Easy How to Build Your Own DIY Outdoor Sectional Sofa

April 25, 2024

Hi! I'm Nicole

Fearless DIY. Sharing building project tutorials and interior design tips. Let’s build something beautiful together. For more projects, design tips and behind the scenes, follow me @designtobuild.nicole

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Build your own DIY outdoor sectional sofa only using 2×4’s. Design to Build’s plans include easy to follow, step-by-step instructions.

Perusing any furniture store, you’ll find me not only eyeing the furniture, but feeling every nook and cranny of it. In my mind, I’m breaking down exactly how to build it. Searching for the perfect outdoor furniture was no exception.

I just can’t justify spending 2, 3 even $4000, when I know I can build it for a small fraction of the cost.

And so I did. I built the same outdoor sofa that Pottery Barn, West Elm and Crate and Barrel all feature in their stores. Only mine cost less than $200 all said and done. :)


For my outdoor space, I decided on an outdoor sofa and two chairs to match. So, when my daughter-in-law asked me to help her build an outdoor sectional couch, I knew just the one we would build.

Building the sectional set is as easy as building the first outdoor sofa and adding another one to it (minus one arm). 

So basically, we’re going to build this original plans outdoor couch and then build another one, slightly different.

Let’s get to the building plans!

How to Build Your Own DIY Outdoor Sectional Sofa

(Instructions are based on an outdoor sectional build with the following measurements: 

  • 2-arm sofa: 25″ tall; 72″ long; 25″ wide 
  • 1-arm sofa: 25″ tall; 70 1/2″ long; 25″ wide

If building a different size, be sure to adjust the overall dimensions accordingly. 

Sofa is built to fit 22″ x 24″ cushions. You’ll need 6 seat cushions and 6 back supports for this build. 

I purchased these cushions from Target.

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Wood Needed for DIY Outdoor Sectional Sofa:

24-2x4x8 pine boards

Supply List Needed:

Tools Needed:

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NOTE: If you’ve never used a Kreg Jig, here’s a great tutorial.   If you don’t have one, I highly recommend buying one. You will use it all the time in the DIY realm! And it makes builds so much easier! 

Step One: (OPTIONAL) Rip your boards

This step is completely optional. I like to get rid of the manufactured edge on all of my 2x’s before starting any project. This is very easy, but does require a table saw. I’ll share the width I’m ripping them down to for this project and then explain how I do this…

Since this project consists solely of 2×4’s we’ll rip all of them to 3″.

Now for How I Do This: (Here’s a great post on how I give my boards this finished look)

  • I want all of my boards to be 3″ wide. (Originally a 2×4 is 3 1/2″ wide).
  • I simply set my table saw for 3 1/4″ and rip one side of my 2×4.
  • Then I set my table saw to 3″, flip my board over and rip that side of my board.
  • Now I have a 3″ board with straight edges on both sides.

This extra step gets rid of that manufactured curved edge and achieves a straight edge look.

SIDENOTE: I found it easiest to sand each board as I went with this project…rather than sanding it all at the end. 

Here’s a great post all about how to get a smooth finish on your DIY furniture. 

Step Two: Build the armrests (side frames)

For this step, we’re going to build 3 full size armrests.

Cut six 2×4’s to 22″

Cut six 2×4’s to 25″

Drill 1 1/2″ pocket holes into each end of the 22″ boards.

Attach together to make a square using 2 1/2″ pocket hole screws. See picture below for more clarity….

Three 2x4's jigged together to make a U shape

NOTE: As you add each board, be sure to check for square. You’ll want to ensure that every corner is a 90 degree angle. You can do this by using a square (which is actually triangle shaped). Here’s a picture of a square…

Picture of a metal square for woodworking.

I like to use these nifty gadgets when checking for square. They’re less than $10 over on Amazon. Here’s the link, if you want to grab a set.

Picture of red squares for woodworking.

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Follow these same steps for each armrest.

Your armrests should now look like this and you should have three….

Four 2x4's jigged together for a DIY outdoor sectional sofa armrest.

​Finish the armrests: 

Before moving onto the next step, we need to add one more board to the armrests:

  • Measure up from the bottom of the square 10″ and mark both sides.
  • Cut a 2×4 to fit between the two 22″ boards.
  • Drill 1 1/2″ pocket holes on both ends of your board “made to fit” and attach between the two 22″ boards using 2 1/2″ pocket hole screws.
  • The top of your board, “made to fit,” should line up with the mark you made on both sides….

Your armrest is now finished and should look like this…

Armrest complete for outdoor sofa

Repeat for the other armrests and you should now have three armrests that look like this.

Note: The armrests you see in the background of the picture below are for the outdoor chairs I was also building at this time. (Here are the plans, if you want to check those out) 

Two side armrests made of 2x4's for one of two outdoor sectional sofa.

Step Three: Build the partial armrest (partial side frame)

For this step, we are going to build a partial armrest.

