As a key component of the building waterproofing system, the firmness of the connection method of the waterproof backing board directly affects the overall waterproofing effect and service life. Common connection methods include mechanical fixation, adhesive bonding, welding, snap on connection, etc. Each method has its own advantages and disadvantages, and is suitable for different construction environments and material characteristics. The following will analyze in detail the process characteristics and stability comparison of these connection methods.

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1、 Mechanical fixed connection

Process characteristics:

Mechanical fixation is a method of fixing a backing plate to a substrate (such as concrete or steel structure) using metal parts such as screws, rivets, or pressure strips. Usually, it is necessary to use waterproof gaskets or sealants to prevent water leakage at fixed points.

Advantages:

1. High tensile strength: Suitable for scenarios with high wind pressure or external forces (such as curtain walls and roofs).

2. Convenient construction: Low requirements for the flatness of the base layer, suitable for large-scale and rapid installation.

3. Detachable: convenient for later maintenance or partial replacement.

Disadvantages:

1. Leakage risk: Fixed points may become weak links for water seepage and require additional sealing treatment.

2. Thermal bridge effect: Metal parts may cause thermal conduction, affecting insulation performance.

Stability comparison:

The anti pull performance of mechanical fixation (usually up to 1.5kN or above), but may become loose due to metal corrosion or seal aging during long-term use.

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2、 Adhesive connection

Process characteristics:

Stick the backing board onto the substrate using polyurethane, epoxy resin, or acrylic adhesive, ensuring that the substrate is clean and dry.

Advantages:

1. No perforation: avoids damaging the integrity of the backing board, and has better waterproof performance.

2. Adapt to complex shapes: Suitable for curved surfaces or irregular structures.

3. Shock absorption and buffering: The adhesive layer can absorb some stress and reduce the risk of cracking.

Disadvantages:

1. Dependence on the quality of the base layer: Loose, damp, or oily base layer will significantly reduce the bonding strength.

2. Long curing time: Pressure curing is required, and the construction period is relatively long.

Stability comparison:

The short-term bonding strength is relatively high (0.8~1.2kN), but long-term exposure to ultraviolet radiation and temperature differences may cause aging and delamination, especially in high temperature and high humidity environments where durability is poor.

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3、 Welding connection (hot air welding/ultrasonic welding)

Process characteristics:

Suitable for thermoplastic waterproof backing boards (such as PVC, TPO), which are melted by heating and pressed together.

Advantages:

1. Seamless integration: The weld strength is close to that of the base material, and it has waterproof properties.

2. Strong durability: anti-aging performance is better than adhesive bonding.

Disadvantages:

1. High equipment requirements: Professional welding machines and skilled workers are needed.

2. Material limitations: Only applicable to weldable synthetic polymer materials.

Stability comparison:

The tensile strength of the weld seam can reach more than 80% of the base metal (1.2-1.8kN), with long-term stability, but local overheating may lead to material embrittlement.

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4、 Snap on connection

Process characteristics:

The edge of the backing plate is prefabricated into a male and female mortise and tenon groove or buckle structure, which is fixed by interlocking and commonly used in lightweight waterproof systems.

Advantages:

1. Dry operation: No adhesive or welding required, environmentally friendly and fast construction.

2. Allowable displacement: Suitable for slight deformation of the base layer.

Disadvantages:

1. Weak wind resistance: It needs to be used in conjunction with mechanical fixation.

2. High precision requirements: Processing errors can easily lead to loose seams.

Stability comparison:

Low tensile strength (0.5~0.8kN), mostly used indoors or in low stress environments, requiring auxiliary fixing measures.

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5、 Other connection methods

1. Overlapping+sealant: Simple and economical, but relying on the durability of the sealant, it is prone to cracking due to shrinkage.

2. Magnetic connection: an emerging technology suitable for temporary waterproofing projects, with insufficient strength (<0.3kN).

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Comprehensive comparison of firmness (from high to low):

1. Welding connection: High strength and durability, but high cost and technical threshold.

2. Mechanical fixation: Strong pull-out resistance, attention should be paid to sealing and corrosion issues.

3. Adhesive bonding: The initial strength is good, but it is greatly affected by environmental factors in the long term.

4. Buckle type: Convenient but requires auxiliary reinforcement, suitable for low stress scenarios.

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Suggestion for selection:

-High stress environments (such as roofs and basements): prioritize welding or mechanical fixation+sealing.

-Wet base layer: When using adhesive bonding, it is necessary to cooperate with primer treatment.

-Quick construction: snap on or mechanical fixation is more efficient.

In short, the connection method of waterproof backing board needs to be selected comprehensively based on material characteristics, environmental conditions, and construction requirements. If necessary, it can be combined (such as welding+mechanical fixation) to improve overall reliability.