The heat insulating plates are made from a material with closed pores with channels running cross the plane of the plate in the form of slits (2) with oblong preferably rectangular cross-section with the longer dimensions (1) running approximately horizontal. Adjoining slits open towards different sides of the plate. Slits arranged one above the other and separated from each other by horizontal partitions (4) open alternately towards the brickwork and to the outside of the building. Adjoining slits in one plane are separated from each other by vertical webs. The slits arranged in rows above each other are continuous over the largest part of the plate thickness and separated from each other by partitions having the same thickness over their surface extension.
