Three-layer assembly in JWS SYSTEM (JARO-MAX WINDOW SYSTEM) is the solution preventing from the formulation of thermal bridges in the area of window or door joinery and wall connection. This is the place, where the construction is being degraded in the quickest way. In the event of traditional assembly, foam looses own thermal and acoustic properties due to humidity and altering temperatures. Subsequent problems are as follows: peeling of paint, frosting at walls, humidity, fungal attack and excessive heat consumption.