Interior Wall Insulation for Container Houses

Interior wall insulation for container houses can use multiple materials and methods; common approaches include closed-cell insulation, spray insulation, and high-efficiency thermal materials.

Closed insulation methods

Closed insulation fills or bonds insulation into a continuous thermal layer, cutting heat conduction through walls. Rock wool is common: made from basalt melted into fibers, it has low thermal conductivity (about 0.03-0.04 W/(m·K)) and excellent fire performance (Class A non-combustible), suited to high fire requirements. Expanded perlite boards are pressed from expanded perlite granules; the porous structure blocks heat transfer and offers light weight and sound absorption, but moisture protection is needed so performance does not drop after water uptake.

Spray insulation

Spray insulation applies material directly to interior walls, flexibly covering complex shapes. Plaster materials (such as cement mortar with insulation granules) control performance by thickness but often need companion materials. Clay walls use clay’s thermal mass with straw and similar additives for better insulation—suited to ecological builds but longer to construct and humidity-sensitive. Wood-panel spray usually means spraying polyurethane foam onto wood boards for a decorative-plus-insulating layer; check wood–foam compatibility and fire treatment.

High-efficiency insulation materials

Polystyrene boards (EPS/XPS) use polystyrene foam with closed cells, low conductivity (about 0.028-0.035 W/(m·K)), and lower cost, but weaker fire rating (Class B), so fire breaks are needed. Polyurethane foam boards can be site-sprayed or installed as prefabricated panels for seamless insulation, with conductivity as low as 0.022 W/(m·K) and strong adhesion, but need professional equipment and cost more. Rock-wool boards resemble rock wool in closed systems but install as bonded boards—more convenient for fast retrofit.

Material selection tips

• Fire first: Choose Class A non-combustible rock wool / rock-wool boards, especially for public or multi-story container houses.
• Cost-sensitive: EPS/XPS or expanded perlite boards cost less; weigh fire and durability.
• Overall performance: Polyurethane foam boards excel in insulation and sealing for high energy-efficiency needs.
• Ecological needs: Clay walls or straw boards suit low-carbon builds but should match local climate.

During installation, keep insulation tight to the wall to avoid thermal bridges at gaps, and manage moisture to extend material life.