The partition walls are made 4 inches wide, the same as in the outer walls, except in the case of so-called "furring" partitions. These are built around chimney breasts and serve to conceal the brickwork and furnish a surface for plastering. They are formed by placing the studding flatwise, in order to make a thin wall; and as it is usually specified that no woodwork shall come within 1 inch of any chimney, a 1-inch space is left between the brickwork and the furring wall. It is possible to apply the plaster directly to the brickwork, and this is sometimes done, but there is always danger that cracks will appear in the plastering at the corner A, Fig. 120, between the chimney breasts and the outside wall. This cracking is due to the unequal settlement of the brickwork and the woodwork since the plastering goes with the wall to which it is applied. The method of constructing a furring wall is shown in plan in Fig. 121. A A are the furring studs, B is the plastering, and CC the studding in the outside wall. The arrangement without the furring wall is shown in plan in Fig. 120. If there are any openings in the furring wall, such as fireplaces, or "thimbles" for stove pipes, it is necessary to frame around them in the same way as was explained for door and window openings in the outside walls. See Fig. 122. A A are furring studs, BB are pieces forming the top and bottom of the opening. If the outside walls of the building are of brick or stone, a wood "furring" wall is usually built just inside of the outer wall; this furnishes a surface for plastering and for nailing the inside finish. The studding for these walls is 2 X 4 inches or 2 X 3 inches or 1X2 inches set close up against the masonry wall and preferably spiked to it. See Fig. 123. Spikes are usually driven directly into the mortar between the bricks or stones of the wall, but sometimes wood blocks or wedges are inserted in the wall to afford a nailing surface.

Fig. 120. Plan Showing Plaster Applied Directly to Chimney Brickwork

Fig. 120. Plan Showing Plaster Applied Directly to Chimney Brickwork.

Fig. 121. Plan Showing Construction of Furring Wall

Fig. 121. Plan Showing Construction of Furring Wall.

Fig. 122. Furring Strip Frames Around Openings

Fig. 122. Furring Strip Frames Around Openings.

Fig. 123. Furring strips on Outside Wall

Fig. 123. Furring strips on Outside Wall.

Wherever a wood partition wall meets a masonry exterior wall at an angle, the last stud of the partition wall should be securely spiked in the masonry wall, to prevent cracks in the plastering.