Installing windows and doors is the next step in establishing the integrity and weather-tightness of the house envelope. While the number and style of windows and doors specified for your project are key aspects in defining your home’s appearance, the technical specifications and the manner of installation also have tremendous impact on the quality of light, ventilation and energy-efficiency of your home.
Windows and doors are among the most highly engineered and costly products in the entire project. A house with many windows and doors usually costs more to build than the same size house with an average number; more labor and material are required.

Door Styles
Doors are classified in several different ways: In choosing, you must make distinctions between exterior and interior doors. Exterior doors are thicker than interior doors and are fabricated with waterproof adhesives. Never specify an interior door for an opening that’s exposed to the weather.
Doors are also classified by appearance, which is related to their manner of construction. Most builders recognize three basic styles: sash, flush or louver doors. Sash (also called panel) doors consist of a frame of horizontal rails and vertical stiles. This outer border surrounds one or more inset or raised panels. Wood entry doors, French and patio doors commonly feature this type of construction. Flush doors, an economical option or basement and secondary entries, have a flat face on both sides. Flush doors can have either a solid or hollow core; the latter are acceptable for interior use. Louver doors, commonly used on interior closets and laundry rooms, resemble elongated shutters.
Doors are available in two standard heights: 6 feet, 8 inches and 8 feet. Interior door widths start at 1 foot and go up in 2-inch increments to 3 feet wide; standard-width exterior doors start at 2 feet, 6 inches and go up in increments of 2 inches.
Another way to classify doors is by the manner in which they open and close. Most doors either swing on hinges, slide on wheels or, in the case of most garage doors, track into an overhead compartment. From the builders prospective, the hardware used on a door has the greatest impact on the details of framing and installation.

The Pre-hung Advantage
In new construction, most builders prefer to work with pre-hung doors, which are ready-to-install units that arrive at the job site pre-milled and hinged to their frames. Of course, you can dress up any interior or exterior door with today’s broad array of handles and locksets; styles include traditional, contemporary and just about everything in between. Most builders like to use pre-hung units because they save time and may even improve the quality of installation.

Door Installation Details
Studies suggest improperly sealed exterior door or window frames can account for 20 percent of a home’s total heat loss. Before the builder installs an exterior door, the rough opening should be covered carefully with building paper or house wrap. Underneath the sill, the part of the door frame that lies underfoot, an ice and water shield membrane should be installed to provide insurance against rot and termites. The membrane is a rubberized material.
Just before installing the door frame, workers should put a bead or two of caulking underneath the sill to create a watertight bond. Most sills allow for slight up or down adjustment once the door is in place.
After the door or window has been fastened in place, a flashing piece called a drip cap is nailed over the top of the exterior trim. This L-shaped strip of metal keeps wind-blown
water from getting behind the door or window trim.
The process of hanging interior doors follows virtually the same pattern as used for exterior openings, without caulking, house wrap and flashing. Pre-hung doors, whether interior or exterior, arrive hinged so they open in one direction only. Check the swing direction of each installed against your floor plans. Take note of problem doors that swing into hallways or open toward the center of the room. Instead, they should open toward the nearest adjacent wall.