Measuring Instructions for Inside Mounting
Measure the depth of the drywall (or frame) at the side of your window. Measure from the outside corner until the point where window obstruction begins. This might not be the actual window. It could be where a lock starts or the end of a window crank. This space must be at least 2 ½" for the plantation shutter to mount inside and work properly. If it is not, you will need to mount your shutters on the outside.
Measure the diagonal of your window. Start all the way in the upper left corner of your window frame and measure to the lower right corner. Then measure from the upper right to the lower left. Compare these two measurements. If they differ by ½" or more, then your window is out of square and you will need to mount your shutters on the wall outside of the window.
Measure your window, both horizontally and vertically, in three places. Measure along each vertical side of the window and then again in the middle. Measure along the inside top and bottom of your window and then another measurement in the middle. If you will only be covering part of the window, make your measurements where the bottom of the shutter will be and where the top of the shutter will be. If your window frame narrows towards the window, measure at the narrowest part.
Measuring Instructions for Outside Mounting
Determine if you will be mounting your shutters on the drywall, outside of your windows, or on the trim around your window.
Measure the window backspace. You will need, typically, at least 5/8-inch clearance for your shutters to work properly. The backspace is the depth from any part of your window that juts out, such as a crank, to where the back of the shutter will be. For mounting on the drywall, outside of your window trim, be sure to consider the depth of the trim. Your mounting frame will need to provide enough depth so that your shutters can be mounted far enough into the room to allow clearance for any obstructions, including the trim and/or a window sill.
Take measurements of the area that will be covered by your shutters. Take three horizontal measurements: at the top, at the bottom and in the middle. Take three vertical measurements: at the left side, at the right side and in the middle.