The simplistic design and square shape of a pergola makes it a simple project to build for the average do it yourselfer. If you have access to average wood working tools, have a deck that is raised high enough so that you can get beneath it, then this project may be one you wish to consider. The premise behind this project is to cut holes in the decking and place the upright beams through them. They can then be fastened to the joist beneath. Add some simple wooden edging, and you have a custom made pergola. Here, we discuss this project, materials needed, and construction tips.
Setting your Design
This design assumes you have a raised deck, and enough area to get the height needed. You should plan on the upright standards being 9 feet, as we will use 10 foot 4″ X 4″ cedar posts for construction. The pergola will be 8′ square with 4×4 cedar posts, doubled 2×8 beams, and use battens for mounting a sunshade. The plan is based on one of the many blueprints available on the internet.
You first should check with local authorities to determine if there are any building codes you need to follow. You might also need a permit.
Let’s build It
To help simplify the process, I have added some 3D illustrations, which will be referenced throughout the guidelines.
Begin by laying out your 8′ by 8′ area. This will be measured from outside of each post to outside of adjacent post, and will be measured from inside edge of the joist. It is very important to “measure twice, cut once” here to avoid damage to the deck. We are assuming that the deck has 2×8 joists 16″ on center.
Making the Measurements
1. Determine the inside edge of the joist as a starting point, and mark. 2. Measure 8′ along this joist, making another mark. 3. Snap a chalk line between these 2 points. 4. Drive a 6D nail halfway in at the mark, and use as a measuring point for other legs of 8′ square. See illustration #1. A highly accurate method of making these measurements can be found on the web.
Making The Cuts
1. From your starting point, use a short length of 4 X 4 to lay out post hole on deck. 2. Cut 4 X 4 hole in decking. See illustration #2. 3. With the aid of a helper, stand the post on end, and carefully place in 4 X 4 hole. 4. Drill 2 1/2″ offsets holes through the post and joist. 5. Secure the post with the 6″ carriage bolts. See illustration #3. The offset helps maintain structural integrity. 6. Repeat for remaining 3 posts. 7. Measure each post 8.5 feet from deck, and cut each at this mark.