MEASUREMENT AND COST Methods of Measurement.—In engineering work it is usual to estimate stone masonry in cubic yards of actual masonry. When parts of the work are of special character, requiring cut-stone finish, special prices per cubic yard may be given, or the additional costs of the cut surfaces are paid for by the square yard.
In architectural work masonry is measured by the cubic yard or by the perch. A perch may be 161, 22, or 25 cubic feet, accord ing to the custom of the locality in which the masonry is constructed. In the use of the perch as a unit, it is advisable to state the number of cubic feet to be considered a perch.
In building work it is common to take outside measurements of walls, thus including the corner masonry twice; it is also custom ary to measure small openings as solid wall. Commonly openings less than 70 square feet are not deducted. In some cases allow ances are made for openings more than 6 feet wide. Customs differ in different parts of the country, and it is necessary to know the local usage, unless the method of measurement is stated.
55. Cost of Stone Masonry.—So many items are included in the cost of masonry and these items vary so widely in different localities that it is not feasible to give any definite values to the costs of different kinds of work. The items of cost include the price of the rough stone at the quarry, the transportation to place of use, dressing joints and faces of stone, mortar for joints. setting the stonework, and pointing the joints.
Rough stones at the quarry are (011unun!y classified into rubble or small stone and dimension stone. Rubble stone includes the more irregular stones :old blocks suitable for small ashlar. Dimen sion stone includes all stone required to be of particular sizes and blocks of large dimensions and definite thicknesses, as required for coursed ashlar. These classes vary according to the kinds of stone in the quarry and the specifications to be met by the stone.
Rubble stone is commonly sold by the ton free on hoard cars at point of delivery. Prices for rubble stone delivered have varied in various localities from 80.50 to 82 per ton, when wages of quarry men were about $4.50 per day and common labor 81.50. The cost is largely a matter of locality. A ton of rubble stone may lay from about 10 to 22 cubic feet of masonry.
Dimension stone and ashlar in the rough may cost from 80.50 to 81.25 per cubic foot for limestone or sandstone and $0.75 to 81.50 per cubic foot for granite, according to quality and location.
Cost of Stone Cutting.—The cost of cutting ashlar depends upon the hardness of the stone and the shape in which the blocks are received. Some stratified stones require almost no dressing on the bed joints, while other stones need every joint dressed from an irregular surface. With wages of stone cutters at 85 per day, the following may be considered average costs per square foot for cutting to 4-inch joints; granites, 27 to 35 cents; hard sandstones and limestones, 20 to 30 cents; soft stones, 16 to 22 cents. Costs of
peculiar face cuttings and of trimmings are so special to particular stones that they are of little value for general use. Sills, lintels, water-tables, and copings are usually sold by the lineal foot.
The cost of sawing and machine dressing is usually much less than that for hand dressing, and varies with the way the stone is handled and the organization of the yard.
Mortar Required.—The amount of mortar needed in rubble masonry may vary from about 15 to 35 per cent of the volume of the masonry. Rubble of squared stones with joints 1 inch thick will ordinarily require 15 to 20 per cent, according to the sizes of the stones. For random rubble, stratified stones with flat beds require less than irregular stones. In the use of irregular rubble stones, the careful use of spalLs in the larger joints reduces the amount of mortar materially, with saving in cost.
The amount of mortar needed for ashlar work depends upon the sizes of the stones. Ordinary ashlar with joints in courses 12 to 20 inches thick requires 4 to 7 per cent of mortar; random ashlar with smaller stones will require more, while with large blocks and thinner joints less will be required.
Cost of Laying Masonry.—The cost of setting stone varies with the size of the j5b, the organization of the work, and the skill of the masons, as well as with the character of the work itself. In ordinary rubble or squared-stone work, such as cellar walls or light retaining walls, a mason should lay a cubic yard of masonry in three or four hours. A helper to two masons or a helper to each mason, accord ing to convenience of work, being required to supply stone and mortar. With masons at 50 cents an hour and helpers at 20 cents, this would cost from $1.80 to $2.80 per cubic yard. In large work, where stone is handled by derricks, and rubble constructed of large blocks, the cost of placing the stone is frequently reduced to $0.85 to $1.25 per cubic yard. The cost of setting ordinary ashlar varies from about $3 to $5 per cubic yard for limestone and sandstone, and from $6 to $9 for granite.
The total cost of masonry in place, made up by so many varying items, necessarily varies within wide limits. Ordinary rubble at prices which have existed within the past few years (previous to the War), averages in cost from $5 to $7 per cubic yard. Rubble in heavy construction, usually granite, where the stone was quarried on the work and handled by machinery, has run from $5 to $11 per cubic yard. Sandstone and limestone bridge masonry, with ashlar facings and rubble backing and filling, usually varies from about $8 to $14 per cubic yard.
Gillette's " Handbook of Cost Data " gives a number of detailed statements of costs of stone masonry. Such costs vary in about the same ratio as the pay of labor employed. The unsettled state of prices and labor costs since the War make it impracticable to give costs based upon present prices.