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:
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.
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.
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.
Massive precut stone is also known as "prefabricated", or "pre-sized" stone is a modern method of building with load-bearing stone. Precut stone is a DFMA construction method that uses large machine-cut stone blocks with precisely defined dimensions to rapidly assemble buildings in which stone is used as a major or the primary load-bearing material.
Massive precut stone construction was originally developed by Fernand Pouillon in the postwar period. He referred to the method as "pierre de taille" or "pré-taille" stone. It became possible through innovations by Pouillon and Paul Marcerou, a masonry engineer at a quarry in Fontvieille, to adapt high-precision saws from the timber industry to quarrying and stone sawing.
The key technique of massive precut (MP) stone is to cut stone ashlars to precise dimensions that match the architect's plan such that the stones can be dropped into place by crane for rapid construction. The blocks may be numbered so that the masons can follow the plan procedurally. The use of massive blocks reduces costs by minimizing sawing and fixer-masonry costs. The use of a crane reduces labor, accelerates construction, and allows the masons to precisely and quickly position the blocks.
MP stone is defined by four design attributes.
MP stone construction has advantages over conventional masonry and concrete construction.
Fernand Pouillon pioneered the use of massive precut stone in modern architecture. During the post-war period, his innovative approach to stone construction led to the development of numerous noteworthy projects, with a particular focus on housing. Throughout his long career, Pouillon played a crucial role in the development and popularization of massive precut stone construction techniques. His pioneering work laid the foundation for subsequent architects to build upon and innovate, leading to the resurgence and expansion of this construction method in the 2020s, with the rise of interest in low-carbon durable construction.
Post-tensioned stone (PT stone) is a high-performance composite construction material: 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.
Post-tensioned stone may consist of a single piece, but drill limitations and other considerations mean it is typically an assembly of multiple components with mortar between pieces. PT stone has been used in both vertical columns (posts), and in horizontal beams (lintels). It has also been used in more unusual engineering applications: arch stabilization, flexible foot bridges, and cantilevered sculptures.
Tensioned stone has a close affiliation with massive precut stone as two central techniques of modern stonemasonry.
"Post-tensioned stone increases the failure load of stone in bending, but also the stiffness of a structure by reducing joint cracking. This method of construction is widely used for concrete structures, but the advantages of using similar techniques with stone are only just being realised".
Stone has great compressive strength, so is ideal in compressive structures like stone arches. However, it has relatively weak flexural strength (compared to steel or wood), so in isolation cannot be safely used in wide spans under tension.
For concrete, this problem has been long solved: in addition to conventional tensile reinforcement, engineers developed prestressed concrete methods starting around 1888. Such tension-reinforced concrete applications combine compressive strength with pre-stressed tensile compression for combined strength much greater than either of the individual components, and have been in wide use for decades. As for concrete, post-tensioning maintains stone in compression, thereby increasing its strength.
Post-tensioning is achieved steel tendons either threaded through ducts within the stone elements or along their surface. Once the stone components are in place, the tendons are tensioned using hydraulic jacks, and the force is transferred to the stone through anchorages located at the ends of the tendons. The tensioning process imparts a compressive force to the stone, which improves its capacity to resist tensile stresses that could otherwise cause cracking or failure.
Stone is "natural precast concrete", so only needs to be cut (and strength tested) and post-tensioned prior to use in construction. Compared to concrete and steel, post-tensioned stone production has dramatically lower energy costs, with concomitant lower carbon emissions.
Stonemasonry is one of the earliest trades in civilization's history. During the time of the Neolithic Revolution and domestication of non-human animals, people learned how to use fire to create quicklime, plasters, and mortars. They used these to fashion homes for themselves with mud, straw or stone, and masonry was born.
The Ancients heavily relied on the stonemason to build the most impressive and long-lasting monuments to their civilizations. The Egyptians built their pyramids, the civilizations of Central America had their step pyramids, the Persians their palaces, the Greeks their temples, and the Romans their public works and wonders (See Roman Architecture). People of the Indus Valley Civilization, such as at Dholavira made entire cities characterized by stone architecture. Among the famous ancient stonemasons is Sophroniscus, the father of Socrates, who was a stone-cutter.
Castle building was an entire industry for the medieval stonemasons. When the Western Roman Empire fell, building in dressed stone decreased in much of Western Europe, and there was a resulting increase in timber-based construction. Stonework experienced a resurgence in the 9th and 10th centuries in Europe, and by the 12th-century religious fervour resulted in the construction of thousands of impressive churches and cathedrals in stone across Western Europe.
Medieval stonemasons' skills were in high demand, and members of the guild, gave rise to three classes of stonemasons: apprentices, journeymen, and master masons. Apprentices were indentured to their masters as the price for their training, journeymen were qualified craftsmen who were paid by the day, and master masons were considered freemen who could travel as they wished to work on the projects of the patrons and could operate as self-employed craftsmen and train apprentices. During the Renaissance, the stonemason's guild admitted members who were not stonemasons, and eventually evolved into the Society of Freemasonry; fraternal groups which observe the traditional culture of stonemasons but are not typically involved in modern construction projects.
