Abstract: This invention relates to high-temperature kilns such as those used for bng ceramic products. It relates more particularly to the design and construction of the roof of such kilns. According to this invention, the roof (1) is flat and is composed of bricks (4) placed side-by-side which are permanently pressed together by resilient means (16) resting against a rigid external structure (12). The roof bricks (4) are provided with narrow notches (5-9). The combined effect of these notches with the lateral thrust from the springs (16) gives rise within the roof (1) to an arcuate orientation of prestressing forces, so that the flat roof (1) offers a mechanical resistance which matches the resistance of an arched vault, without having the drawbacks of a conventional arched structure, in which the inner volume of the arch is practically useless and causes an uneven heat distribution.