How to Insulate Prefabricated Houses

The insulation of prefabricated houses can be achieved through optimization of exterior walls, roofs, doors and windows, as well as specialized modular measures, requiring a combination of material selection and structural design to enhance overall performance.

Exterior Wall Insulation

Exterior walls are one of the main pathways for heat transfer and require structural design to reduce heat loss.

• Hanging-type exterior wall insulation: Insulation materials (such as polyurethane, extruded polystyrene boards, or polystyrene boards) are attached to the outer side of prefabricated exterior wall panels, forming a continuous thermal insulation layer through mechanical fastening or adhesives. This method is convenient for construction, but attention should be paid to the thermal bridge effect of fasteners, which can be mitigated by using thermal break anchors to reduce energy conduction.
• Insulation board plastering exterior wall insulation: Insulation boards (such as rock wool boards) are adhered to the surface of exterior wall panels, covered with anti-crack mortar and mesh fabric to enhance structural stability, and finally finished with a decorative treatment. This method combines insulation and fire resistance, making it suitable for scenarios with high durability requirements.

Roof Insulation

The roof is a critical area for heat loss and requires a composite structure that balances insulation and waterproofing.

• Insulation layer installation: Insulation materials (such as roof insulation boards) are installed beneath the roof, with priority given to materials with low thermal conductivity and strong resistance to snow loads (such as extruded polystyrene boards). The thickness of the insulation layer should be calculated based on local climate conditions to ensure that the thermal resistance value meets energy efficiency standards.
• Composite structural design: A layered structure of “insulation layer + waterproof layer + protective layer” is adopted, with the insulation layer located beneath the waterproof layer to prevent rainwater infiltration from degrading insulation performance; the protective layer (such as concrete slabs) protects the insulation layer from mechanical damage while enhancing overall roof stability.

Door and Window Design Optimization

Doors and windows are weak points for heat exchange and require material and sealing design improvements to enhance insulation performance.

• High-efficiency thermal insulation windows: Choose thermal break aluminum alloy or PVC window frames paired with Low-E glass (low-emissivity coated glass) to reduce heat transfer and radiation through the glass. Large prefabricated houses can adopt double- or multi-layer glass structures filled with inert gases (such as argon) between the panes to further improve thermal insulation performance.
• Enhanced sealing performance: Use expanding foam to fill gaps between doors, windows, and walls during installation, paired with sealing strips or brush seals to prevent cold air infiltration. Regularly inspect the aging condition of sealing strips and replace them promptly to maintain sealing effectiveness.

Special Measures for Modular Container Houses

Modular houses require targeted insulation solutions tailored to their spliced structure and steel framework characteristics.

• Wall insulation system optimization: Fill high-efficiency insulation materials (such as glass wool or rock wool) within the cavities of steel structural walls, while adding moisture-permeable and vapor-barrier layers to block water vapor infiltration, which can cause condensation issues and degrade insulation material performance when damp.
• Enhanced sealing performance: Use flexible sealing materials (such as silicone sealants) to fill gaps at module joints, door and window openings, and service penetration points, combined with mechanical fastening or sealant treatment to form a continuous sealing layer, preventing cold air infiltration through gaps.