Carpentry, Framing for a Window opening

Deciding whether or not a window would look great on that empty wall? Do it yourself and save big money! Once you have determined the exact wall placement, size and shape for your new window, shop around for a unit that is of the same brand or a close match to your existing windows. Aesthetically, the appearance of the installed window looks nicer if it matches the existing windows on the home. Once purchased, determine the rough opening size. Most manufacturers list the rough opening of the unit in the literature provided. This measurement is typically a 1/2 inch larger on all sides of the unit. Measure the wall and, with a pencil, mark the rough opening size for each side of the unit. Determine stud location on the outer sides of the unit. In most cases, studs are 16 inch on center. Trace a level line from floor to ceiling on the center of each stud. The baseboard trim should be removed safely at this time and stored away for re installation later. Remove the drywall by using a utility knife and cut along the ceiling and each stud. Your opening is now considerably larger than the rough opening, however, the stud will act as a nailer to accommodate both new and existing drywall. All exterior walls are load bearing and require support above the unit to carry a second floor load or roof load, this support is generally called a header. The width of the unit would determine the size of the header needed to carry the load. In most cases for units less than 5 ft. a double 2x10 header would be sufficient. Using a circular saw, cut the 2x10's and a 2x6 (or 2x4 depending on the width of your exterior wall) 6 inches larger than the rough opening. The 2x6 will be nailed below the 2x10's and is a called a pack down. Using 12d penny nails secure a 2x6 stud 3" wider on both sides of the rough opening. Remove the 2 studs remaining in the center of the opening and secure the two 2x10's to the top plate. Install the packdown and measure for jacks which will support the header and butt to the packdown. A jack typically measures 81 3/4" from bottom plate to packdown. Install two jacks on both sides under the packdown on both studs using 12d penny nails. Your width is now established. Next measure from the pack down towards the sub floor and mark the rough opening for the height of the window. Measure down an additional 1-1/2 inches to accommodate the window sill. The distance remaining is the measurement in which you will cut the cripples. The cripples are the 2x6's which support the sill. Cut the 4 2x6's for the cripples and install 1 on each and the other 2 on the 16 inch stud layout. Next cut the sill(2x6) the measurement of your rough opening width and install to the cripples using 12d penny nails.
The window opening is now created. Stay tuned for removing the exterior and installing the new window.