In the recent years, together with the development of modern construction the tendency for opening housing spaces to gardens and terraces appeared. Traditionally applied single or double leaf balcony solutions appeared to be insufficient – sudden increase of the openings caused the increase of weight of a single leaf often exceeding the technical possibilities for such a window manufacturing. Additional difficulty in free moving was the application of a threshold in the types of windows. This is why modern terrace low-threshold systems were invented. Such solutions allowed for development of window openings even up to 19.8 m and application of the so-called low threshold enabled free movement for disabled people on wheelchairs and eliminated the hazard of tripping over by children playing around.