A medieval stonemason would often carve a personal symbol onto their block to differentiate their work from that of other stonemasons. This also provided a simple "quality assurance" system.
The Renaissance saw stonemasonry return to the prominence and sophistication of the Classical age. The rise of the humanist philosophy gave people the ambition to create marvelous works of art. The centre stage for the Renaissance would prove to be Italy, where Italian city-states such as Florence erected great structures, including the Florence Cathedral, the Fountain of Neptune, and the Laurentian Library, which was planned and built by Michelangelo Buonarroti, a famous sculptor of the Renaissance.
When Europeans settled the Americas, they brought the stonemasonry techniques of their respective homelands with them. Settlers used what materials were available, and in some areas, stone was the material of choice. In the first waves, building mimicked that of Europe, to eventually be replaced by unique architecture later on.
In the 20th century, stonemasonry saw its most radical changes in the way the work is accomplished. Prior to the first half of the century, most heavy work was executed by draft animals or human muscle power. With the arrival of the internal combustion engine, many of these hard aspects of the trade have been made simpler and easier. Cranes and forklifts have made moving and laying heavy stones relatively easy for the stonemasons. Motor powered mortar mixers have saved much in time and energy as well. Compressed-air powered tools have made working of stone less time-intensive. Petrol and electric-powered abrasive saws can cut through stone much faster and with more precision than chiseling alone. Cemented carbide-tipped chisels can stand up to much more abuse than the steel and iron chisels made by blacksmiths of old.
Stonemasons use a wide variety of tools to handle and shape stone blocks (ashlar) and slabs into finished articles. The basic tools for shaping the stone are a mallet, chisels, and a metal straight edge. With these one can make a flat surface – the basis of all stonemasonry.
Chisels come in a variety of sizes and shapes, dependent upon the function for which they are being used and have many different names depending on locality. There are different chisels for different materials and sizes of material being worked, for removing large amounts of material and for putting a fine finish on the stone. A drove chisel is used for smoothing off roughly finished stones.
Mixing mortar is normally done today with mortar mixers which usually use a rotating drum or rotating paddles to mix the mortar.
The masonry trowel is used for the application of the mortar between and around the stones as they are set into place. Filling in the gaps (joints) with mortar is referred to as pointing. Pointing in smaller joints can be accomplished using tuck pointers, pointing trowels, and margin trowels, among other tools.
A mason's hammer has a long thin head and is called a Punch Hammer. It would be used with a chisel or splitter for a variety of purposes
A walling hammer (catchy hammer) can be used in place of a hammer and chisel or pincher to produce rubble or pinnings or snecks.
Stonemasons use a lewis together with a crane or block and tackle to hoist building stones into place.
Today power tools such as compressed-air chisels, abrasive spinners, and angle grinders are much used: these save time and money, but are hazardous and require just as much skill as the hand tools that they augment. But many of the basic tools of stonemasonry have remained virtually the same throughout vast amounts of time, even thousands of years, for instance when comparing chisels that can be bought today with chisels found at the pyramids of Giza the common sizes and shapes are virtually unchanged.
Traditionally medieval stonemasons served a seven-year apprenticeship. A similar system still operates today.
A modern apprenticeship lasts three years. This combines on-site learning through personal experience, the experience of the tradesmen, and college work where apprentices are given an overall experience of the building, hewing and theory work involved in masonry. In some areas, colleges offer courses which teach not only the manual skills but also related fields such as drafting and blueprint reading or construction conservation. Electronic Stonemasonry training resources enhance traditional delivery techniques. Hands-on workshops are a good way to learn about stonemasonry also. Those wishing to become stonemasons should have little problem working at heights, possess reasonable hand-eye coordination, be moderately physically fit, and have basic mathematical ability. Most of these things can be developed while learning.
The modern stonemason undergoes comprehensive training, both in the classroom and in the working environment. Hands-on skill is complemented by an intimate knowledge of each stone type, its application, and best uses, and how to work and fix each stone in place. The mason may be skilled and competent to carry out one or all of the various branches of stonemasonry. In some areas, the trend is towards specialization, in other areas towards adaptability.
Today's stonemasons undergo training that is quite comprehensive and is done both in the work environment and in the classroom. It isn't enough to have hands-on skills only. One must also have knowledge of the types of stones as well as its best uses and how to work it as well as how to fix it in place.
Stonemasons use all types of natural stone: igneous, metamorphic and sedimentary; while some also use artificial stone as well.
Many of the world's most famous buildings have been built of sedimentary stone, from Durham Cathedral to St Peter's in Rome. There are two main types of sedimentary stone used in masonry work, limestones and sandstones. Examples of limestones include Bath and Portland stone. Yorkstone and Sydney sandstone are the most commonly used sandstone.
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