Surround Measurement Instructions
The Finish Window Surround Width Measurement is the inside of the extension jam to the inside of the opposing extension jam. You must determine where the inside of the surround will meet the window. This is called the reveal. Usually a 1/4″ reveal is exposed around the inside of the window. It can be more or less. The reveal is to be determined by the customer. Determine where intersecting reveals meet in all four corners. Mark corners and measure top and bottom. The two measurements should be equal. Refer to picture. Take into consideration handles to open and close window for clearance.
Extension Jam Measurement Instructions
The extension jam is the material which meets the window itself and comes out to the plane of the wall surface. Determine the extension jam width by placing a measuring tape against the edge of the window where the surround will meet the window and read the distance from the window to the plane of the wall. Use a straight edge to assist in the measuring. Measure all four corners and compromise on one common measurement.