DIY: This Is How To Build A Deck Bench Seat With Back (Steps w/ Videos)

Do you have a deck that needs some seating solutions?

Are you looking for a fun and challenging DIY project you can complete on your own or with help?

Have you ever considered building deck benches?

In this article, we’ll show you how to build a built-in deck bench with a back that will be part of your deck structure in a permanent way. You can complete this project whether you are a beginner or a pro, but just make sure you take your time and understand all the steps first either way.

But why would you want to do this? Why is it a good idea to learn how to build a deck bench seat with back?

  • A seat like this can keep you from having to buy, clean, or deal with patio furniture in the future.
  • This type of project can be a challenging but exciting group activity.
  • A bench like this can add a lot of value to your deck.

So what is the biggest downside to building this type of project yourself? It’s quite expensive to buy the lumber and materials needed, and it can take some time to complete this job. However, if you have the funds and time to devote to it, you can have something truly beautiful when you’re finished.

Now, let’s get started building right away!


ow to build a deck bench with backrest
  • 9 pieces of 2 x 6 x 120 lumber
  • 2 pieces of 2x4 lumber
  • 4 pieces of 4x4x8 lumber
  • 8 pieces of 2x4 lumber cut to 45 degrees on one end
  • 8 pieces of 2x4x20-7/8” lumber
  • 1 piece of 2x4x120 lumber
  • 4 pieces of 2x4x27-1/2” lumber
  • Deck tie brackets
  • Power drill and deck screws
  • Paint, stain, or finish as desired


  • 1
    Begin by measuring the perimeter of your existing deck. If you are building the benches at the same time as the deck, measure the perimeter of the space where your deck is going to go—but keep in mind that you won’t be able to start on the chairs until the deck is completed.
  • 2
    For the purposes of this guide, we will be discussing how to build one bench with a back. Keep in mind that the number of materials you need will change depending on how many benches you plan to build.
  • Also keep in mind that you may need to adjust the measurements of the materials listed above if you plan to build smaller or larger benches. This guide is a great starting point, but it can be easily modified.
  • 3
    Measure the length of space your bench will be taking up. For our purposes, we will be working with a measurement of 118-1/2” for the length of the seat.
  • 4
    For a bench of this length, you will need four support posts in the back. Position each of four 4x4x8 lumber pieces 30” apart from each other and attach to the deck using deck screws and deck tie brackets.
  • 5
    Next, position the 45-degree angled lumber pieces so that they sit at an angle on either side of the four support posts—two per post. Attach with deck screws.
  • 6
    Using deck screws, attach your 2x4x20-7/8” pieces to the tops of either side of the support posts so that they sit on the angled top ends of the side beams. Again, you will need two per post, or one on other side.
  • 7
    Use your 2x4x120” piece of lumber and attach it with deck screws and deck tie brackets across the length of the back of the bench you have just constructed.
  • 8
    Attach each of four 2x4x27-1/2” pieces of lumber to the left of each of the support beams you have created. You need one back support beam for each post support.
  • 9
    Now it’s time to start attaching the slats for your bench to the framework structure you’ve built. Position one slat in the front of the bench to provide some support for the back of your legs, and use the others to build the set and back. Attach the slats flush with each other using deck screws for the seat.
  • 10
    Attach the slats with some space between each one for the back. Use deck screws here as well.
  • 11
    From here, you can stain or finish the seat as you wish, or you can paint them. Don’t be afraid to get creative and make your bench truly yours!


Were you able to learn everything you need to know about building your own deck bench with a back? There are many different ways to go about this project, and this is only one of the variations you might be interested in. Just make sure that, no matter which method you choose to go with, you pick something that you can easily adjust to fit your existing deck size as well as the number of benches you want to have around the structure.

Picking a guide that is easy to adjust is crucial when you’re working with any measurements that are even slightly different from the ones listed here. When completing any woodworking project, keeping your measurements accurate is very important, and this is no exception! But with a little adjustment, you should be able to make this guide or any of the others we have linked here work well for you and your needs.

Of course, building is just the first step. Making your benches your own is the next fun part! It’s always a good idea to finish, stain, or paint the wood you use on a project like this in order to keep it from weathering badly. But you can also do a lot more to make your benches look more uniquely you, especially if you have a theme or a type of decor you’re working with in your yard.

Here are a few easy ways to decorate this type of seat:

  • Use throw pillows or outdoor blankets. You can easily find all sorts of cushions and similar products that can help you make your seats more comfortable as well as more fashionable. Try out a few different combinations until you find just what you’re looking for.
  • Let the kids help paint. If you have little ones in your family, use outdoor kid-friendly paint and let them get creative on your benches. They can leave handprints or draw whatever they might want to decorate your deck for a long time to come.
  • Don’t forget lighting and plants! Although these are more like deck decor than specifically items for your benches, it’s still a good idea to spruce up your outdoor space all the way around. Combine this with other ideas and you’ll be well on your way to a more decorative and comfortable outdoor space in no time.

Good luck with your new deck bench project!


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