194. When double floors are used, as should always be the case in the better class of dwellings, the upper or finished floor should not be put down until the plastering is thoroughly dry and most of the standing finish in place, and when hard wood floors are used they should not be laid until all the other carpenter's work in the room is finished.
When there is to be only a single floor it is customary to lay the floors that are to be carpeted, before plastering, leaving the hard wood floors or those that are to be finished until after the plastering is dry.
Woods Used for Flooring. - For floors that are to be carpeted spruce boards are commonly used in New England, while in the Middle and Northwestern States pine is generally used. In the Trans-Mississippi States and in the Southern States hard pine is more commonly used. For kitchen floors, and wherever a good wearing floor is desired without going to the expense of hard woods, Southern yellow or Georgia pine may be used, culling out all boards containing sap or large streaks of dark turpentine, as the turpentine soon crumbles away, greatly marring the appearance of the floor. For floors that are subject to a great deal of wear, maple is generally considered the best wood, while for parlor and hall floors oak or parquetry flooring is generally preferred. Besides these woods, birch is used in some sections of the country, and it makes a very pretty flooring. For all floors that are not to be carpeted quarter-sawed flooring should be specified, as bastard boards will sliver and warp.
Matched Flooring. - If only a single floor is used it is absolutely necessary that the boards be matched to prevent currents of air from coming up from the spaces between the beams, and for oak or other ornamental floors it is also necessary that they be matched, so that they may be blind nailed. For other floors matching is not really necessary, and in New England it is not customary to match any but hard wood flooring. Instead of matching the spruce and hard pine flooring the boards are carefully jointed or planed so that their edges will come tightly together and the nails are driven in from the top and sunk with a nail set, if the floor is to be dressed off. This makes a better floor than the ordinary matched flooring. In the Western States nothing but matched flooring is seen, although a great amount of the flooring is so poorly matched that it cannot be made to come together without rejointing by hand.
Widths and Thickness. - For a floor that is not to be carpeted the width of the boards should not exceed 4 inches,* and for a first-class oak, maple or birch floor 2 ½-inch flooring should be specified. For carpeted floors 6-inch widths will answer, if a good quality of soft pine or well-seasoned spruce is used, otherwise 4-inch flooring should be specified, for if a 6-inch board warps much it will form ridges which will cause the carpet to wear at those places. Ordinary flooring is J of an inch thick, the bottom side being left rough, but for stores, public corridors and similar places 1 1/8-inch flooring should be used, both for stiffness and durability. The better qualities of matched flooring are usually grooved on the underside, either as at A or B, Fig. 334, to make it conform to the floor and to prevent warping.
* Flooring is commonly designated by the width of the board from which it is stuck, 4-inch jointed flooring, measuring about 3 8/4 inches, and matched flooring, 3 3-16 inches on top.