This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
Detail of General Window Frames. Fig. 45 shows the method of laying out a full-size detail of a window box. Such a drawing is one of the first things usually given to a draftsman on entering an architect's office, and one of the most important details of house building to become acquainted with. The drawing shows an elevation of the lower left-hand corner and upper left-hand corner of the window-frames seen from the outside. The lower part of the drawing shows a section through the window sill. Taking the scale of 6 inches shown at the top of the drawing, it would be found that the window sill can be made from 2-inch stock finished about one and three-quarters inches thick. On the outside, next to the clapboards, is a bed-moulding, and the slope of the sill forms a good drip to throw off water. The clapboards are housed into the under side of the sill. The sill rests on a 3 by 4 or 4 by 4 horizontal stud under the window opening. The inner side of the sill is cut to come on a line with the finished plaster. The plaster stop or ground, which is either three-quarters or seven-eighths inch thick, according to the proposed thickness of the plaster, is nailed on to the 3 by 4 stud. The space between the stud and the sill is frequently filled with mortar. At the left of the drawing is shown a section through the side of the window box.
The outside architrave is arranged on the outside of the boarding; and a back band, or moulded strip, forms a finish around the outside edge. The layers of paper are generally run on the boarding under this outside architrave; and sometimes zinc flashing is used in very exposed positions, being turned up against the outside architrave. The small three-quarter round bead shown in the drawing may be omitted. The 3 by 4 stud is set so as to leave space for the weights. It is a good rule to remember that the distance from the stud to the glass opening is 5 inches, and the distance from the sill stud the same. The distance from stud at window head to glass opening is 4 inches.
The pulley stile is of hard pine; and the parting strip, or stop-bead between the two sashes, is also hard pine. Between the outside architrave and the sash is put in a small screen strip, to give space enough for a mosquito screen between blinds and sash. On the inside of the sash is a stop-bead, which forms a part of the interior finish and covers the rough part of the window frame.
The upper part of the drawing shows a section through the window head. Sometimes the window frame head is made of thinner dock than that shown. This completes the rough window box as it is shipped from the sash factory to the building. At the building, it is nailed in place against the rough boarding; and later the sash, which come a little too large for their position, are fitted into place. Sections horizontally and vertically are shown through the sash, including meeting rail and muntins. The sash at the sill is wider than elsewhere, and underneath is usually beveled where it comes against the finished window stool, so that it will shut tight. There is also usually a groove underneath, to intercept any water that may blow in. The meeting-rail may be made on the outside sash, to drop below the meeting-rail on the inside sash, forming a drip which will prevent the water washing down on the glass of the lower sash.
The inside finish is frequently included on the general interior-finish drawings of the building, and is not always sent out with the window-frame details. The window stool is shown on the drawing, with a small space underneath where it comes against the sash, which forms a slight interruption for any water that may pass the other groove. The apron is nailed onto the sill and plaster stop; and a moulding is generally run under the window stool where it joins the apron. A back band may be laid around the inside architrave, against the plastering; or the inside architrave may be all one piece.
Fig. 46shows several variations from the details of window frames illustrated in Fig. 45; and these can be still further varied if desired; or a combination of the parts may be made, taking certain details from each detail given.
The frames, unless otherwise shown, are usually made of white pine. Pulley stiles and parting beads are made of hard pine.
The pulley stiles are seven-eighths inch thick, tongued into the outside casings, as shown in the section through the side of the window box. The parting or stop beads are seven-eighths by one-half inch in size; sometimes they are made seven -eighths by three-eighths inch, the latter giving more room for the screen strip.
When two-coat work is specified for plaster, the plaster stops are generally three-quarters inch thick; when three-coat work is used, generally seven-eighths inch thick. Very often the window box is completed by ground-casing either three-quarters or seven-eighths inch thick, as shown in Fig. 47; in this case no ground or plaster stops are necessary around the window frames. The yoke or window-frame head is generally made one and three-eighths or one and one-half inches thick. The sills are set to pitch one and one-half inches. Care must be taken to see that the blinds are made sufficiently long to fit, as stock frames are frequently made with a slope of not over one-half inch in four inches. The outside casing - or outside architrave, as it is sometimes called - may be set either flush with the boarding or outside the boarding. When it is set flush with the boarding, the shingles may be carried directly across the joint, and finished against a back band, which comes around the outside of the window frame. The outside casing is generally seven-eighths inch thick, and five inches or sometimes four and one-half inches in width. In certain cases it is made of one and one-eighth inch stock, when it is to be set outside the boarding. Sometimes, instead of the back-band shown, an architrave made from one and one-eighth to one and three-quarter inch stock is planted on the outside casing. This would show the distinction between the outside casing and the outside architrave. The method of using a ground casing and outside casing flush with the boarding is inexpensive, and therefore in quite common use. It does not give sufficient room for a screen strip, and does not make a very tight casing where the pulley stile connects with the sill.