Outdoor Built-in Bench for Our Deck

3 Materials
4 Hours

A wood working tutorial on how to build a corner built-in outdoor bench. This corner has always been a little bit of a “dead man’s land” tucked all the way back behind my home. I had considered a little seating area and even thought about building a tall pub table here but it didn’t feel like that was utilizing the space as well as it could be. A friend of mine has an outdoor bench running literally around her entire deck in place of a railing and the amount of seating offered is just amazing.

outdoor built in bench for our deck

However, I have way more deck then she does and certainly don’t need that much bench! But this corner spoke to me as being the perfect place for an L-shaped outdoor bench!

outdoor built in bench for our deck

I built my smaller bench first by building a rectangle out of 2x4s and adding legs where they were needed. I didn’t see any reason to add legs to my benches where the deck already had posts so I kept that in mind as I was building.

outdoor built in bench for our deck

I went on to build the much longer bench (over 10 feet!) also with legs only where they were needed. Because of the distance I chose to cut my 8 foot 2x4s so the “seem” would land on one of the posts instead of requiring to add two legs in a weird spot. I flipped my benches “right-side-up” then attached them to each other before screwing them to the main posts.

outdoor built in bench for our deck

You can kinda see in the pictures that one of the back corner 4×4 posts really curved out over the last 2 years… It has annoyed Joe and I like crazy so we took this opportunity to right it. Joe pushed on the darned thing as hard as he could when I screwed the benches to the posts and viola – not perfect but MUCH better! (You can see one of my  little jar solar lights back there, not as pretty as when I first made them (the glue gave when it hit over 100 degrees this July!) but this one and all of the others still work great!)

Next I just needed to cut around eight million 24 inch boards for the seats… I set my miter saw up outside for this (thank you Joe for the awesome Xmas present of a miter saw stand on wheels!!) so I didn’t have to measure every board! Then I just stood there and cut and cut and cut. I used the deck as best I could for a saw horse but in the end it was kind of a pain in the butt because green treated wood is so heavy.

outdoor built in bench for our deck

(I used green treated wood on this project which is made to be outdoors – it is more expensive then regular pine and considered very toxic. We live in northern MN and I know folks with cedar decks who watched them degrade within only 5 years of having put them in so, honestly, there was no choice but to use green treated wood on this project. Green treated anything requires up to a year to fully out gas and dry out which is why I built them in the late summer to give them the entire fall, winter and next spring to sit and do their thing.)

outdoor built in bench for our deck

With the seat complete I moved on to the back of the bench. I wanted to create a little bit of a slant so I screwed a deck board all the way around the back of the bench pressed tight against the deck posts – with it laying down flat it was 5 1/2″ from the back of the bench to the front of the board. Then I duplicated that board where the top of the back rest would land, screwing it to the deck posts all the way around above the benches. Then it was just a case of putting another two million 24″ boards on, lining them up with the bottom seat boards.

outdoor built in bench for our deck

(Because the slant was not very severe I didn’t feel the need to miter any of them.) SO, pretty much I just stood there and cut 24″ boards for most of the day…

outdoor built in bench for our deck

With the majority of the outdoor bench complete I just needed to figure out what I wanted to do in the corner. Using a scrap piece of wood I created a support across the top of the corner and across the base. This gave me a place to put one more board. I considered doing something a lot more complicated in the corner but I didn’t hate this both in looks and in functionality… 

outdoor built in bench for our deck

UPDATE: it has become my favorite spot to sit and read actually!

outdoor built in bench for our deck

I also went ahead and screwed all of the 2×4 legs down to the deck.  With the bench complete this no-man’s land has now become my favorite outdoor escape.

outdoor built in bench for our deck

Eventually I plan on covering the back bottom of the bench (on the outside of the deck) with lattice like I did along the bottom.

Suggested materials:

  • 1x6 green treated deck boards  (local lumber yard)
  • 2x4 green treated  (local lumber yard)
  • 3" deck screws  (local lumber yard)

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Want more details about this and other DIY projects? Check out my blog post!


Have a question about this project?

1 question
  • Allison Newby
    on Oct 28, 2017

    Very good job....but is it really okay to not put a 2x4 post where you used the deck post and a square piece of 2x4 attached with a 3"screw. Overtime won't that part of the seat cave in or be the first to break bc it's compromised and isn't apart of the whole but added to another part with a part of board? I just worry about the future of the seat and it's stability as a whole? If a carpenter says this is okay then I'm sold but I don't know. It just seems iffy....I'm sorry. It looks wonderful but im just a worry wart I guess. Please don't mistake this as being ugly. Thanks. Sincerely, Allison Newby
    • GrandmasHouseDIY
      on Oct 30, 2017

      With the brace of the main bench running entirely around the back with several screws into the main posts as well as the top seat brace running along the back as well with also many screws in it I felt confident when I built this that it would be here for many years to come :) Thanks for checking it out and commenting Allison!

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