Openings In Framework. Studs in outside walls are set without reference to openings for doors and windows. Such openings are cut and headers and stools placed after the walls are up and ready for sheathing. The seeming waste occasioned by this method is slight since the cut-out material is available for headings, etc. Most carpenters make a story pole to be used in laying off window and door heights in cutting out studs. This is nothing more than a piece of l"x 2" or l"x3" stock with the heights of the openings from the rough floor or from the joists, where the rough floor is not laid, marked plainly thereon. This pole is placed alongside the stud to be cut and the mark transcribed from pole to stud.
Beginners are frequently troubled in determining the proper opening, even when the size of the window is specified. In general, carpenters plan to have the studs on either side of an opening, either door or window, so set that the outer edges of the exterior casings will break upon their centers. Windows are specified by the width and height of their glass and the number of divisions or lights, width always being specified first. The distribution of excess measurement due to the meeting rail, top and bottom rails, side rails or stiles is shown in Fig. 36. Rail and stile widths and sash thicknesses will vary from those given when any very great
Fig. 36. Estimating Window Openings.
increase in size of window is made. Manufacturers of sash and doors provide catalogs in which stock sizes are listed.
Fig. 37. Framing Wall Openings.
Estimate an opening vertically, Fig. 36, thus: Sill, 2"; sub-sill, where frame is made with one, 1"; bottom rail, from edge to bottom of rabbet, 3"; glass in lower sash, 34"; meeting rail, from rabbet to rabbet, 1"; glass in upper sash, 34"; top rail, 2"; space for head jamb and lugs of side jambs, 2" or 3"; total, 79". A carpenter would say, "Add 11" to the glass measurement to get vertical height between stool and header." Window sashes with muntins require an addition of 1/4" for each muntin. The thicknesses of header and stool must be considered in addition to the measurement just mentioned when studs are sawed, Fig. 37.
The width between studs would be estimated thus: Width of glass, 28"; width of stiles, from rabbeted edge to outer edge, 4"; width of casings, 8"; total 40", distance from center of stud to center of stud. Comparing this with the width of glass it will be seen that the difference is 12". A carpenter, therefore, makes use of a general rule: Add 10" to the glass measurement to get distance between studs, where a 4" or 4½" casing is used with this type of window frame.
For the 3' x 7' door, Figs. 37 and 38, estimate the opening as follows: Height of door, 7'; allowance for rough floor, ¾"; finish floor, ¾"; threshold, ⅝" to ¾" head jamb and space for lugs of side jambs, 2" to 3"; total from joist, may be 7' 5".
For the width of opening estimate: Width of door, 3'; width of casings, at 4½" each, 9"; total spacing of studs center to center, 3'9". Distance between studs will be 3' 7". This will leave space enough to put the doubling studs on each side between header and floor. Since locations of openings in the main frame, both window and door, are dimensioned to the centers of the openings, it is easiest in laying off to estimate from the center each way rather than to estimate total width.
After these openings are made, the frame of the house may be covered with sheathing, or the roof may be framed; both orders of procedure are common.
Fig. 38. Threshold Detail.