Most glazed bricks and glazed clay tiles are fired twice – the first firing concerns the ceramic body, and in the second firing the glaze is applied to the brick surface. Double firing of glazed bricks means a 100% increase in energy costs that must be used for the second firing when the body is covered with the applied glaze. Glazed ceramic bricks are not only a product that wastes energy during its production. Double firing of this type of brick and tiles makes the glazed surface very resistant to destructive conditions – such as salts, acids, snow mud. Double-fired glazed bricks can be built in places where ordinary ceramic bricks cannot withstand.
