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Class Day Twelve. Chapter 8 Brick Masonry. History of Brick Masonry. A No one really knows the age of brick masonry.
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Chapter 8 Brick Masonry
History of Brick Masonry • A No one really knows the age of brick masonry. • B Common sense would dictate that the lack of construction materials for shelter in lands where no natural stone was available, would lead to innovations with whatever material is at hand • C Where there was land there was soil, and if there was water there was mud. And soil particles stick together and form a hard mass when the sun dries the moisture. • D Mud bricks were molded by hand and allowed to dry in the sun, and stockpiled for future use. Small units were easily handled.
E Mud bricks were stacked with mud mortar, which varied in thickness to accommodate irregular shapes. • F It was learned that the best bricks were made of soil that had very tiny particles and became sticky when wet. The material we call clay. • G In the southwest regions of North America, “Adobe” bricks were made of a clay that has come to be known as adobe clay, which was particularly good for making mud bricks. Adobe was further strengthened by adding short strands of straw to the mix. Adobe bricks are still made and used today.
H Consistency of size did not become prevalent until units were cast into molds, which greatly facilitated ease of assembly. • I The industrial revolution of the late 1800s brought about the firing of masonry in kilns, which made the units very hard and strong. • J In the early 1900s other materials surpassed brick in use because of strength requirements for buildings too tall and heavy to be supported by a “mass” type wall. • K But brick has and intimacy about it that remains a warm and friendly material for use in construction of residences and office buildings
BRICK MORTAR • A Mortar is a vital part of brick construction. • B As bricks are made of clay, then fired in a furnace to remove the moisture and make them hard, they are impossible to make in exact, consistent size – but in modern day it is close. • C In early times, mortar was used as a cushion to align the assembly process to maintain square and plumb in a structure. Additional strength in the mortar mix was not necessary because it was made of the same material as brick. • D But since fired bricks are much stronger than the original sun-dried clay, the strength of mortar was improved to make stronger buildings.
E With the development of natural cement for the manufacture of concrete, it became a natural matrix for masonry mortar. • F Mortar is a mix much like concrete; which consists of stone aggregates held together by a matrix. In the case of concrete, that consists of a gradation of large rocks, smaller rocks, and still smaller particles (sand) – all mixed consistently and held together by a paste of cement and water, which hardens by a chemical process called hydration. • G Masonry mortar is a mixture of sand, cement, and water, with the addition of lime to lend smoothness and workability to the mix.
Mortar Functions • Provides for full bearing of weight • Maintains the strength of the masonry wall • Seals against moisture and vermin • Bonds the masonry units together • It should be a part of the aesthetic value of a building.
MAKING BRICKS • A Early molding of bricks was done by shaping a mass of mud by hand. • B Then individual single molds made of wood increased production and consistency of size. • C Then multiple molds made of wood increased production even more. • D Today, very sophisticated methods exist for shaping bricks by extruding clay through a steel form, then cutting to individual units with wire.
E The making of bricks became more sophisticated with units extruded and wire cut, then fired in gas kilns. Production and quality of units increased tremendously. • F The color of bricks up until approximately 20 years ago depended upon the color of clay, which was found in large deposits in the ground. • G Constant use of brick as a veneer in residential and commercial construction as population grew, led to depletion of consistent color clay deposits. • H Now, nearly all brick used in residential construction are made of any clay, but given their color by a slurry mix that is applied to the units before firing.
Basic types of brick: • Common brick: Units made of clay where color and surface finish are not a factor, because of use as a “backup” structural material in an area where it will never be seen. • Face brick: Units made where appearance is the main consideration. Face brick for commercial use is still made with specific colors of clay. • Special bricks may be made for specific purposes. Should an Architect desire a special shape to be used in creating an unusual desired effect in a design, brick companies will custom make the units.
Fire brick is made of a specific type of white clay, with special additives for use in the firebox of fireplaces, ovens, kilns, and other firing mechanisms. • Bricks, generally are made with holes (except fire brick) to reduce the weight of material not needed for structure, and to provide a method for additional adherence of mortar. • Bricks made of the same material as concrete masonry units are available on a limited basis, but have never been accepted for widespread use.
BRICK SHAPES AND SIZES • The text shows a chart with 12 sizes of bricks, but all available sizes and shapes are not listed. • Two shapes of brick are commonly used, but many others are made for specific purpose. • Modular Brick – nominally lay 8” long, 4” thick, & 3 courses high = 8”. Texas Tech uses modular brick. For use where strength and appearance is important. • King Size Brick – nominally lay 10” long, 3” thick, & 2 ½” high. For use as a veneer where economy is the main concern.
Eight modular size bricks are required to lay one square foot of surface wall, but it takes only 5.4 king size bricks for the same area. So, king size brick are made strictly for economy. • Bricks shapes made for appearance: • Roman brick – basically 12” long, 4” thick, 1 ½” high. • Norman brick – basically 12” long, 4” thick, 3 courses = 8” high. • Big Johns – basically 12” long, 4” thick, 4” high.
BRICK ARRANGEMENT TERMINOLOGY • A Bricks are laid in a variety of arrangements, mostly today for the sake of appearance. In earlier times when a wall consisted of several layers thickness, bricks were turned endways through the wall for structural bond. Named patterns evolved in the process, such as English bond, Flemish bond, etc. • B Common course pattern for structure and appearance: • Stretcher – Bricks laid flat end to end. • Soldier – Laid vertically so the outside long edge shows. • Rowlock - Laid so the end shows, vertically. • Header – Laid so the end shows, horizontally
Basic Brickwork Terminology Head Joint Bed Joint Course - horizontal layer of brick
Brickwork Terminology Header - Bonds two wythes together Wythe: vertical layer 1 unit thick Rowlock - laid on face, end visible Stretcher - long dimension horizontal & face parallel to the wall Soldier - Laid on its end, face parallel
Brick Masonry - Sizes and Shapes • There is No standard size • Normal coursing - 3 modular bricks = 8” • Larger sizes available • Custom shapes & colors are available
Masonry Joints Weathered • Various tools are used to treat the surface finish of mortar joints. • Some are done to repel water, but most are done for appearance. Concave Vee Flush Raked Stripped Struck
In the category of the Earnheardts, Emmet Smith, Tiger Woods, etc, this man is the world champion bricklayer of 2004. In a contest in Las Vegas, Bob Bol laid 765 bricks in ONE HOUR. That’s 12.75 bricks per minute – or one brick every 5 seconds. • He won a prize of $2,000.
