Stonemasonry


Stonemasonry or stonecraft is the creation of buildings, structures, and sculpture using stone as the primary material. Stonemasonry is the craft of shaping and arranging stones, often together with mortar and even the ancient lime mortar, to wall or cover formed structures.
The basic tools, methods and skills of the banker mason have existed as a trade for thousands of years. It is one of the oldest activities and professions in human history. Many of the long-lasting, ancient shelters, temples, monuments, artifacts, fortifications, roads, bridges, and entire cities were built of stone. Famous works of stonemasonry include Göbekli Tepe, the Egyptian pyramids, the Taj Mahal, Cusco's Incan Wall, Taqwesan, Easter Island's statues, Angkor Wat, Borobudur, Tihuanaco, Tenochtitlan, Persepolis, the Parthenon, Stonehenge, the Great Wall of China, the Mesoamerican pyramids, Chartres Cathedral, and the Stari Most.
While stone was important traditionally, it fell out of use in the modern era, in favor of brick and steel-reinforced concrete. This is despite the advantages of stone over concrete. Those advantages include:
  • Many types of stone are stronger than concrete in compression.
  • Stone uses much less energy to produce, and hence its production emits less carbon dioxide than either brick or concrete.
  • Stone is widely considered aesthetically pleasing, while concrete is often painted or clad.
Modern stonemasonry is in the process of reinventing itself for automation, modern load-bearing stone construction, innovative reinforcement techniques, and integration with other sustainable materials, like engineered wood.

Stonemasonry disciplines

  • A quarryman splits or cuts rock in the quarry, and extracts the resulting blocks of stone. The cut or split pieces are collected and transported away from the extraction surface for further refinement.
  • A sawyer stonemason cuts these stone blocks into dimension stone, to required size with saws. The resulting block, if ordered for a specific component, is known as sawn six sides. A sawyer mason is similar to a banker mason in that they work with rough pieces of stone and shape them according to certain standards. The main difference between a sawyer mason and a banker mason is the size of the stone they work with. A sawyer mason typically works with much larger pieces and uses diamond-coated tools. Sawyer masons may work in quarries or be found in tile or flooring stores, possessing a range of specific skills, such as examining grain patterns to determine cleavage, creating smaller stones from larger pieces, and carving precise outlines and drilling holes using various tools like chisels.
  • A banker mason, sometimes referred to as a bank mason, is workshop-based, and specializes in working the stones into the shapes required by a building's design, this set out on templets and a bed mould. A banker mason uses various hand and power tools to cut, carve, and shape stone. They can produce anything from stones with simple chamfers to tracery windows, detailed mouldings and the more classical architectural building masonry. When working a stone from a sawn block, the mason ensures that the stone is bedded in the right way, so the finished work sits in the building in the same orientation as it was formed on the ground. Occasionally though some stones need to be oriented correctly for the application; this includes voussoirs, jambs, copings, and cornices. The stone's size and shape are usually predetermined by builders or other parties involved in a project, and the banker mason works according to a brief or a set of designs provided for that project. Once the stone has been crafted to the required specifications, it is transported to the construction site or another location for use in a building or other structure.
  • A fixer mason specializes in the fixing of stones onto buildings, using lifting tackle, and traditional lime mortars and grouts. Sometimes modern cements, mastics, and epoxy resins are used, usually on specialist applications such as stone cladding. Metal fixings, from simple dowels and cramps to specialized single application fixings, are also used. The precise tolerances necessarily make this a highly skilled job. A fixer mason is responsible for traveling to a job site to fit and lay pre-prepared stone or cladding for buildings. They might do this with grouts, mortars, and lifting tackle. They might also use things like single application specialized fixings, simple cramps, and dowels as well as stone cladding with things like epoxy resins, mastics, and modern cements.
  • A memorial mason or monumental mason carves gravestones and inscriptions.
  • A carver mason crosses the line from craft to art. They use their artistic ability to carve stone into foliage, figures, animals or abstract designs. Carver masons are the artists of stonemasonry, responsible for creating designs and/or patterns from stone, as well as on stones. This work can include stone sculptures of figures or animals, or other projects of a similar nature. Throughout history, carver masons have been renowned for their exceptional skills in crafting beautiful pieces from stone.

