How are the structural airtightness and thermal performance of prefabricated houses guaranteed?
Publish Time: 2026-01-22
Against the backdrop of increasing demand for green buildings and rapid construction, prefabricated houses have rapidly developed due to their advantages such as factory production and efficient on-site assembly. However, their performance—especially structural airtightness and thermal performance—is often questioned as to whether it can match or even surpass traditional cast-in-place buildings. In fact, through precise design, advanced materials, and standardized processes, modern prefabricated houses not only effectively solve the problems of joint leakage and thermal bridging, but also set new benchmarks in energy saving, comfort, and durability.1. Factory Precision: Controlling Gaps and Deviations from the SourceTraditional on-site construction is affected by factors such as weather and worker skill, easily resulting in millimeter-level or even centimeter-level errors at wall and floor joints, leading to incomplete sealing and creating channels for water seepage and air leakage. In contrast, the core components of prefabricated houses are cast or assembled using CNC molds in a temperature- and humidity-controlled factory, with dimensional tolerances controlled within ±2mm. This millimeter-level precision allows components to fit together seamlessly during on-site hoisting, significantly reducing structural gaps and laying the foundation for high sealing performance.2. High-Performance Joint Treatment: Multiple Lines of Defense Against Wind and Rain InfiltrationThe key to sealing prefabricated houses lies in the design of the joint construction. Horizontal and vertical wall joints generally employ a triple protection system of "tongue-and-groove joint + elastic sealant + waterproof strip":The tongue-and-groove design forms a physical labyrinth, preventing direct rainwater intrusion;Compressible EPDM generates resilience after the components are compressed, maintaining long-term airtightness and watertightness;The weather-resistant silicone sealant on the outside provides a flexible seal, adapting to minor displacements without cracking.Furthermore, waterproof sleeves or integrated waterproof membranes are pre-embedded in detailed joints such as window openings and pipe penetrations, eliminating weak points. Prefabricated houses are far superior to conventional buildings, significantly reducing heating and cooling loads.3. Integrated Insulation System: Eliminating Thermal Bridges and Improving Energy EfficiencyThe core challenge in thermal performance lies in thermal bridging—high thermal conductivity paths such as metal connectors and concrete ribs that cause rapid localized heat loss. Modern precast walls commonly employ sandwich insulation structures: high-performance insulation material is filled between the inner and outer leaf wall panels. More importantly, non-metallic tie rods connecting the inner and outer leaves significantly reduce heat conduction. Some high-end systems even extend the insulation layer to the foundation and roof, achieving "full-coverage" continuous insulation and completely isolating thermal bridges.4. Synergistic Integration of Airtight Layer and Intelligent Ventilation: Balancing Health and Energy SavingWhile high airtightness reduces unorganized air leakage and improves insulation, it needs to be combined with a mechanical ventilation heat recovery system. Prefabricated houses can have duct interfaces pre-installed at the factory for quick on-site connection. MVHR (Multi-Voltage Heat Recovery System) recovers 70%–90% of the heat while exhausting stale air for preheating fresh air, ensuring indoor air quality and avoiding energy waste caused by opening windows. This "high airtightness + intelligent ventilation" model is the core of passive house standards and has been widely used in prefabricated houses in Northern Europe and Germany.5. Material and Process Synergy: Guaranteeing Long-Term PerformanceAll sealants, insulation boards, and waterproof membranes must pass aging resistance, UV resistance, and freeze-thaw cycle tests; over 80% of component joints are sealed before leaving the factory, reducing the uncertainty of on-site wet work. Simultaneously, BIM technology simulates heat flow and airflow paths throughout the process, optimizing node details.The airtightness and thermal performance of prefabricated houses are not inherent advantages, but rather the result of engineering achievements achieved through the deep integration of industrial precision, systematic construction, high-performance materials, and intelligent equipment. It proves that "speed" and "quality" can coexist—delivering more energy-efficient, comfortable, and durable living spaces while shortening construction time, providing a practical path for the low-carbon transformation of the construction industry.
