The shapes and proportions of windows have a considerable influence on the architecture of a house. Besides the standard rectangular, arch head and segmental arched windows, symmetrical and asym-metric triangular, gabled or bay structures are available and house façades can be creatively shaped by means of a good distribution of window proportions.



The individual sashes of multi-sash windows have a large window surface, and can be fitted with dif-ferent types of brackets producing tilt, turn or tilt-and-turn windows. The window surface is divided by means of a fixed centre mullion or by means of a dummy sash. In this case, the centre mullion is fixed to one of the sashes, creating a complete, undivided window area when the sash is in the open posi-tion. For this reason, French windows provide a slimline solution in window construction. However, with wide windows, a fixed mullion should be provided on the sash overlap for safety reasons.