The fixed frame forms the stationary base of every window or door unit and is installed flush into the wall opening. It transfers all occurring loads — self-weight, wind load, and operating forces — into the surrounding building structure. Anchoring is achieved using frame plugs, screws, or special mounting rails. A continuous joint between the fixed frame and the masonry is sealed with mounting foam, compressible tape, and sealing membranes according to installation guidelines to ensure airtightness and watertightness. The profile width of the fixed frame largely determines the structural properties and installation depth of the entire unit.