In large-scale construction projects, failures in window systems often result not solely from product defects but from coordination gaps among design, manufacturing, and on-site installation teams. Common issues such as water leakage, deformation, poor sealing, and hardware malfunction can be significantly minimized—or entirely avoided—when risk management begins at the design and pre-installation stages.

As a professional aluminum window and door manufacturer with extensive project experience, we have identified the root causes of recurring after-sales problems and outlined corresponding preventive measures that contractors and installers can implement during early-stage planning.

1. Water Leakage — Controlled by Structural Design and Effective Drainage

Water leakage remains one of the most frequent after-sales issues. Its root causes typically lie in insufficient drainage design, sealant deterioration, or improper joint treatment between the window frame and wall.

Common Causes and Engineering Solutions:

• Leakage at the sill or wall corner: Usually caused by an inadequate slope (inner side higher than outer), blocked drainage holes, or aged silicone sealant. → Ensure a minimum 5° outward slope at the sill, maintain clear drainage paths, and reapply exterior-grade silicone when necessary.

• Leakage from the upper frame: Often due to missing drip grooves or capillary infiltration through the concrete lintel. → Add a recessed drip groove below the lintel and reinforce the waterproof mortar layer.

• Side frame leakage: Commonly caused by voids between the frame and wall interface. → Clean the area, regrout with waterproof mortar, and reapply sealant properly.Drip line marked with red arrow: key detail for preventing water leakage in aluminum window installationsDrip line marked with red arrow: key detail for preventing water leakage in aluminum window installationsDrip line highlighted to prevent window leakageDrip line highlighted to prevent window leakageDrip line highlighted to prevent window leakage

Manufacturer Recommendation: Adopt a dual-chamber drainage design and conduct pre-delivery water-tightness testing. Provide installers with detailed section drawings and sealant specifications to ensure construction accuracy.

2. Sliding Windows — Ensuring Track Alignment and Airtight Performance

Sliding window systems depend heavily on structural precision and component compatibility. Frequent issues include sash derailment, air leakage, and operational stiffness.

Common Causes and Engineering Solutions:

• Sash derailment: Caused by frame settlement or insufficient sash overlap (<8 mm). → Verify track levelness and maintain an overlap of ≥8 mm.

• Air leakage: Usually the result of aged brush seals or deformed sash profiles. → Use UV- and weather-resistant EPDM or wool pile seals and schedule regular inspections.

• Frame distortion: Often caused by an uneven substrate or incorrect anchor placement. → Use setting blocks and apply even torque during installation.

Manufacturer Recommendation: Maintain factory tolerance within ±1 mm and provide an installation manual to ensure on-site dimensional accuracy.

3. Tilt-and-Turn Systems — Precision Hardware Adjustment is Essential

Tilt-and-turn systems are mechanically complex and require precise synchronization between the sash, hardware, and frame. Improper installation or adjustment can lead to sash sagging, handle misalignment, or air leakage.

Key Issues and Solutions:

• Sash sagging: Caused by misaligned locking points or hinge stress. → Adjust the striker plate and tilt arm to achieve a 3 mm upward lift on the sash.

• Air leakage or improper closure: Often the result of insufficient seal compression or incorrect placement of glass setting blocks. → Position blocks correctly to distribute the glass load evenly.

Manufacturer Recommendation: Provide calibration documents and on-site adjustment videos to assist installers in achieving precise fine-tuning.

4. Hardware and Surface Treatment — Small Components, Big Impact

Hardware and finishing quality directly affect the durability and appearance of window systems.

• Corrosion or scratching: Typically caused by chemical exposure or improper handling. → Use 304 or 316 stainless-steel screws depending on environmental conditions (316 recommended for coastal projects).

• Misaligned hardware: Repeated removal or incorrect positioning can weaken fixings. → Always use manufacturer-approved components and ensure accurate one-time installation.

Manufacturer Recommendation: All hardware should undergo salt spray and load testing. Ensure finish color and coating compatibility to improve long-term performance and aesthetic consistency.

Conclusion｜Proactive Control Outperforms Reactive Maintenance

After-sales service is not merely a repair process—it reflects how effectively risks were managed during the design and manufacturing stages.

For contractors, minimizing long-term maintenance costs depends on:

• Early communication and coordination with the window system supplier.

• Implementation of preventive installation details.

• Full utilization of manufacturer testing reports and technical documentation.

A well-coordinated workflow between manufacturer and installer ensures not only zero leakage but also long-term structural stability and energy efficiency throughout the building’s life cycle.