CHAPTER X CONCRETE RESIDENCES The Use of Concrete for Residences.-Best Method of Obtaining Architectural Effects. Stucco and Reinforced Concrete for Residences.-The Edison Poured Concrete House: Cost of Different Types of Residences Compared. As stated in the previous chapter, the architectural treatment of concrete, until recent years, was limited to an attempted imitation of stone masonry, which tended to cheapen its appearance and to destroy its character. As an imitation of stone, concrete is not an artistic success. There is a sameness to its appearance, an air of sombreness, an absence of light and color that destroys its architectural value. Within the present century the secret of the artistic use of concrete has been revealed, and with this discovery has come such recognition by architects and owners alike, that concrete has already taken its place within the front ranks of building materials, and its growing use is indicative of a future whose possibilities and benefits to humanity are transcendent. The secret of the successful use of concrete for architectural purposes consists in such treatment of its surface as will serve to bring out its true character and to reveal its hidden beauties. These methods are in part described in the chapter on "Artistic Treatment of Concrete Surfaces," and consist in the use of carefully chosen aggregates; tooled, scrubbed, etched, or pebble-finished surfaces, stuccos of varied tints and textures; the artistic use of half-timber framing, of columns, cornices, pediments and balusters to lend variety; and an attractive shingled or tiled roof to form an effective covering. Concrete is now employed in the construction of all classes of residences, such as bungalows, costing from $500 to $1,000; cottages, from $1,500 to $2,500; moderate priced houses from $3,000 to $5,000; and palaces in which the cost of construction requires five, six, or even seven figures for its expression. Kinds of Concrete Residences.-In these different classes of residences, Portland cement mortar and concrete are used in one or more of the following forms: 1. Hollow concrete blocks. 2. Monolithic concrete. Concrete Block Residences.-Hollow concrete blocks have outnumbered all other forms in which concrete is employed in residential construction, owing to their cheapness and ease of construction. Their description and manufacture will be found in Chapter XIII. Early manufacturers of concrete blocks were unfortunate in trying to mould the surfaces in imitation of quarry-faced stone, and the effect of their efforts was to produce a structure without beauty or variety. "A rock-faced stone is the result of an actual treatment of the stone with tools, and no two rock-faced stones are alike. There is variety to the surface." But with concrete blocks the variety is lacking. "Even when several rock-faced moulds are used and the blocks are made of different patterns, it generally happens that several having exactly the same face from the same mould come together, and that is exceedingly noticeable." Surface Finishes for Block Residences.-The best architectural effects in concrete block residences are produced with the following surfaces: 1. Perfectly plain surfaces. 2. Roughened, or pebble-finished surfaces. 3. Surfaces produced by casting in sand moulds. 4. Surfaces of pure white color or delicately tinted. Some of the finest, as well as the least expensive residences are now constructed of plain blocks, the façades being relieved by columns and cornices in moulded concrete, the roofs covered with ornamental tiles of red or other warm tones, and the piazzas having concrete rails and balusters of appropriate design. Roughened surfaces are produced by scrubbing, etching with acid, and treating with wire brushes, the object being to destroy the film of surface cement and to expose the aggregate. By the use of granite chips, colored gravel, crushed marble, or coarse white sand, various effects are obtained, and the architect who possesses originality and a knowledge of the possibilities of his material, can produce striking and artistic effects at a very moderate cost. will be treated further in Chapter XII. These Casting in sand moulds is generally confined to mouldings, balusters, columns, and other ornamental features. "Sand moulding gives, perhaps, the handsomest ornament of any kind of moulding process, the surface texture and detail of the block being especially fine."— (Gillette.) Surface tints are best produced by the use of colored gravels. Pure white surfaces are obtained by using facing mortars composed of white limestone or crushed white marble and white Portland cement. Such mortars can also be tinted with delicate colors by the use of appropriate pigments. Monolithic Residences.-Houses having solid walls of monolithic concrete are best treated by making the surfaces of the walls unbroken without attempting to imitate masonry or joints in stones. The following methods of surface treatment, which are more fully explained in Chapter XII, are well adapted to such construction: 1. Spading the concrete so as to cause the grout to flush to the surface of the forms. This prevents the exposure of the aggregate and any defects can be remedied by trowelling and grouting after the forms have been removed. 