Bricks and Materials
Door and window openings in an external cavity wall require the cavity to be closed. The standard of thermal insulation that is now required will not allow the earlier method of closing with brick and a vertical d.p.c. as a cold bridge is formed. To overcome this an insulated plastic extrusion is fitted into the cavity, behind the frame, and is available in widths of 50mm; 75mm, and 100mm.