Bricks composed of natural clay added with natural additives are called hollow clay bricks. These are lightweight and efficient since these are hollow from the inside. The bricks bond well with plaster and keep a good moisture balance in the building. Buildings with hollow clay brick walls are quiet thanks to their good sound insulation. Among the benefits you can get are reduced dead loads, quick construction and lower construction costs. The waterproof clay bricks can have different compressive strength, water absorption rate, density and thermal conductivity.