2. Roughening the surface by scrubbing, etching with acid, tooling with bushhammers or pneumatic hammers, etc. 3. Use of colored aggregate or of granite chips, white quartz pebbles, or other special materials which are exposed by scrubbing or tooling. 4. Surfacing with mortar or stucco. 5. Tinting. Stucco Residences.-Any mortar employed as an exterior surfacing for walls is called stucco. Cement stucco is extensively used both for renovating old buildings and improving their appearance and in new construction. The methods of application are fully described in the succeeding chapter. The classes of residences in which a stucco finish is of advantage are as follows: 1. Old houses composed of wood, stone, brick, concrete, or other materials in which the surface is worn or decayed. 2. New houses composed of wood, stone, brick, concrete, or other materials, in which the surface is left rough or unfinished. 3. Houses having hollow walls of expanded metal, terra cotta or concrete tile, or other fabric, and covered inside and out with mortar or stucco. Portland cement stucco is easily applied to any material such as wood, brick, stone, etc., by covering the surface with a metal fabric over furrowing strips to serve as an anchorage for the mortar. Wooden lathing can also be employed for this purpose, and in the case of frame houses spaces can be left between the boards to serve as a key. Stucco is composed of: (a) cement and sand; (b) white Portland cement and either white sand, crushed white quartz, ground marble, or ground white limestone; (c) cement and granite chips; (d) cement and colored gravel; (e) cement and pebbles, etc. White stucco is also readily tinted with delicate colors by the admixture of colored pigments. Concrete for residences, whether in the form of hollow blocks, or monolithic walls, requires waterproofing. Basement walls should be surrounded by a bituminous shield, or a waterproofing compound should be mixed with the cement employed in the blocks or walls since it is desirable to render the entire exterior surface as impervious to moisture as possible. In old leaky buildings, a coat of damp-resisting paint on the exterior surface will be effective. Reinforced Concrete, which is extensively employed in factory construction, is coming into use for dwellings in order to permit of lighter walls and partitions. The reinforcement is chiefly in the form of expanded metal or other fabric which is nailed to the studding on both sides, thus forming a support for the plastering. In pretentious houses, rods are also employed to distribute the loads over foundation areas and to prevent temperature cracks. Concrete beams are employed only to a limited extent in residences, as the interior joists are almost invariably of wood, as are also the floors, purlins, rafters, and roof trusses. While this is the present practice, it is, however, no criterion of the state of the art a few years hence, when it is probable that the "all-concrete" house will have ceased to be a novelty. Special Architectural Features.-At present concrete is used to a limited extent for roofing purposes in the form of slabs and tiles, although red terra cotta tiles and wooden shingles are chiefly employed for pitched roofs and tin plates or gravel for flat roofs. Concrete houses, especially those of a suburban character, are frequently built with a prominent roof of steep pitch, large piazzas, bay-windows and the English half-timbered construction above the lower stories. This consists of wooden strips around the windows forming the trim and radiating from the upper windows to the roof. These strips are also used as mouldings and serve to bring out the lines of the gables, adding much to the appearance of the dwelling. Other decorative features of concrete houses are the columns,, rails, and balusters of the piazzas which may be of wood or concrete, preferably the latter; the free use of dormer windows in the roof, chimneys of concrete blocks or of monolithic construction in harmony with the general design, horizontal mouldings between the stones, prominent lintels, and massive cornices. The use of concrete in interiors is at present confined chiefly to stairs, panels, fireplaces, and bath rooms. Stairs are reinforced with bars and surfaced with a white mortar or are tinted to harmonize with the woodwork of the halls; fireplaces are built of concrete bricks moulded and tinted to any desired shade; while concrete slabs and tiling or mosaic laid in white Portland cement mortar is used for mosaic floors, wainscoating, bath-rooms, and fireplaces, taking the place of Keene's cement which it excels in strength and durability. Edison Cast Concrete House.-Thomas A. Edison, the electrical wizard, has experimented for several years in developing a substantial and cheap house of cement, and has published the following particulars of his work: "I believe a cement house can be built by machinery in lots of 100 or more at one location for a price which will be so low that it can be purchased or rented by families whose total income is not more than $550 per annum. My experiments have proven that it is possible to cast a house complete in six hours by pouring |