Trimming the Sides of the Window

With the Mitered method, you simply measure the side of the window from the top edge of the trim to the bottom and add the width of the J (the visible part). On the bottom end of the J you´ll cut a miter, like in this picture. Then make a notch in the other end like this. This will be used to help shed water with the top piece. Getting this cut right will just take a little practice.

Don´t forget that one of the benefits of siding your house is that you can fix things that might not have been done right the first time, or are worn out. This would include flashing windows. The entire process of properly flashing windows is covered in our Windows Section, but I do want to mention it here. Flashing your windows prevents wind and water from getting in. It also helps shed water in the proper fashion, so be sure to check out that section before installing the J-Channel.>

Existing Wood Trim