Order Instructions: How to Measure and Order Length is the distance the material will run. Width is the space between the joists. 1. Standard-width openings A Standard Width Opening (SWO) measures 16 inches from the center of one joist to the center of the next. Enter: Total Length of All Standard Width Openings and openings narrower than standard width: Add together the lengths of all SWOs in this group. For example, four 12-foot openings equal 48 linear feet. Number of Standard Width Openings: Enter the total number of SWOs in the group. In the example above, enter 4. 2. Openings wider than standard A Non-Standard Width Opening (NSWO) is any opening wider than the standard 16-inch, center-to-center spacing. Enter: Total Length of All Non-Standard Width Openings: Add together the lengths of all NSWOs in this group. Number of Openings Wider Than Standard: Enter the total number of wider openings. Size of Openings Wider Than Standard: Measure the width of each opening in inches, from the outside edge of one joist to the outside edge of the next joist. Enter the width of each wider opening. 3. Add the order to your cart Save this group to your cart. If you have multiple wider than standard openings, repeat the process and add them as a separate item. 4. Check for obstructions Make sure every joist opening is clear of blocking, pipes, wiring, or other obstructions that could interfere with installation. Have questions about your deck? Attach a clear photo of the underside of your deck using the form below. We’ll review it and let you know whether your deck is suitable for the Underdeck Umbrella system.
