How to Understand Wood Window Sizes

When you are building a new home or office you may receive the architectural plans of how it is going to look when done. All the doors, windows, rooms and the entire layout will be on those drawings. When you see the window sizes you may be a bit surprised and not understand any of it. A little insider info will help you in this area.

1. Look at your architectural drawings. Find the location of one of your windows and read the dimensions. They may say something like “2646” and you have no clue to what that means. In this case it represents a window whose size is 2-feet 6-inches wide and 4-feet 6-inches tall. All you have to keep in mind is that the first digit is feet and the second digit is the inches of width. The third digit is feet and the fourth is the inches in the height of the window.


2. Keep in mind that the “2646” in this example is the actual window dimensions. There may also be a “RO” listed on the plans that stands for “rough opening”. This will be the actual hole in the side of the house or business where that window will be placed. It will be normally from 1 to 1 ½-inches larger than the windows actual size. That will permit the window installer to have room for making adjustments and get the window level within the opening.


3. Look for another term that may be on your architectural drawing relating to the windows. That would be the word “egress." Egress normally means exit.  The plans will state the window is a non-egress or egress window. This is an official term that in the building codes states the minimum size a window has to be in order for a person to escape through the window should an emergency occur. That code will vary from place to place depending on local laws.


4. Check to see if there is one last term used in drawings of homes and businesses pertinent to windows are known as window grids or “lites." If the window is divided into any kind of sections it will be listed on the drawings as well. An example would be “2 X 4 SDL." That would mean that the window is divided into two vertical columns and four horizontal columns. Simply put it states the window has eight separate panes in the window.