Facts About Bricks and Brick Walls
Bricks have been around for thousands of years and are still an important part of the construction industry today. Modern bricks are made in much the same way as they were in the past. Clay is dug out of the earth, dried then crushed into a fine powder, and mixed with water to a specific consistency. The clay is then molded into units, dried in ovens, and finally baked in high-temperature kilns.
Bricks are named according to the clay they are manufactured from, the kind of method used in shaping the units (sand or water struck), how they are to be used (face brick or common), the strength, or the finish applied to the face after the initial firing such as glazed brick.
Common BrickCommon brick is made from surface clays and shale. There are few standards for color and texture but common brick is graded into three categories.
1. SW - Severe Weather; is for brick that is to be used for exterior construction in climates that combine wetness with temperatures below freezing.
2. MW – Moderate Weather; is for exterior use in dry climates that might possibly be subject to freezing temperatures.
3. NW – No Weather; is for interior use.
Face BrickFace brick is similar to common brick with the more attention given to color and texture. Residential and commercial buildings are typically constructed of face brick of one kind or another.
Fire brick is constructed of fire clay mined underground. This type of clay has an enormous resistance to heat, and fire brick is used exclusively in areas of high heat intensity, such as fireplaces and furnace liners.
Glazed BrickGlazed brick is fire brick coated with a ceramic glaze and then kiln-baked. The resulting brick might have a glossy or matte finish. A wide range of color possibilities is available in glazed brick.
Brick Styles and Sizes
See the table below for nominal and actual sizes for various bricks.
Split or Soap Brick
Queen Closer Brick
Brick Layout and Brick Walls
Along with the aesthetic considerations that are made when choosing a particular building unit is its texture and the method in which it will be bonded together into a wall. Most walls utilize a running bond which is what we normally picture when we think of a brick wall. There are many other layouts that have been used of the centuries.
Another important consideration is the type of mortar joint used to hold the bricks together. While many people think that the type of joint is only decorative, their shape also determines the way in which water is shed from the face of the wall. The type of brick can also determine the type of mortar joint to be used.
Mortar joints not only affect the appearance of the wall, but "striking" the joint helps bond the brick together and seal the wall against moisture. The Concave and V-shaped joints are extremely effective in resisting rain penetration. The Grapevine, Beaded and Weathered joints are also considered to be effective watertight joints. The Flush, Struck and Raked joints are difficult to make watertight. There are also other joints that are more decorative and should not be used on exterior applications such as weeping mortar joints.
Most mortar joints are raked to a depth of ¼ to ½ inch while the brick is being installed and then “tuck pointed” afterwards. This makes the initial wall installation go quickly and more care can be taken for the final appearance and performance of the wall.
Expansion or Control JointsA control joint is used to isolate one major building component with another. This is important for several reasons: 1) The control joint allows for the natural expansion and contraction of the brick which is necessary on very large sections; 2) The control joint allows for the brick to remain undamaged while the building settles; 3) Control joints are placed where walls intersect, such as inside corners to allow for independent movement, or where wall heights change.
Brick is very strong in compression, but weak in tension. Because it is an inelastic material and cannot resist bending stresses, brick cannot be used as a beam. It may, however, be made to span as an arch, where it is acting purely in compression.