spouw

Spouw is a term used in architecture and construction to describe the hollow space between the inner and outer wall leaves in a cavity wall, or spouwmuur. The cavity serves to improve moisture management and thermal performance by separating the exterior surface from the interior finishing and providing room for insulation. It also helps to reduce heat loss and damp transfer from outside to inside.

In a typical spouwmuur, the outer leaf is a masonry facade such as brick or stone, while the inner leaf is usually plastered brick, concrete block, or another masonry material. The width of the cavity varies by climate and building codes but commonly ranges from about 50 to 100 millimeters. The leaves are connected by spouwankers or ties, which transfer horizontal loads between layers. Water that penetrates the outer leaf is drained through weep holes and the cavity is ventilated at the top and bottom to prevent condensation and mold growth.

Spouwisolatie refers to the installation of insulating material within the cavity to reduce heat loss. Common materials include mineral wool, expanded polystyrene or polyurethane boards, and other foam products. Proper installation is important to avoid gaps, thermal bridging, or moisture buildup, particularly around openings and lintels. In renovation work, attention to cavity integrity and ventilation remains essential to maintain the long-term performance of the wall.

Overall, the spouw is a key feature in modern construction for balancing energy efficiency with durable moisture control.