All wreaths, both those on top of the walls under the walls, and rims of ceilings should be protected against heat loss by installing polystyrene or mineral wool insulation. From the outside, such insulation should be covered with a low wall made of ceramic bricks, best connected with a heat-insulating masonry mortar.. In many technologies, the insulation cover in the wreath is made of various types of hollow bricks, blocks or tiles with good thermal insulation, e.g.. Porotherm by Wienerberger.