White Steel or White Aluminum Quick Frames can be assembled with standard 2 x 4 lumber or galvanized Steel Box Girts as horizontals. Western Products recommends spacing these horizontals approximately 24" to 28" on center. Wood or steel inserts can be placed inside the vertical channel between each horizontal. Inserts should be permanently attached with screws, becoming part of the frame. This is suggested to help prevent damage to the doors in windy conditions. Use self tapping tek screws.