Masonry is the building of structures from individual units laid in and bound together by mortar. The common materials of masonry construction are brick, stone, concrete block, glass block, and tile. Masonry is a highly durable form of construction because the materials used are not much affected by the elements, but the quality of the mortar and the pattern the units are laid in can strongly affect the quality of the overall masonry construction.
Masonry is commonly used for the walls of buildings, foundations, and monuments. Brick masonry is the most common type of masonry, and may be either solid or veneered.
Brick veneer construction has strength imparted by a framework of wood or a rough masonry wall of other material over which is placed a layer of bricks for weatherproofing and providing a finished appearance. The brick veneer wall is connected to the structural walls by "brick ties", metal strips that are attached to the structural wall as well as the mortar joints of the brick veneer wall. There is typically an air gap between the brick veneer wall and the structural wall. As brick is not completely waterproof, the structural wall has a waterproof surface (usually tar paper) and weeping holes are left at the base of the brick veneer wall to ventilate the air gap. Veneered walls are often superior to solid brick walls because the core can be given characteristics different from that of the masonry exterior. For example, reinforced concrete or steel provides better structural support for buildings, and insulation or utility lines can be more easily included inside the wall.
Solid brick masonry is made of two or more layers of bricks with the bricks running longitudinally (called "stretcher" bricks) bound together with bricks running transverse to the wall (called "header" bricks). Each row of bricks is known as a "course." The pattern of headers and stretchers employed gives rise to different bonds such as the common bond (with every sixth course composed of headers), the English bond, and the Flemish bond (with alternating stretcher and header bricks present on every course). There are no significant utilitarian differences between most bonds, but the appearance of the finished wall is affected.
Blocks of cinder concrete ("cinder blocks" or "breezeblocks"), ordinary concrete ("concrete blocks"), or hollow tile are generically known as "building blocks." They are usually much larger than ordinary bricks and so are much faster to lay for a wall of a given size. Furthermore, cinder and tile blocks have much lower water absorption than brick masonry. They are often used as the structural core for veneered brick masonry, or are used alone for the walls of factories, garages, and other "industrial" buildings where appearance is not a significant factor.
Stone blocks used in masonry can be "dressed" or "rough." Stone masonry where the blocks are dressed to flat surfaces is known as ashlar masonry, whereas masonry using irregularly-shaped stones is known as rubble masonry. Both rubble and ashlar masonry can be laid in courses (rows of even height) through the careful selection or cutting of stones, but a great deal of stone masonry is uncoursed.
Masonry is strong in compression (vertical loads), but is relatively weak when subject to tension or sideways loads, unless reinforced. Walls are often strengthened against sideways loads by thickening the entire wall, or by building masonry piers (vertical columns or ribs) at intervals.
The strength of a masonry wall is not entirely dependent on the bond between the building material and the mortar; the friction between the interlocking blocks of masonry is often strong enough to provide a great deal of strength on its own. The blocks sometimes have grooves or other surface features added to enhance this interlocking, and some masonry structures forego mortar altogether. Stone masonry without the use of mortar was common in early civilizations.
A crinkle-crankle wall is a brick wall that follows a serpentine path, rather than a straight line. This type of wall is more resistant to toppling than a straight wall.
Other masonry related terms: Abated Wythe
Last updated: 05-07-2005 15:50:09
Last updated: 05-13-2005 07:56:04