Windows in brick or other masonry walls are in every respect similar to windows in frame walls, the only difference being in the arrangement of the jambs, heads, and sills.

Fig. 337 shows a section taken horizontally through the jamb of a double-hung window in a brick wall. At A is shown a section through the wall itself. It will be seen that there is a sort of rabbet made in the back part of the wall in which to set the window frame, and that the front portion of the wall projects in. front of the frame. This is done in order that there may be a certain amount of solid masonry which will cover the joint between the wall and the frame and prevent the wind from driving in between them through this joint. The distance B is called the "reveal" of the window, and is usually made 4 inches, but is sometimes 8 inches. The depth of the rabbet in which the frame sets may vary considerably, but is usually 2 to 4 inches.

Fig. 336. Mullion Construction for Fig. 335.

Fig. 337. Horizontal Section through Jamb of Double-Hung Window in Brick Wall.

From the face of the brick reveal to the face of the pulley stile D the distance C may be made anything, according to taste, but is best made about 2 inches. The pulley stile D is made in the same way as for windows in frame walls. E is the outside casing, which sets as close as possible against the brickwork, and G is a piece called the "back lining," which forms the back of the weight box. In all other respects the construction is the same as described for windows in frame walls. At H is shown an inside sash which can be put on in winter for additional protection against the cold. It is usually made as a casement sash to open in. As will be seen, it is hung on a rabbeted piece K, which also forms the jamb lining of the window on the inside and receives the inside architrave which is indicated at L. M is the furring on the inside of the brick wall and N is the plastering. The space 0 is filled with rough blocking, and the space P should be well caulked with oakum, or other substance, to keep out the cold. F is a piece called a "brick mold" or sometimes, a "staff bead," which is put in to cover up the joint, between the frame and the brick. It may be of any desired form, being sometimes made a simple square block or strip on which the window blinds are hung.

Fig. 338 shows a section taken vertically through the head of a double-hung window in a brick wall. At A is the masonry lintel which covers the masonry opening. It is usually of stone. The distance B is the same as the distance B in Fig. 337 and the distance C is also the same as the corresponding distance in Fig. 337. D is the yoke, the same as for a window in a frame wall, with the outside casing E and the staff bead F. G is the wood lintel which is usually placed behind the stone lintel over the masonry opening. This section also shows an inside or winter sash at H, the same as in Fig.

Fig. 338. Section through Head of Double-Hung Window.

337, with the piece K arranged to receive it and also to receive the edge of the inside architrave L. M is the furring on the masonry wall, and N is the lathing and plastering, the plastering being covered by the architrave L.

Fig. 339 shows a section taken vertically through the sill of a double-hung window in a brick wall. A is the stone sill in the outside of the masonry wall, and should be wide enough to extend into the wall and under the wood sill far enough to allow the latter to lap over it about 2 inches. The wood sill, shown at B, is usually made wide enough to receive the staff bead, so that the width of the stone sill needs to be about the same as the depth of the reveal at the jambs, or the stone lintel at the head of the window. The sill B rests, on the inside, on a piece of rough timber built into the wall, as shown at D in the figure. The sill should have a "wash," or slope outward and downward, of about 1 1/2 inches to the foot. In the figure, C is the lower rail of the lower sash of the window, which must stop against the sill and be made tight in some way. The figure shows both the sill and the sash rabbeted, but very often the sash is not rabbeted. The piece E forms the finish on the inside corresponding to the stop bead at the jambs and head, and serves to cover up the rough sill. The piece F also serves the same purpose. L is the rough brick wall with the furring at M and the plastering and lathing at N, and the space between the rough sill and the plastering is covered and finished by the piece G, or the stool. Underneath the stool is placed the apron, as shown in the figure at H.