Cavity walls

Slot wall: a) cross-section through the wall in the place of the window opening, b) tying bricks in the corner of the cavity wall (the numbers indicate the sequence in which the layers are laid), c) various types of fasteners; 1 – plaster (rap), 2 – trough with slopes in both sides, 3 – cover, 4 -brickwork separated from the wall with an insulating layer, 5 – air gap 7 cm, 6 – wire connector 06, 7 – insulation with a slope to the outside, 8 – a connector made of a flat bar.

The simplest cavity wall consists of two walls with an air gap between them. These walls are used to increase thermal insulation of external walls, or as airtight partitions, which prevent seepage of water through external walls exposed to strong diagonal rains (Lynx. a).
Air closed in gaps improves the thermal insulation of the wall. Gaps 3-4 cm wide may run along the entire height of the storey, because their narrow width and the roughness of the wall surfaces impede the circulation of the air contained in them. When using slots with a width of 5-8 cm, their height should be limited to 50 cm. For this purpose, each 7 or 8 a layer of brick in the wall covers the gap along its entire length (rys.b).
Cavity walls can be made of either one material, or two; the outer wall can be made of ceramic brick that serves as a cladding, while the inner one can be made of elements with better thermal properties. Thermal bridges form in the places where the walls are bound with bricks, which worsen the thermal properties of the wall. The thermal insulation of the walls can be improved by filling the gaps with insulating material, e.g.. polystyrene or mineral wool.
In order to prevent the walls from soaking and soaking through their entire thickness, diaphragm walls are made with a non-partitioned gap of the width of 5-7 cm. Both walls are connected with wire or flat bar anchors placed vertically every 5-8 layers, and horizontally in steps of 1.0-1.5 m.