We just had a new composite deck installed and wanted a pergola to cover a portion of it. My husband, Craig, designed this one and set to work with just the plans in his head. It is cantilevered, thus supported by two legs on the outside of the deck, in order to be more sturdy and stable than one attached to the top of the deck. It is attached to the side of the deck as shown in my blog post. No kits were available for this type of deck, so he purchased the materials from a nearby lumber yard.
Cantilevered Pergola -- DIY Designed and Built
1 Material
$400
1 Week
Medium
Read about our self-designed and built cantilevered pergola built for around $400.
Cantilevered pergola over part of our deck
When the deck was being built, we had the contractor attach two 24-inch all-thread bolts into the deck’s foundation so he could use these to anchor the two legs of the pergola. In the photo above, you see one of those bolts sticking out from the side of the deck (bolt is just above the far-left end of the lattice in the lower portion of the photo above…just to the right of the center).
The second foundation all-thread bolt is shown above between the little strip of lattice and the steps on the right side of photo. Craig would use these two bolts to attach and stabilize the main support legs of the pergola.
He’d pre-drilled the hole in the lower portion of these support legs and slid them onto the large all-thread bolts that extended from the deck. He’d previously dug-in two 6-inch post footers directly underneath the all-thread bolts. The support legs and first braces go up. Craig had pre-drilled most of the holes for the carriage bolts and lag screws.
Additional supports are added to serve as counter-weights since the rafters extend 7' over the deck without supports on the other end.
Notches were cut on both ends of the cross-pieces. He used carriage bolts and lag screws to connect all of the supports.
Once the seven rafters were in place, Craig measured the distance between them and moved them as necessary to even out the spaces at roughly 16″ on center. He toe-nailed a 3″ exterior wood screw into each of the seven rafters on the outside notches to secure them.
Later he added 10 8′ 2″ x 2″s to provide a little extra shade and additional support for vines to cling to in the future. (see last photo below)
He spent $400 on materials. Kits for traditional pergolas begin around $800.
See additional photos in the Comment area.
Materials List Item Quantity 6” x 6” x 10′ pressure treated post 2 4” x 6” x 10′ pressure treated post 3 2” x 8” x 10′ pressure treated board 4 2” x 6” x 16′ pressure treated board * 7 1/2” x 10” carriage bolt 20 1/2” nut and washer for carriage bolt 20 1/2” x 8” lag screw 20 1/2” x 6” lag screw 4 6” post foot 2 Concrete for 2 post footings Total with delivery ~ $400** * Note: number of 2” x 6” x 16′ boards may vary from 7 – 10 depending on desired spacing between rafters. We used just 7 for rafters 16” on center. My husband pre-drilled holes in the boards and laid them on the garage floor in the manner in which they would be put together. He could also mark the angles for his cuts for the smaller support pieces with everything on the ground. I hope this helps anyone who might be interested in building this pergola.
We added commercial globe string lights from Save-on-Crafts so we can enjoy the deck at night.
Craig later stained the pergola and planted non-invasive American wisteria in pots next to each post. Here you see it in 2018 (pergola built in 2015) after we redesigned the screen porch, had the house re-sided and cut down the giant cedars that were blocking the view of the southern Virginia mountains.
Suggested materials:
- See materials list in the Comments section along with additional photos
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3 of 37 comments
Sue P.on Aug 21, 2018Looks great! You did a good job! I think ours is a bit more slanted upward on the front end, otherwise it looks just about the same. Here's how ours looks now, three years later and still standing without any problems. We stained it and planted wisteria in pots next to each post. By being in pots, we can control it and not let it take over the back yard.
Mike Collinson Sep 3, 2018Sue, is it known if this would support a swining bench. If not is ther settle changes to make it work or would that become some knda nightmare. I do plan on using 3 foot holes with concrete. Thanx. Mike
- Sue P.on Sep 3, 2018
If the swing is attached to the large cross beam that runs between the two large posts, it should be supported. Don't hang it anywhere else.
Have a question about this project?
Thinking about building something similar but with a steel roof. I was going to use 3-6x6 posts but I'm worried about how to set them in. How were the posts set in your project and how sturdy is it. Where i am. i'll also need to worry about frost and snow load.
Your questions are well thought out.
This cantilever’s structure is probably not going to hold snow nor wind load.
Your city may have a prototypical set of plans for a Patio Cover, that they’ve approved. Ask them if they do.
If not, please read my comment about the “free” engineering services that essentially come with the Plans Check Portion of Building Permits.
I am very inspired by this! My only issue is that i would be building it on concrete and cant dig down 3 ft to secure the posts. Any suggestions?
There are brackets made specifically for attaching a wooden structure to concrete. However, we don't have any experience with using them so can't make any recommendations. You might talk to someone at a building materials store for more information and suggestions.
Love the design Sue and is just what I need here in AZ! Does this structure rely on support from the deck (connected) or is it free standing? Thank you.
Thank You!!