Division 04 Masonry describes the process of building with individual units of natural stone, or with man-made units such as brick or block. With examples of ancient masonry structures (some built more than 10,000 years ago) still in existence, masonry represents one of the oldest forms of construction. Masonry's demonstrated durability and relative ease of construction make it an ideal choice for buildings that are intended to last for ages.

Masonry can be laid up using a wide variety of units. However, the effort required to move large quantities of heavy materials over a long distance greatly influences the selection of masonry materials, limiting choices to the types of products that are available locally.

Developments in masonry construction, including improved mortar and the use of reinforcing, have resulted in stronger and lighter-weight structures that are also more durable.