What a Good Carpenter Knows

There are a lot of options and choices to make when selecting a new window or set of windows for your home. However, there are three things a window must always be. A good carpenter knows that a window must always be level, plumb and square.


Level- The carpenter’s definition of level is a perfectly horizontal line. That means that when a carpenter puts a window in an opening the horizontal sides of the window must be flat and even. There must not be any slopes or bumps. The horizontal sides of the window must be parallel to the ground. A tool that can be used to check this is -you guessed it! - a level.

Plumb- The carpenter’s definition of plumb is a perfectly vertical line. That means that when a window is placed in an opening the vertical sides must create a perfect vertical line. They must be perpendicular to the ground. There are certain tools a carpenter can use to check this. A plumb bob is one example.

If a window is not plumb it can be aesthetically unpleasing. It can also cause the window to sag in the corners, and fall closed after opening. In the case of a side to side sliding window the window may not operate correctly.

Square- The carpenter’s definition of a square window is one that is both perfectly level and plumb. If a window is level and plumb the corners will create a 90-degree angle. A carpenter’s square can be used to check the angles of a window.


True- If a good carpenter installs the window to be level, plumb and square it will be true. When a window is true it is square on both the plumb (vertical) and level (horizontal) axis. This will keep the window working properly for a long time.