How to build a DIY outdoor sectional couch

A main part of our deck building project was to increase our outdoor living space, and a great way to do that is with a DIY outdoor sectional. We wanted comfy seating outside where we could sit in the shade and watch the kids play in the pool. A place to enjoy our morning coffee, or maybe to have an afternoon nap. 

Catch up on our deck building project:

• 1: How to design a deck
• 2: How to install deck footings and sonotubes
• 3: How to install deck posts, beams and joists
• 4: How to install deck boards
• 5: How to build deck railings and stairs

For our outdoor sectional I used reclaimed fir wood. I was given some 150 year old lumber that was reclaimed from an old school house (I have some of the best friends that think of me when they come across some cool wood).

However, I have adjusted these plans to work perfectly with 2″ by 6″ lumber, because I realize not everyone has access to reclaimed lumber.

Tools and Supplies

These materials are for one 6 foot long couch. If you want to make two couches to make an L-shaped sectional, get double the material. 

• For one 6′ couch: 4 of 10 foot long 2″ x 6″
• For an arm rest: 1 of 10 foot long 2″ x 6″
• 4 deck spindles
• ~13 feet of deck boards
• 2″ deck screws
• mitre saw
• palm sander and paper
• pocket hole jig
• clamp
• cordless drill
• tape measure
• square
• wood glue

Prepare the wood

If you’re using pressure treated lumber you can skip this step. For me, I used reclaimed lumber so had to do a bit of prep work. First, I removed all the nails and screws that were in the wood. Then I quickly sanded all the pieces using my palm sander and 80 grit paper.

Cut the lumber

These plans are for a 6′ long couch that is 32″ high with a seat height of 15″. To make it a sectional, simply make two of these couches.

Use a miter saw to cut all your pieces according to the picture below. The three pieces for the back of the couch are cut on a 45 degree angle, and the top of the back piece is 6′ long at the longest point. 

Sand the corners of the cut ends

To really make it look like a professional job, just lightly sand the corners of all your cut ends; sand all the cuts except for your 45 degree corners.

Drill the pocket holes

Using a cordless drill and a pocket hole jig and drill bit, put four holes at each joint, two holes on each side. You’re technically supposed to use a clamp when you use the pocket hole jig, but I am too lazy for that.

Glue it and screw it

I started by putting together the back of the outdoor sectional. I put a bead of wood glue on the mitered corners, and then used deck screws to screw the corners together.

Glue and screw the sides and front

The next steps are fairly simple. Just glue and screw the side pieces to the front legs, and then attach them to the back of the couch. The last piece I did was the front, and I screwed this piece into the two side legs. You’ll want to use a square to make sure all your joints are at a 90 degree angle. 

Make the seat

To hold up the seat I cut down some pressure treated spindles and screwed them to the front and back of the seat area. I screwed them about an inch below the top of the couch, so the deck boards would be flush with the top.

For the seat, I just cut a bunch of deck boards down to about 22.5″ to fit snugly inside.

How to make a sidearm

If you are going to make an L-shaped sectional, one of your couches will need a sidearm. The measurements for the side arm are below, and you just do the same process as the couch to make the sidearm. Once it’s completed, screw the arm into the side of your couch.

DIY outdoor sectional

The last step is to move the couches into position, and get some cushions. I bought 24″ by 24″ seat cushions with a separate high back cushion. The cushions I bought are reversible so I can either go with a solid color, or switch it up to the pattern if I’m feeling adventurous. 

NEXT WEEK…

Next week is the final deck reveal, and a summary of the entire deck building process from start to finish. If you have any questions about this DIY outdoor sectional building project, please feel free to drop a comment below.

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