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erection of modern steel buildings. This means the standardization in the drafting room and the sawing, planing, and fitting by machinery in the shop of all of the heavy timbers, as sills, girders, posts, studs, joist studs, and rafters, marking each piece and distributing them at the proper lot for erection. There is a saving of labor because of the greater efficiency of power-driven machines over hand tools, and in instances where the company operates its own sawmills much material can be saved by cutting the logs the desired length. This system requires careful planning and intelligent supervision.
There are some house-building companies that carry the idea much further, not only cutting the heavy pieces to fit but also the sheathing, siding, molding, rails, steps, etc. These pieces are marked and the knocked-down houses shipped to any point in the United States.
TYPES OF FRAMES.
THE BRACED FRAME.
There are two types of frame houses; one is known as the braced " frame and the other as the “balloon" frame. The braced frame is seldom used now on account of its expense, but a short description will be given, as some of its features might be adopted advantageously under certain circumstances. In this type the sills, posts, girders, and plate are all mortised and pinned together, and the posts are diagonally braced by heavy members, which are mortised and pinned. The studs are all mortised into the sill, girder, and plate. The strength of a braced frame is independent of the sheathing, and it is therefore less liable to become distorted than a balloon frame. The braced frame was used when lumber and labor were cheap and nails were expensive. The old colonial houses were of this type, which helps to explain their remarkable durability.
The balloon frame is composed of lighter pieces and is more quickly erected. The main timbers are held together largely by spikes and the studs are simply nailed to the sill and extend from the sill to the plate, the girder being omitted. If the studs are not long enough they are spliced. In place of the girder a 1-inch by 7-inch board, called the false girder or ribbon, is nailed on the inside of the studs to support the second-floor joists. On each side of all door and window openings the studs should be doubled, and in two-story balloon-frame houses, where it is necessary for the studs to extend the full height of the wall, it is desirable to have the windows of the second story directly over those of the first. The balloon frame depends for its strength largely on the sheathing which binds the framework together, and for that reason the sheathing should be put on diagonally.
COMBINATION FRAME. A combination of the above two methods is sometimes used. The braced frame is adopted as far as sills, posts, girders, and braces are concerned, but the studs are mortised at the lower ends and are only
12 inches of horizontal shrinkable timber between these points
Scale in feet
2" by 4" sole
6" by 8"sill
2" by 10"joist
s” by 10"girder
FIGURE 7.-Incorrect method of framing a house.
spiked at the upper ends. If the siding or clapboards are to be nailed directly to the studs (the sheathing being omitted), the method of framing is very important and a combination frame should be considered.
Under the subject of “Foundations” attention was called to the evils caused by the settling of the house, and remedial measures, in so far as the foundation was concerned, were suggested. Settling is also caused by the shrinkage of timbers, and, although this can not be avoided entirely, it may be minimized by using well-seasoned timber and by erecting the house in the warm, dry season.
The most practical remedy lies in controlling the shrinkage so that it is equally distributed. This can be easily done if certain simple principles are understood and enforced. The amount that timber shrinks along the grain is imperceptible and may be ignored. The chief shrinkage is across the grain, and in ordinary spruce or white pine this may amount to one-half inch for every foot of cross grain. It is therefore important to keep the amount of horizontal timber in the outside walls approximately the same as in the interior walls. Timbers placed vertically or on end do not contribute to the shrinkage, Figure 7 shows how the above practice is ignored and figure 8 shows how the settling due to the shrinkage may be appreciably reduced.
The sill should be set in a bed of cement mortar and the bottom side should be painted with two coats of linseed-oil paint to prevent the timber from absorbing moisture from the foundation wall. The broad side of the sill should rest on the foundation wall, but the Darrow side should face down, if piers are used. The sill should be set back an inch from the edge of the wall so that a water table (see fig. 8) may be built to shed the rain that drains down the side of the house.
Special attention is also called to the method of framing around a chimney, and under no consideration should any timbers come in contact with or rest upon the brickwork of the chimney. (See fig. 6.) The 2 by 4 inch piece inserted between the studs of a balloon frame on the outside wall at the second story is known as the “fire stop.” (See fig. 8.) In case of fire it helps to prevent the fire from creeping from the bottom story or basement up between the partitions to the roof. It also helps to make the house more comfortable by preventing circulation of air between the partition walls.
ADVANTAGES OF GABLE ROOF.
When the roof slopes back from the ends of the building the same as at the sides it is called a hipped roof. The well-known gable roof and the hipped roof are the types most frequently used on small,
inexpensive houses. In large houses the size of the span affects the type of roof selected. In approximately square houses the hipped roof is very popular. Although this roof requires less material (considering the saving of gable walls) than the gable type, it is
questionable whether it is more economical. The labor on it is more expensive, because the rafters must be cut in many different lengths, and four or five ridges must be framed and flashed, as compared with the one of the gable roof. In case the attic space is ventilated, as it should be, dormer windows are necessary on the hipped roof, whereas a less expensive, plain window may be inserted in the gable ends of the gable roof. Another advantage of the gable roof is that the lineal feet of gutters, cornice, etc., is reduced one-half. Attention is called to the different effects that may be obtained by changing the direction of the ridge on a gable roof, and this resort may often improve the lighting of the adjoining houses.
NECESSITY OF A PLAIN ROOF.
The roof of the house is frequently used as a means of getting ornamental effects, but in this bulletin it is discussed chiefly as regards durability and incombustibility. A plain roof with just as few ridges and valleys as possible is advocated, because these increase the cost, and it is at the intersections that leaks frequently develop. Fancy trimmings on the ridges should be omitted.
It is important that the ridges, valleys, and chimney should be carefully flashed. Tin perhaps makes the best and least expensive flashing material, but it should be painted on both sides. A good paint for this purpose is one made of red lead and linseed oil. The chimney should be surrounded by lead counterflashings in addition to the tin-apron flashing. Flashings on valleys are frequently cut too narrow, with the result that they overflow during heavy rains and the water works its way under the shingles and leaks result. On roofs having a pitch of 45° or more the flashing should be done with strips of tin at least 18 inches wide, and on roofs of less pitch it should be at least 20 inches wide. The end joints on flashings should be locked and soldered.
The pitch or slope of a roof depends largely upon the climate and the character of roofing material to be used. In a damp, cold locality steeper roofs are required than in a warm, dry, sunny one, because the high evaporation of the latter augments the pitch in drying the roof. The roof should not be too steep, but the pitch on a main roof should never be made less than one-fourth, which means that the rise is 3 inches to each 12 inches of span.
Slate, wooden shingles, roofings composed of saturated papers or felts, finished with a coating of sand, crushed slate, or ground mica, and sheet metals are used for roofing inexpensive houses. The merits of these will not be discussed in full, but certain salient features will be touched upon.