Masonry refers to building – stone, brick, concrete block, tile, terra cotta, or stucco – materials that are used to construct and ornament building walls and architectural elements, such as chimneys, parapets, and steps. As construction material, masonry consists of individual units of brick, block, or stone and mortar as a bonding material. Mortar primarily plays a structural role, but also contributes to the visual character of the building.
Retain original masonry and mortar whenever possible without the application of any surface treatment. Concealing original masonry is not recommended.
Clean masonry only when necessary to halt deterioration or remove heavy soiling. Use the gentlest means possible to prevent damage to masonry surfaces.
Apply paint only to areas that have been previously painted.
Where there is evidence of deterioration, duplicate old mortar in strength, composition, color and texture. Replace old mortar joints in width and in joint profile.
Masonry is a highly durable building material, but it is particularly vulnerable to inappropriate cleaning and repair. Proper assessment of underlying problems, particularly those related to water damage, is critical before deciding on repair and treatment.
Sandblasting brick or stone surfaces using dry or wet grit or other abrasives is strongly discouraged as it will mar, damage, and weaken the masonry. High pressure water and cleaning methods should also be avoided since they can damage and weaken the masonry.
When necessary, replace masonry features of brick, stone, terra cotta, and/or concrete using the same materials, or one that is a compatible substitute material, matching the original in size, color, texture, density and profile.