    Classical stonemasonry techniques

Stone has been used in construction for thousands of years, in many contexts. Listed below are six types of classical stonemasonry techniques, some of which still see widespread use.
  • Ashlar masonry. Stone masonry using dressed stones is known as ashlar masonry.
  • Trabeated systems. One of the oldest forms of stone construction uses a lintel laid across stone posts or columns. This method predates Stonehenge, and refined versions were used by the Egyptians, Persians, Greeks, and Romans.
  • Arch masonry. Also called "arcuated systems" in contrast with trabeated systems, which are two ancient methods for creating a void below a stone span. Note that the Wikipedia page on stone arches is about stone-arch bridges exclusively, and the arch page is about all arches, including non-stone.
  • Rubble masonry. Use of rubble in masonry: antonymous to ashlar masonry. Can be infill in an ashlar wall, used in cyclopean concrete, and other contexts. The term is antonymous to "ashlar".
  • Dry stone. Stone walls built without mortar, using the shape of the stones, compression, and friction for stability. This technique encompasses cyclopean masonry and other mortar-less methods, but is conventionally used to describe agricultural walls used to mark boundaries, contain livestock, and retain soil.
  • Cyclopean masonry. Drywall construction using massive boulders that may have been shaped to fit together. Polygonal masonry is a subtype of cyclopean masonry where the boulders are shaped into polygonal profiles.

    Modern stonemasonry systems

In the modern era, stone has been largely relegated to being a cosmetic element of buildings, often used as decorative cladding on steel-reinforced concrete. This is despite its wide historical use in large compressive structures: 50-m bridges and colosseums in Roman times, ~65-m tall cathedrals since the Middle Ages, and 12-story apartment buildings built in the 1690s.

Modern stonemasonry techniques

  • Stone veneer is used as a protective and decorative covering for interior or exterior walls and surfaces. The veneer is typically 1 in thick and must weigh less than 15 lb per square foot so that no additional structural supports are required. The structural wall is put up first, and thin, flat stones are mortared onto the face of the wall. Metal tabs in the structural wall are mortared between the stones to tie everything together, to prevent the stonework from separating from the wall.
  • Massive precut stone. Also known as "prefabricated stone", "massive stone", "pre-sized stone", or "pré-taille" stone.
  • Post-tensioned stone. A high-performance composite construction material consisting of stone held in compression with tension elements. The tension elements can be connected to the outside of the stone, but more typically uses tendons threaded internally through a duct formed from aligned drilled holes.
  • Pre-tensioned stone. Using an epoxy shear connector, early experiments have shown that it is possible to pre-tension stone, maintaining the tendon under tension while the liquid epoxy is injected and allowed to set.
  • Digital stereotomy. Using CAD and computer models of load, modern designers are able to cut complex vaults, arches, and other arrangements of precisely cut ashlars. Antecedents to this discipline include curved vaults, and also flat vaults that use a concentric flat arch vault and the Abeille flat vault. Using digital design and machining, such compression structures can be shapes into complex compressive structures. Leaders in this area include Giuseppe Fallacara and Philippe Block.
  • Trabeated stone exoskeleton. In the modern era, post-and-lintel construction was adapted use as a stone exoskeleton in the design of 15 Clerkenwell Close. The stone exoskeleton method is a variant of the massive precut stone method: the ends of the posts and lintels are precisely precut offsite prior to assembly by crane. At least two more trabeated stone exoskeleton high-rise buildings are underway, one in London, and another in Bristol.
  • Stone bricks. Small stone ashlars that are cut by the quarry to brick sizing to allow their use in standardized brick-laying workflows. Cost is similar to clay composite bricks, but with greatly reduced carbon emissions. As stone does not change size like fired clay bricks, brick-sized stone ashlars do not require expansion joints.
  • Cyclopean concrete. This method uses a combination of cyclopean masonry and rubble masonry: boulders and or rubble are placed in a form, and concrete is poured on top to bind the stones together before removing the form. Variations of this include Frank Lloyd Wright's 'desert masonry' and Institut Balear de l'Habitatge's cyclopean concrete blocks, which are cast in a large slab and precisely sawn for use as prefabricated masonry in the massive precut stone system.
  • Slipform stonemasonry is a variation of Cyclopean concrete stone-wall construction that uses formwork to contain the rocks and mortar while keeping the walls straight. Short forms, up to two feet tall, are placed on both sides of the wall to serve as a guide for the stonework. Stones are placed inside the forms with the good faces against the formwork. Concrete is poured behind the rocks. Rebar is added for strength, to make a wall that is approximately half reinforced concrete and half stonework. The wall can be faced with stone on one side or both sides.
  • Formwork stone. "Pierre banchée" in French. Uses stone tiles or ashlars as shuttering for pouring concrete. These are left in place after the concrete sets. This is the inverse procedure to stone cladding, where the stone tiles are attached to the concrete after the temporary shuttering has been removed. Developed by Fernand Pouillon to accelerate construction. Formwork stone is distinct from cyclopean concrete in that the former uses rectilinear tiles, while the latter uses boulders and/or cobblestone.