Back Plaster. With the topping out of the chimneys the mason, who in suburban work is quite likely to be the plasterer as well, should turn his attention to the back plastering if there is to be any. This is done in several ways, a common method being to nail strips to the sides of the studs and to lath upon these, plastering the whole surface between the studs with a rough coat of plaster. (Fig. 30 a.) Care must be taken to bring the mortar well out on the studs and even then, when the studs shrink, there may be a continuous crack along the side of the stud from top to bottom. This, if it occurs, will defeat the whole purpose of the back-plastering and is so likely to occur that other means are often taken to obtain a better result. One of the best methods is to lath the house on the studding and plas ter a rough coat and then fur off with -1-inch strips and lath and plaster again for the finished work. (Fig. 30 b.) Fire Stops. In connection with the back plastering, may be done the fire-stopping of plaster or bricks, the principal points being to build up on the underpinning behind the sill to the underside of floor with brick, not only to prevent the spread of fire, but to prevent rats from going from the cellar up into the walls and so all over the house. On the top of girders the same thing should be done, and if they support partitions, the brick work should be carried up between the studs for a distance of three courses or more above the floor. (Fig. 31.) By repeating this upon each partition cap and upon the gifts of the outside frame, the whole House will be cut up into ments and the circulation of fire and vermin materially checked. In the case of a balloon frame where no girt occurs, it is customary to run the floor boards out between the studs and to build up on these with the bricks. A further precaution and a valuable one is to lay a few courses of bricks upon the bridging of partitions; this will cause any fire which may be started below, to break out into the room, where it will be discovered before it is likely to reach the story above. The spaces between stair stringers and around chimneys should also be pro tected by fire stops of brick or plaster.
Furring and Finish. As soon as the roof is on and boarded, the gutters will be put on and the roof shingling begun. The position of the gutters must be carefully noted to be sure that the edge is on a line with the roof boarding, otherwise the gable finish will not work out right. The position of the conductors should be deter mined, and the gutters set with a slight fall toward them, and holes for the lead goose-necks should be bored, in order that no water shall stand in the gutters. With the completion of the gutters the shin filing or slating of the roof can be commenced, and before the roof is completed the furring of the inside will be taken up.
Furring. Beyond the setting of minor partitions which were not needed for the support of floor beams, the principal work of interior framing will be the furring of chimney breasts, and the form ing of beams and arches. The position and size of all doors must be carefully verified, especial care being taken to allow the proper width for door casings where doors come close to the corner of any room. When the studs of all interior partitions are set up they must he bridged. This is often done by cutting in horizontal pieces be tween the studs (Fig. 32); but a better way is to cut in the pieces diagonally (Fig. 33). The chimneys must be enclosed by vertical studs, usually 2 X 3-inch or 2 X 4-inch, set flatwise and at least an inch away from the brick (Fig. 34), with an ample opening left for
fireplaces, well trussed. All door openings must also have a truss over them, and any partitions which have no adequate support beneath them should be trussed if the arrangement of doors will by any means allow it.
The ceilings will be cross-furred with s X 3-inch strips, commonly called "strapping". 'These strips should be carefully levelled and straightened, as upon their evenness depends the smoothness of the ceiling, and above all it is necessary that the strips are well nailed to every joist. Grounds are next set and angle beads for lathing, but before any laths can be laid there are a number of things to be con sidered.
Furnace Pipes. Li the first place, all hot air pipes which are not intended to be exposed must be put in position. If a hot air system has been selected the position of the pipes and registers will have been marked on the plans, but it frequently happens that in the execution, changes will suggest themselves or will be required by unforeseen circumstances, so that the superintendent should make a personal study of the piping at the building. Where it is possible to arrange it, the pipes should be run through closets, exposed to view, but this cannot always be clone, and it often happens that the chimney breasts and sometimes the partitions must contain hot air pipes. The best and safest way to do this is to make the pipes double with at least a half-inch air space between the outer and inner pipes. This is expensive and is not generally clone, but instead the woodwork which comes close to the pipe is lined with bright tin, and heavy wire lathing is used in front of the pipes instead of wood laths. Where the pipes are carried through the partition or woodwork a sleeve of bright tin half an inch larger than the pipes all around should be provided as a safeguard against over-heating of the pipes.
Plumbing and Gas Pipes. Although it is customary now to run the plumbing pipes outside of the plaster, there will be some ventilation pipes that will need to be provided for at this time. All of the enclosed gas piping must be clone before lathing. From the fact that the gas piping must be carried in almost every case to the center of the ceilings, there is need of careful watching lest the cutting by careless workmen shall weaken the joists. The specifications distinctly state that no floor beams shall be cut into, more than two feet away from their bearing, but as this means that all outlets in the center of ceilings must be reached by branch pipes between the joists, entailing more piping and labor for the gas fitter, there is a great temptation to disregard instructions, and to cut the joists for a straight run from center to center of rooms. Only constant watching will prevent this being clone. Care must be taken that the pipes are run with a continuous drop toward the meter, to allow the liquid, which will always be condensed from the gas, to run off; and for the same reason, wall outlets must be piped up from below and ceiling drops should be taken out of the side or top of the pipes. The position of all outlets must be verified, especially those which are centered in the rooms, and they must be set at right angles to walls and ceilings. This can be verified by screwing on to each outlet, as soon as set, a piece of pipe a foot or more in length and testing with a steel square No "gas fitters" or other cement should be allowed, but all pipes should be put together with red lead. The outlets to receive fixtures should be strongly secured to prevent springing or movement in the plastered work.