors, windows, and other openings
Areas with architectural recesses, projections, and decorative moldings

Key Performance Requirements

Adhesion Compatibility with Concrete

Concrete surfaces are alkaline, and varying surface conditions can affect sealant adhesion.
Neutral-cure silicone or MS sealants are typically selected; however, priming may be necessary on certain dense or smooth concrete surfaces to ensure long-term stability.

Stain Resistance

Sealants must possess good resistance to staining (migration of constituents into the substrate), as failure to do so can compromise the overall aesthetic quality.

Ability to Accommodate Wide Joints

Joints between precast panels are typically wide (approx. 15–40 mm) and vary across projects; therefore, sealants require excellent movement capability and must be used correctly with backer materials to ensure a stable, long-term seal.

For example, Tengyu TM506 precast concrete joint sealant is suitable for sealing precast concrete joints, offering strong adhesion to concrete and excellent long-term movement accommodation.

Natural Stone

Stone curtain walls are high-end architectural facade systems that demand exceptional aesthetic integrity and long-term stability from sealing materials; improper selection can easily compromise the building's overall appearance.

Common Stone Types

Stones frequently used for facades include:

Granite slabs and tiles
Marble cladding
Limestone facade systems

Key Sealing Requirements

Stain Resistance (Critical Risk Factor)

Natural stone—particularly light-colored marble and limestone—is highly sensitive to staining.
Incompatible sealants can cause staining or discoloration, directly affecting the building's appearance.

Therefore, compatibility testing on actual stone samples is mandatory for real-world projects.

Color Matching Requirements

Sealants often require color matching to harmonize with the stone's texture and appearance.
High-end projects may even require custom color matching tailored to the specific type of stone used.

For instance, Tengyu TNS731 neutral silicone sealant is specifically designed for sensitive stones like marble and limestone, effectively preventing staining and surface contamination.

EIFS and Stucco Facades

EIFS (Exterior Insulation and Finish Systems) and traditional stucco facades are widely used in commercial architecture.

Key Sealing Requirements

Compatibility with Foam Substrates

The insulation foam used in EIFS systems is highly sensitive to certain solvents or sealant ingredients; therefore, sealing products must be compatible with the EIFS system.

Joint Movement

EIFS systems experience continuous, slight movement, particularly around windows, doors, and expansion joints.

Sealants must accommodate the adhesion and deformation characteristics of diverse materials (foam substrates, window frames, metal, or other claddings).

Waterproofing System Integration

EIFS relies on an integrated moisture-resistant design; the sealing system must work in tandem with the waterproofing layer to prevent long-term water infiltration or performance degradation.

For instance, Tengyu TP680 polyurethane construction sealant is suitable for EIFS and stucco exterior wall systems, providing a reliable seal without compromising the insulation layer.

If you are currently selecting materials for a curtain wall project—or require sealant solutions tailored to specific exterior wall systems such as glass, metal, stone, concrete, or EIFS—we can provide product recommendations and application advice to help you complete the selection process more efficien