MASONRY AND BUILDING. Masonry, from the French, maconnerie, meaning stone or brick work, derived from the Latin, maceria, a wall, is the operation of laying up natural or artificial stones, generally held together or made a single mass by mortar, plaster or earth. It is the most important part of stone and brick structures, and a mason frequently becomes the general contractor for a whole building of this class. The different trades required in mason building begin with building movers or the workmen who raze or demolish old build ings; then come the excavating, dr inage, grad ing, paving, piling, foundations, rubble, cut stone, including cut moldings, modeling and stonecarving, brick masonry, concrete work, fireproofing, terra-cotta work. After this heavier construction follows lighter mason work: plastering on metal or wood lathing, and stucco. The ideal of good masonry is a struc ture of natural or artificial stone that shall stand as the permanent skeleton of the building, firm and enduring; its great first cost shall mean no further care or expense.
History,— The Egyptian stonework that has survived the centuries is generally of enormous blocks jointed with astonishing accuracy, so as not to mar the effect of the bas-reliefs which covered several courses. Assyrian walls were laid up with bricks forming the exterior surface and the interior was filled with rubble and earth. The Opus reticulatum and opus incertum were later Roman forms where small blocks of tufa or triangular brick were used for the exterior surface and the interior was filled with concrete. The characteristic of Greek masonry was to use local stone, accurately cut and jointed if the stone would bear it; otherwise covered with stucco. From the lintel or beam architecture of the Greeks to the arch construction of the Romans was an advance in the possibility of size of construction, but from a system of making the constructive forms visible and decorative to a custom of covering rough walls with a decorative shell not expressing the sup porting masonry work behind. This method of building gave the Romans an opportunity to make their enormous structures at a low cost, because unskilled labor could be employed to much better advantage, needing only a small number of foremen. Romanesque masonry was very crude and the thrusts of the arches were taken care of by a mass of abutments which were practically monolithic. In Byzantine work the arches and domes were made from small blocks of stone and the thrusts were studied with much greater care. In Gothic
work the arch became °alive,” carrying the weights and thrusts of the upper parts of the building on slender shafts, and through flying buttresses with the utmost skill to the outer walls and buttresses. Modern work has come to partake of the character of the ancient Roman that is, a veneer on interior supporting masonry of a different character. In our time, however, instead of the huge con crete monolithic buildings, an iron skeleton is used, and a thin shell often not more than four inches in thickness covers a frame work of steel beams that in a high building is little more than an iron bridge on end. The old Roman flat arch construction of thin bricks or tiles held together by strong cement forming domes not over six inches thick and easily spanning 15 feet or 20 feet is also used.
Men and The workmen em ployed on masonry are stonecutters, who gen erally work in stone yards away from the build ing, except for such trimming as may be neces sary in setting the stone; stonemasons who work on the building, setting the stone; brick layers who work on platforms continually raising and placing the brick accurately; and laborers for delivering the stone, mortar, etc., and for mixing mortar and concrete. The ma terials used are stone, cement blocks, brick, terra-cotta, broken stone, cinders; and adhesive materials: limes and cements, which are used with sand to make a mortar for binding the materials together. In very crude construction, mud and clay are used for a binding material. Foundation walls may he of stone laid dry; of concrete; of stone laid in Portland cement mortar or half-cement mortar, the latter con sisting of sand, cement, lime, with cement and lime in equal proportions. In case of the soil under the building not being sufficiently firm, it is necessary either to drive wooden piles or to spread the foundation so far that the pressure per square foot on the soil will not be sufficient to cause the building to settle. In Chicago the footings are very large, of steel beams and concrete, making what is prac tically a raft so that the building really floats on a soft soil. Where the foundations are under water, as under a bridge pier, it i necessary to adopt special methods, generally sinking cais sons so that workmen may go down and work under water.