Cut list:

  • One 2×4 to 25″ …..Drill 1 1/2″ pocket holes on one end. (A in picture below)
  • One 2×4 to 22″  (B in picture below)
  • One 2×4 to 25″   (C in picture below)
  • One 2×4 to 8 1/2″….Drill 1 1/2″ pocket holes on both ends.   (D in picture below)


  • Using 2 1/2″ pocket hole screws, attach the 25″ board to one end of the other 25″ board.  (A is attached to C in picture below)
  • Using 2 1/2″ pocket hole screws, attach the 8 1/2″ board to the other end of the 25″ board (the 25″ board without pocket holes). (D is attached to C in picture below)
  • Using 2 1/2″ wood screws, attach the 22″ board between the 8 1/2″ board and the 25″ board. The top of the 22″ board should be flush with the top of the 8 1/2″ board. (B is attached between A and D)

See the diagram below for more clarification….

Outdoor sectional sofa diagram.

​You should now have 3 full size armrests and one partial armrest.

Step Four: Build the seat base for the DIY outdoor sectional sofa

Cut four 2×4’s at 66″

Drill pocket holes on both ends of all 4 boards.

Attach to the front and back of 2 full armrests, using 2 1/2″ pocket screws. You will want them flush with the top of the “made to fit” 2×4 we added to the armrests. See picture below for more clarity….

Diagram of placement for boards for the outdoor sofa build

Here’s another look at the 66″ board attached to the armrests. As you can see in this picture, I used scrap wood to hold my board up when attaching. This made working against gravity a little easier…

2x4 propped up using boards to jig into two armrests

We are now left with one full armrest and one partial armrest. Attach the 2 remaining 66″ boards to these armrests, using 2 1/2″ pocket hole screws.

Once again, you will want them flush with the top of the “made to fit” 2×4 we added to the armrests.

See the picture below for more clarity…

DIY outdoor sectional sofa frame made of 2x4's.

You should now have two sofa frames built.

Add the seat slats:

Cut ten 2×4’s to fit between the armrests. (Cut to fit, but they’ll be approximately 66″). These will be your seat supports…

2x4's cut to fit between armrests to form seat for outdoor sofa

​Drill 1 1/2″ pocket holes on each end of the seat supports…

A girl making pocket holes in a long 2x4 pinewood board

Attach 5 seat supports to each sofa frame, using 2 1/2″ pocket hole screws. You’ll attach each seat slat to the side frames. Here’s a look at what one section of your outdoor sofa should now look like….

Notice how the top of the seat supports are flush with the top of the “made to fit” 2×4 added to the armrests.

2x4's attached for seat of outdoor sofa

Step Five: Build the back rest

Cut two 2×4’s at 66″

Drill 1 1/2″ pocket holes on each end. Attach, using 2 1/2″ p.h. screws, in between top of armrests (making it flush with the top of the armrests). Do this for both sofa sections…

Diagram for outdoor sofa build to point out placement of 2x4's

Cut four more 2×4’s at 66″

Evenly space 2 of the back slats between the top back board and the seat back board. Attach using 2 1/2″ p.h. screws. Do this for both sofa sections…

Diagram for outdoor sofa build to point out placement of 2x4's

​Pushed together your outdoor DIY sectional should now look like this…

Sectional sofa in a garage space.

You’ll notice in the picture below, the back slats have not been added. Your sectional should look a little different than the picture above, with the back slats added.

Step Six: Finishing touches for the DIY outdoor sectional sofa

If you haven’t sanded as you built, sand the entire project now. Starting with a 60-grit and finishing with a 220-grit for a smooth finish.

Choose your color stain or paint and apply to the entire piece.

I chose a dark color for my outdoor sofa. Here’s a look at my set up on my outdoor patio…

Pergola space with outdoor furniture and planters

I think my daugther-in-law is going with a lighter stain.

Be sure to apply an outdoor sealant over the entire piece to protect it from the elements. I chose an outdoor poly for my finished project.

Choosing The Right Outdoor Cushions

My go-to for outdoor cushions is Target. They have a good selection of neutral colors available. As I mentioned before, you’ll need 22″x24″ cushions for your outdoor sofa. No need to buy a specific corner cushion. All that is needed are six 22″x24″ seat cushions. Here’s the link to the one’s from Target that I have bought in the past.

Sectional sofa in a garage space.

If you live in an area that has colder months throughout the year, these outdoor covers work great!  We use them to protect all of our outdoor furniture.

I hope you found these detailed step-by-step directions for this beautiful DIY outdoor sectional sofa to be helpful. Are you ready to build your own outdoor sectional sofa? As always, if you have any questions, please don’t hesitate to ask.

I love helping you turn these build plans into a beautiful furniture piece.

Let’s go beyond the design to build something beautiful together!

Until next week,

Happy Building, Friend!!

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Hop over to Instagram to see all of the D2B behind the scenes. What am I working on now?….come check it out!

More Great Outdoor Projects:

Choosing The Right Outdoor Patio Furniture to Fit Your Style

Ideas for How to Create a Comfortable Outdoor Living Space

Revealing our Outdoor Summer Hangout Living Space


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