DIY: Built In Deck Benches With Backs (Steps w/ Videos)

Do you have a deck you just aren’t using enough?

Are you looking for some new seating solutions that won’t be as complicated as moving furniture in and out as the weather changes?

Have you ever thought of building your own benches onto your deck?

There are many people who enjoy the comfort and style of build-in deck benches. These benches can be built with or without backs, but for the most part, choosing an option with a back is the best way to go.

Here are a few benefits of having built in deck benches with backs on your deck:

  • Space-saving seating: You will have plenty of room to walk without devoting it to patio furniture for your deck.
  • Easier to maintain than furniture: You will simply maintain these benches the same way you do your deck.
  • Aesthetically pleasing: This type of style is very modern and looks great in almost any backyard.

Of course, there are a lot of other benefits you may enjoy from this type of setup, and you’re sure to find something all your own to love about your deck benches if you give them a chance. To learn more about how to build deck benches with backs onto your existing deck, check out our quick and easy how-to guide below!


The materials listed below will be required for one individual bench. Multiply these materials as needed depending on how many benches you’re planning to put around your deck. This is a very easy-to-adjust guide that can work with just about any size deck and number of benches, so don’t be afraid to play with it a little to figure out the right options for you.

how to build a bench on an existing deck
  • (9) 2x6’ pieces of lumber per bench
  • (8) 2x4’ pieces of lumber per bench
  • (1) 2 x 4 x 16 piece of lumber
  • Metal deck tie brackets
  • Stainless steel deck screws
  • Circular saw or jigsaw
  • Tape measure
  • Level
  • Power drill and bits
  • Stain and finish
  • Optional: (4) 8x8’ pieces of lumber for legs


Below, we’ve got the steps you need to build benches onto an existing deck, and we’ve also added a few notes at the end for building benches on their own to use on a deck as well. Pick which option is right for you and let’s get started!

  • 1
    To build benches onto an existing deck frame, begin by measuring the perimeter of the deck. This will help you determine how much space you have to work with when it comes to installing your benches and whether or not you have room for any other built-ins, like a small table.
  • For the purposes of this guide, we are going to be building 118-1/2” benches on three sides of the deck. This guide will teach you how to build one bench; repeat the process to make enough benches to go around the deck as you desire.
  • 2
    Use metal brackets to attach 4” x 8’ posts for support every 30” apart per bench.
  • 3
    Cut 2x4 pieces of lumber into 45-degree angles and use metal brackets to attach one on either side of the posts you just attached in the last step.
  • 4
    Cut 2x4 pieces of lumber into four pieces each. Use these cuts to finish the support you are building on each post by attaching the top of the angled lumber to the top of the post.
  • 5
    Use the 2x4x16 piece of lumber to span the distance of the back of the bench. Attach it to the support posts you have just created by drilling a pilot hole first and then using stainless steel screws.
  • 6
    Cut 2x4 pieces of lumber into three pieces, and cut at 27 degrees on the top and 10 degrees on the bottom. Screw these into place at the top of each support beam angle to add more back support on the bench.
  • 7
    Finally, use your stainless steel deck screws to screw the slats of the seat into place first, then the slats for the back of the bench. You should use your 2x6’ pieces for this portion of the project. Don’t forget to attach one slat to the bottom front of the bench for some knee support as well.
  • 8
    If you’re going to build your benches separately from the deck itself, the only real difference is that you’ll need to add legs. Cut legs from 8x8 pieces of lumber and screw them together so that you have a piece of wood acting as a brace to connect two other pieces—think of this as building an H-shape out of three pieces cut from one 8x8 piece of lumber.
  • 9
    Repeat this process and screw the two “H” shapes together to create the front leg. Repeat steps 8 & 9 to make the second leg.
  • 10
    Screw the leg assemblies onto either side of the bench and backrest.
  • 11
    You can then attach this separate bench to your deck as needed for the results you’re looking for.
  • 12
    Stain and finish the wood for best results. You may also paint the wood if you prefer.


Did you find the right steps you need to take to complete the benches of your dreams? When it comes to designing your own DIY deck, there are a lot of excellent options out there that can help you make a big difference in the overall appeal of this type of space. Don’t be afraid to get creative with the guide listed above and try cutting shapes and designs into your deck bench backs if you prefer. You might also be creative when it comes to the size or layout of the benches, and you may end up wanting to install a table on your deck as well. The possibilities are endless, as long as you have the skill to do the woodworking and installing necessary!

how to build a deck bench seat

But what happens when you’re done with the building process? How should you finish a bench like this to make it last as long as possible? In short, it’s best to choose an all-weather stain and varnish type finish for the wood you use on your deck. This is true of the floor of the deck as well as any benches. You will probably want to use the same finish you used on the deck itself to be sure it matches, but the choice is really up to you. You may also want to paint the benches and tables you build, but if you do this, make sure you seal them properly for use in all types of weather. Paint will chip and wear out faster than varnish, so keep this in mind when making your decision.

With the right planning and enough time on your hands, you can complete this fun and challenging DIY project and give yourself and your whole family a new deck experience every time you go outside.


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