For a perfectly insulated building, the weakest points, such as the openings of the building, must be well insulated to eliminate thermal bridges. Once the end caps are in place on either side, the Lintel Closers need to be added into the block which will form the top of the door or window. The Lintel Closer should be trimmed so that it bears on the top of the End Caps on either side of the opening. This creates an unbroken thermal barrier between the concrete and the opening. Of course, it can also be used as the base of the window and in that case you are building an insulated home with passive building standards. The forms are available for 10cm (4 ”), 15cm (6”), 20cm (8 ”), 25cm (10”) and 30cm (12 ”) core and have an insulation thickness of 5cm.