Clasificación de los casos de uso

Masonry Basics Masonry types

Production and quarrying Properties

Common uses History Early uses of masonry

Technology developments Modern use

Masonry Construction Assembly methods Patterns

The arch and lintel Colors, Finishes, Textures Problem issues

The masonry trade

Introduction to masonry

Masonry is based on the need to build semi-permanent structures from durable individual units that can be stacked and adhered together. We consider masonry to be: clay brick, clay tile, concrete masonry units (CMUs), glass block, terra cotta, adobe, and stonework. Masonry construction has been found that is over 16,000 years old, and has been continually improved for durability, esthetics, and versatility.

Masonry is long lasting, weather resistant, and can provide building structure, cladding or both. Masonry is also fire resistant, provides thermal comfort, resists sound penetration, and can reduce overall sound levels. Systems may be designed as walls, columns, piers, pilasters, lintels, and arches, but always work most efficiently in compression. Masonry is used in virtually every type of build-ing application, and the colors and finishes of masonry are almost limitless.

Typical masonry construction is made up of small building units, which create maximum versatility of building form. Manufactured masonry units are made of clay, concrete, or glass and may be solid or hollow. Solid units have less than 25% open voids and are usually cored or have indentations that reduce weight and provide a better surface for mechanical bonding of the mortar.

Hollow masonry units are more than 25% open and the voids, or cells, are large enough to contain reinforcing bars and grout.

Manufactured clay masonry units are molded or extruded and then heated at over 870°C (1600°F). Adobe units are cured at low temperatures, sometimes by sun drying, and gain strength from emulsifiers or other binders. CMUs are molded from low water mixture concrete and gain strength through the chemical hydration of the cement.

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Mortar and grout are the bonding materials used to adhere masonry units together. Mortar is spread, or ‘buttered’, between units by the mason during stacking. Grout is poured or spread into cells and cavities in walls or between tiling units to fill gaps. Mortar and grout are made of a cement, aggregate, and water mixture similar to concrete – but with less aggregate and sometimes more water content to remain workable, spreadable, and pourable. Once the mortar or grout is placed between masonry units it sets quickly, due to the drying absorption of the porous masonry.

Masonry construction is often initially more expensive than other types of construction, but has an excellent life cycle cost. The construction is very durable, long lasting, is low maintenance, and is energy efficient. It also has a low environmental impact and is inert when downcycled as fill material.

Please note that while you may frequently see and hear the term ‘masonary,’

there is only one ‘a’ in the word.

Masonry basics

The most common type of masonry is the clay brick. Bricks are made in modular and non-modular sizes with specific nominal and actual dimensions (Fig. 3.2.1). The nominal dimensions in brick sizing are based on a completed assembly – meaning the final size in the wall with mortar joints included. The most common brick size is the ‘modular’ brick that is nominally 8 in. deep, 4 in. wide, and 2²⁄³in. high in the US, and 225
112.5
75 mm for the British Standard co-coordinating brick size. The height/width/depth dimensions are for common reference only, as units may be placed into the wall system in any orientation. The actual size of this unit is 7⁵⁄⁸in. deep, 3⁵⁄⁸in. wide, and 2¹⁄⁴in.

high, with a 3/8 in. mortar bed in the US and 215
102.5
65 mm (or 73 mm), with 10 mm mortar joints in the UK. This makes vertical coursing 8 in. high for every three rows of standard running bond in the US and 225 mm high for three rows in the UK, with 4–8 in. increments of wall length in the US and 112.5–225 mm increments in the UK. Working with these dimensions when designing is called ‘using brick module’ – understanding that height/open-ings/corners can only occur at increments of these dimensions. Other brick sizes and mortar bed thicknesses are possible and can be found in Figure 3.2.1. Keep in mind when using any material like brick, that labor costs far outweigh material costs – therefore using larger, more expensive individual units is cheaper overall due to the fact that fewer of them need to be placed to make a wall (this only works up to a reasonable size of unit, i.e., small enough for one person to easily carry). The rough dimensions of the basic modular brick have been in use for over 2500 years because of its size, it is easy to handle, and place with one hand for an entire work day.

Clay Tiles are far less commonly used since the large-scale production of CMUs became widespread. Clay tiles were largely used for structural appli-cations, as they were often larger open cell units that could be easily placed and grouted full if needed. They are also used as interior wall backup with brick veneers placed over top. CMU construction has taken the place of clay tiles in the US because the expense is less and the durability/strength of the

3.2 Materials: masonry

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concrete units are higher. Tiles are, however, still used in applications such as fireplace flues (where they are more heat resistant than concrete) and under-ground drainage systems (where they resist leakage better than concrete).

They are also used when the glazed tile look is desired or in situations where vandalism is a concern, because they can be cleaned of paint and stains easier than unglazed CMUs.

CMUs are molded from zero-slump concrete and cured with hot water ranging from 38°C (100°F) mist to 175°C (350°F) steam. This makes the units very strong and resistant to cracking and chipping. Most CMUs have hollow cores to reduce weight and allow for grout and reinforcing bars. The most common nominal size for a CMU in the US is 8 in. wide, 8 in. high and 16 in. long, the actual size being 7⁵⁄8
15⁵⁄8in., in the UK this is 24 cm wide, 23.8 cm high and 49.5 cm long. This makes each block row height the same as three ‘modular’

bricks and allows the two systems to be tied together easily in composite wall construction. Again, using the standard nominal block dimensions is referred to as designing in ‘block module’, and many times this module controls the overall

Unit Nominal dimensions (in.) Joint Actual dimensions (in.) Vertical

designation W H D thickness W H D coursing

Modular 4 2²⁄³ 8 ³⁄⁸ 3⁵⁄⁸ 2¹⁄⁴ 7⁵⁄⁸ 3C  in.

Unit Joint Actual dimensions (mm) Vertical

designation thickness W H D coursing

Standard coordinated 10 215 65 102.5 3C  210 mm

Imperial 10 215 73 102.5 3C  234 mm

Thin format 10 240 52 115 4C  238 mm

Standard format 10 240 71 115 3C  238 mm

1¹⁄²Standard format 10 240 113 115 2C  238 mm

3¹⁄²Standard format 10 240 113 175 2C  238 mm

Standard brick sizes and vertical coursing

USAUK

Note: UK Nominal and actual dimensions are equivalent. Check with masonry manufacturer to verify specifications.

Figure 3.2.1. Standard brick sizes and vertical coursing.

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dimensions of the building you’re designing (It’s much easier to know this from the start rather than making the mistake of having to go back and change all the dimensions on a set of drawings). CMUs come in so many shapes and sizes that it’s hard to call the most common 24
49.5 cm (8
16 in.) size standard (Fig.

3.2.2). The versatility and compressive strength of these units, paired with the fact that they are easily combined with steel reinforcing bars for tension cap-acity, make them nearly ubiquitous in most construction. They are resistant to corrosion, termites, winds, weather, and can be colored or textured easily.