The framing of porch floors has been described in Section 49. The rafters of the roof are supported by a plate or beam spanning from post to post or from post to wall, and usually enclosed by the cornice or by a false beam built up of 7/8-inch pine boards. When the finished posts are round they usually form the support for the roof ; if the posts are square a rough post is often set up to support the plate and a finished post built around it. Hollow posts should never be used to support any great weight.
•This illustration was first published in the American Architect of March 14, 1885.
Porches may be built and finished in so many different ways that it is impossible, in a work of this character, to allude to more than a few general features.
To begin with, the floor should rest on a solid foundation, brick or stone piers being the best, and all vertical wooden supports should be set with the fibres running vertically. All joints should be made so as not to be exposed to the weather, and the various parts should be neatly joined and well nailed together.
Porches built against brick or stone walls should have the upper portion secured to the wall by ¾-inch bolts set in the wall as it is built.
Flooring. - For the flooring hard pine should be used, and for first-class work the boards should be not over 4 inches wide, 1 1/8 inches thick and quarter sawed, and, of course, free from knots or sap.
In regard to using matched flooring custom varies in different portions of the country. In the New England States it is customary to lay porch floors with open joints, the boards having square edges and being set about 3/16 of an inch apart, the nails being driven through the top. In other sections of the country matched flooring is generally used and nailed in the joints (blind nailed). The author is inclined to favor the open joint flooring, especially in localities where there is much rain or snow, although in climates like that of Colorado the tight flooring is perhaps more satisfactory. When the boards are matched they should have the tongue painted with thick white lead and oil just before the boards are laid, and the floor should pitch from the wall outward, about 1 inch in 8 feet, so that water will not stand on it.
When the sides of the porch are enclosed with a solid wall it is a good idea to run a narrow strip around the outside edge of the floor with a groove worked in and graded to form a gutter, and with holes bored through to let out the water.
When the porch is open the outer edges of the floor are finished with a nosing and cove, as shown in Fig. 161. Very often the ends or sides of the floor boards are rounded and the cove moulding placed underneath, and with open floors this is the best way, but with tight floors a solid moulding nailed to the edge of the floor, as in Fig. 161, makes a neater job.
The steps, if of wood, should be supported on plank strings set from 16 to 20 inches apart and resting on a flat stone or foundation wall at the bottom. The treads should be 1 ¼ inches thick, with the front edge rounded for a nosing, and the ends (when open) finished with a nosing planted on and mitred at the corners ; a cove moulding is usually placed under the nosing. The ends of the steps are generally finished with a triangular panel, the panel being solid or made of lattice, according as it is small or large.
The sides and front of the porch beneath the floor, when of wood, are generally finished with wide pine casings with lattice work in the panels. There are two methods of forming this lattice work, the cheaper and more common one being to use lattice strips of stock size (¼x1 1/8 inches) nailed over each other, as shown in Fig. 160, A, the vertical strips being on the outside. The strips should be set so that the openings will be square and equal to the width of the strips, and the strips should be nailed together where they cross.
The other method is to use strips ¾ inch thick and about 2½ inches wide and halve them together at the intersections, giving the appearance shown at B. This style of lattice undoubtedly looks more substantial than the other, but it costs two or three times as much. In putting up the lattice it is customary to nail the strips to the rough work of the porch and then nail the casings over the strips, but it is better, with a porch like that shown at A, to frame the casings together and to nail the strips to the back of the frame thus formed, so that it can be taken out should occasion require.
126, Superstructure. - In regard to the superstructure, the construction or putting together of the finish will depend a great deal upon the style of the porch, many porches being finished with cornice and gable to correspond with those on the house.
At the present time porches of the colonial or classical type are very much in vogue. These usually have turned posts which rest either on a pedestal or on the floor, as shown in Fig. 160. The choice of style is largely a matter of taste. When a post stands on a pedestal its diameter is decreased, and hence it can be turned from a smaller stick, and the decrease in the diameter also lessens the height of the cornice above, the proportions of the column and cornice being approximately those given by Vignola.
Posts less than 12 feet high are almost always turned from a solid timber, redwood or cypress being the best woods for the purpose, as they can be obtained in large sizes and free from knots, besides standing well.
The caps and bases are commonly turned out of pieces of planks with the grain horizontal. To make a neat job, the timber from which the post is turned should be at least 1 inch larger than the diameter of the column, so that the fillet at the top and bottom can be turned on the post. The columns will crack and check less if they are bored longitudinally through the centre.
The rails and balusters may be of such size and shape as suits the designer. Rails less than 4x4 inches in cross-section are usually "stuck" from a single piece of wood ; when larger than this it is best to build them up.
It is a good idea to bevel the top of the rails slightly so that water will not stand on them, and a beveled top to the lower rail holds the balusters more securely. For residences not too pretentious in style plain balusters 1¼ inches square, or 7/8x1 ¼ inches when set about 1 ¼ inches apart, make a neat and inexpensive railing. The builders of the better colonial residences generally used balusters 4 or 5 inches in diameter and a correspondingly heavy rail, as shown at B, Fig. 161, and such balustrades are still used. They are, of course, much more expensive than the other railing shown. The common size for turned balusters for porch or piazza railings is 1¾ inches. The usual height of the rail from the floor is 2 feet 6 inches. The lower rail should be kept 2 inches above the floor to facilitate sweeping, blocks being placed under the rail at distances of 4 or 5 feet to keep it from sagging.
When short posts are used they are usually nailed to the floor, and if they do not come at an angle of the porch should be further strengthened by iron angles screwed to the floor and post.
The construction of the cornice of porches such as have been described is illustrated by the enlarged section, Fig. 161. It should be noticed that the plate which supports the rafters is placed directly under the rafters and is supported over the columns by uprights formed of studding. The lower plate is suspended from the upper one between the posts, but when the fascia is on the cornice is really self supporting.
It is always desirable to provide the porch roof with gutters and conductors. When the roof is flat the gutter may be formed in the roof as shown. A pitch of \ of an inch to the foot is sufficient for a tin roof.
If there is a railing above a tin roof the best method of securing the posts, if square and built up, is to extend a rough scantling from the plate 12 inches or more above the roof and turn the tin up around it, soldering the tin at the corners. The finished post is then set over it and is securely held, and without chance of leaks through the roof.
If turned posts are to be used they may be extended through the roof in the same way and the top of the tin turned into a saw-cut in the post, which should then be filled with putty, or a block of wood about 1 3/8 inches thick and 1 inch larger than the post may be nailed over the tin roof and then covered with tin, which should be soldered to the roofing. The post may then be toe-nailed to this block. Angle posts are braced sufficiently by the railing without extending through the roof, but where intermediate posts are used it is best to carry them to the plate.
Movable Floor, - If the porch roof is to be used as a balcony it should be covered with tin or copper, and a movable flooring, made of slats and cleats, laid over it. The slats should be of 4-inch square-edged flooring, laid ¼ inch apart and nailed to 1 3/8-inch or 1 ¾-inch cleats, which should be blocked up from the tin, but not fastened in any way. This flooring should be made in sections convenient for handling.
Although not a matter of construction, a very common mistake made in designing residence porches that face the South or West is that the bottom of the cornice is placed too high above the floor, so that the roof does not protect from the sun during the afternoon.
Unless the porch is very deep the clear opening above the floor should not be more than 8 feet if the porch faces the West. On the east side of the house this is not a matter of consequence.