thumb|A mason laying a [[brick on top of the mortar]]

thumb|Bridge over the [[Isábena (river)|Isábena river in the Monastery of Santa María de Obarra, masonry construction with stones]]

Masonry is the craft of building a structure with stone, brick, concrete, or similar material, including mortar plastering, which are often laid in, bound, and pasted together by mortar. The term masonry can also refer to the building units (stones, bricks, concrete blocks, etc.) themselves.

The common materials of masonry construction are bricks and building stone; rocks such as granite, marble, and limestone; cast stone, concrete blocks, glass blocks, and adobe. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which the units are assembled can substantially affect the durability of the overall masonry construction.

A person who constructs masonry is called a mason or bricklayer, or in some places colloquially a "brickie". These are both classified as construction trades.

History

Masonry is one of the oldest building crafts, even predating written history. The construction of Egyptian pyramids, Roman aqueducts, and medieval cathedrals are all examples of masonry. Early structures used the weight of the masonry itself to stabilize the structure against lateral movements. The types and techniques of masonry used evolved with architectural needs and cultural norms. Since mid-20th century, masonry has often featured steel-reinforced elements to help carry the tension force present in modern thin, light, tall building systems.

Applications

Masonry has both structural and non-structural applications. Structural applications include walls, columns, beams, foundations, load-bearing arches, and others. On the other hand, masonry is also used in non-structural applications such as fireplaces, chimneys and veneer systems.

Disadvantages

  • Extreme weather, under certain circumstances, can cause degradation of masonry due to expansion and contraction forces associated with freeze-thaw cycles.
  • Masonry tends to be heavy and must be built on a stable ground made of either undisturbed or mechanically-compacted soil, otherwise cracking may occur.
  • Unlike concrete, masonry construction does not lend itself well to mechanization, and requires more skilled labor. CMUs can be manufactured to provide a variety of surface appearances. They can be colored during manufacturing or stained or painted after installation. They can be split as part of the manufacturing process, giving the blocks a rough face replicating the appearance of natural stone, such as brownstone. CMUs may also be scored, ribbed, sandblasted, polished, striated (raked or brushed), include decorative aggregates, be allowed to slump in a controlled fashion during curing, or include several of these techniques in their manufacture to provide a decorative appearance.

"Glazed concrete masonry units are manufactured by bonding a permanent colored facing (typically composed of polyester resins, silica sand and various other chemicals) to a concrete masonry unit, providing a smooth impervious surface."

Glass block

Glass block or glass brick are blocks made from glass and provide a translucent to clear vision through the block.

Veneer masonry

A masonry veneer wall consists of masonry units, usually clay-based bricks, installed on one or both sides of a structurally independent wall usually constructed of wood or masonry. In this context, the brick masonry is primarily decorative, not structural. The brick veneer is generally connected to the structural wall by brick ties (metal strips that are attached to the structural wall, as well as the mortar joints of the brick veneer). There is typically an air gap between the brick veneer and the structural wall. As clay-based brick is usually not completely waterproof, the structural wall will often have a water-resistant surface (usually tar paper) and weep holes can be left at the base of the brick veneer to drain moisture that accumulates inside the air gap. Concrete blocks, real and cultured stones, and veneer adobe are sometimes used in a very similar veneer fashion.

Most insulated buildings that use concrete block, brick, adobe, stone, veneers or some combination thereof feature interior insulation in the form of fiberglass batts between wooden wall studs or in the form of rigid insulation boards covered with plaster or drywall. In most climates this insulation is much more effective on the exterior of the wall, allowing the building interior to take advantage of the aforementioned thermal mass of the masonry. This technique does, however, require some sort of weather-resistant exterior surface over the insulation and, consequently, is generally more expensive.

Gabions

thumb|Gabion Wall

Gabions are baskets, usually now of zinc-protected steel (galvanized steel) that are filled with fractured stone of medium size. These will act as a single unit and are stacked with setbacks to form a revetment or retaining wall. They have the advantage of being well drained, flexible, and resistant to flood, water flow from above, frost damage, and soil flow. Their expected useful life is only as long as the wire they are composed of and if used in severe climates (such as shore-side in a salt water environment) must be made of appropriate corrosion-resistant wire. Most modern gabions are rectangular. Earlier gabions were often cylindrical wicker baskets, open at both ends, used usually for temporary, often military, construction.

Similar work can be done with finer aggregates using cellular confinement.

Passive fire protection (PFP)

Masonry walls have an endothermic effect of its hydrates, as in chemically bound water, unbound moisture from the concrete block, and the poured concrete if the hollow cores inside the blocks are filled. Masonry can withstand temperatures up to and it can withstand direct exposure to fire for up to 4 hours. In addition to that, concrete masonry keeps fires contained to their room of origin 93% of the time. For those reasons, concrete and masonry units hold the highest flame spread index classification, Class A.

Fire cuts can be used to increase safety and reduce fire damage to masonry buildings.

Mechanical modeling of masonry structures

thumb|A comparison (using transmission [[photoelasticity) between the stress diffusion in an elastic body (on the left) and a model of masonry (on the right). A highly localized stress percolation is visible on the right.]]

From the point of view of material modeling, masonry is a special material of extreme mechanical properties (with a very high ratio between strength in compression and in tension), so that the applied loads do not diffuse as they do in elastic bodies, but tend to percolate along lines of high stiffness.

See also

References

General references

  • Mason Contractors Association of America
  • International Masonry Institute
  • National Concrete Masonry Association
  • Masonry Institute of America
  • Illustrated Glossary of Stone Industry Terms