"These floor timbers are simply two-inch planks, nine inches wide. There is a pile of them," said Mr. Brookbine, pointing to the lumber. "They are to be placed sixteen inches apart, the sills being notched, or mortised, to receive the ends. These joists must be bridged."
"Bridged?" queried Ben Ludlow.
"This must be done before the floor is laid, for we can't get at the joist afterwards. Short pieces of board are nailed from the upper side of one timber to the lower side of the next one, the ends being sawed at the right bevel. Another piece is nailed in close to it, at right angles with the first. A pair of bridge-sticks must be put in every five feet. They are used to prevent the narrow timber from canting, thus giving a firm and solid floor.
"The next thing is to lay the floor; that is, we nail down boards over all the timbers. This will make the lower floor. Now, I may say that the framing for the end of the building where the docks are must be adapted to their shape. The floor-timbers of the lean-tos for the dressing-rooms will be supported by braces above and below from the posts.
"Now, we will suppose that the entire floor, except the docks, is laid, and we have a platform ninety-six by forty to stand upon. Before the sills were put in place, they will be mortised to receive the tenons at the ends of the posts, and of the braces. Now we are ready to return to the sections of the frame.
"To each section there are three posts,—one at each side, and one in the centre of the building. On the upper ends of these posts rest the plates;" and the instructor drew the parts as he described them. "They connect the posts at the top, as the sills do at the bottom. About on a level with the hall-floor are timbers, called girders, joining the middle post with the outside ones. The sills, the plates, and the girders are the principal timbers, and are the same in all the sections.
"In every corner there is a diagonal brace, forming a right-angled triangle with a base and a perpendicular of three feet. We shall mortise for these braces, though of late years many carpenters simply spike them in their places. Between the sills and the girders, and between the girders and the plates, are the studs. They are made of four-by-two stuff, or, in other words, of two-inch plank, four inches wide. The sills, girders, and plates are mortised for them, and a two-inch tenon cut at the end of each stick. Where windows come, short studs are put in above and below them. They are placed sixteen inches apart. This completes the frame below the roof."
"Then we are ready to go to work," said one of the boys.
"Not yet, for you don't expect the sections to stand alone. The frame of the first section will be put together with the bottoms of the posts at the mortises they are to occupy. It will be no easy job to get it up to a perpendicular; but it can be done with pike-poles and a derrick, with no little rigging. When we get it upright, the tenons will drop into the mortises, and we have to stay it in position with braces and ropes. Then we raise the second section in the same manner. There are plates and girders on the sides as well as the ends of the building. While the two sections are held in position, the girders and plates are put up to connect them. The studs and braces are put in place, as in the end section.
"All the large timbers are pinned together. You will have a nice time in making a cord or two of these pins. They are about an inch in diameter, made a little large for the hole, so as to fit it snugly. We pin the braces so that they will hold both ways, but the studs are not fastened at all, for the tenons cannot get out of the mortises."