• When building a home or house addition, knowing the sizes of your exterior doors is critical to planning, ordering building materials and constructing the doorways. Buying standard size, ready-made doors is a less expensive choice than having doors made to fit non-standard doorways. Standard size doors are available in a variety of materials, sizes and price ranges. You can purchase your exterior door pre-hung--hinged onto a doorframe--or as a stand-alone unit.
  
  

Entry Doors

• Single entry exterior doors come in three standard widths: 30, 32 and 36 inches. Standard doors are 80 inches tall. Because people typically bring furniture and other wide items through their front or back doors, many choose the 36-inch width to allow as much room as possible. Given enough space, some people choose to use a double door entry unit, setting two standard size doors of the same width side by side, each opening from the center point. When you are planning your construction, you should add 2 inches to the width measurement of the door and 2 inches to the height for the doorway opening. This is called a rough-in measurement. So, for a 36 x 80-inch door, your rough-in opening will be 38 x 82 inches. This applies whether or not you are using a pre-hung door.
  
  

Patio Sliders

• The standard size for sliding patio doors is double the width of a 36-inch entry door, or 72 x 80 inches. If you are simply replacing an old sliding unit, chances are this is the size you will need. Sliding door manufacturers also produce doors in configurations of 3- or 4-units wide--each unit measuring 72 x 80--for a much larger window view. You can purchase pre-made patio doors with heights of seven or eight feet. If you wish to create a wall of windows that includes an exterior doorway, perhaps opening to an attractive flower garden or swimming pool, you may opt for a larger than average patio door.
  
  

French Doors

• French doors are doors nearly completely composed of glass panes or panels framed with wood or another material. You can use French doors singly or in pairs, and as exterior or interior doors. Manufacturers of French doors allow builders a lot of latitude when it comes to dimensions. Panel widths start at 16 inches, and heights start at 60 inches. Different manufacturers make various sized panels. This makes French doors adaptable to narrow exterior wall spaces, such as a master suite balcony. By adding sidelight panels--narrow, door-length windows on either side of the door--to wider sets of French doors, you can open up an entire room to the outdoors.
  
  

Garage Doors

• For many years, the standard size single garage door was 9 feet wide x 7 feet tall, and the standard double garage door was 16 feet wide x 7 feet tall. However, with the advent of the large SUVs in the 1990s, home builders began expanding the measurements of garage door openings, resulting in a new standard height of 8 feet. Many manufacturers produce sectional garage doors which can easily be adapted to different garage doorway sizes by adding or subtracting one or more sections, each of which is just a few inches wide.