Wood & Concrete Outdoor Bench

This wood and concrete outdoor bench features a really sturdy base, a modern, minimalist design and it's pretty cheap to make. The concept is pretty simple: you build a mold using plywood which you cast concrete in, with J-bolts attached. Then you drill through some 4x4 wood and attach the wood to the concrete bases. Once you've made the molds you can reuse them and create more bases to make additional benches!

There's a video that goes over all the steps in detail, so make sure to watch that for a better perspective of the process.

Step 1: Making the Mold

The first step is creating the molds. I used 1/2 inch plywood and these are the cuts that you need per mold (you'll need two molds per bench, or you can reuse the same mold twice, however it's easier with two molds.)

Cut list needed per mold :

2 @ A - 14 x 17 1/2 inches (35.5 x 44.5 cm)

4 @ B - 3 x 9 inches (7.5 x 23 cm)

2 @ C - 9 x 9 inches (22.9 x 22.9 cm)

1 @ D - 17 1/2 x 8 inches (44.5 x 20 cm)

Step 2: Cutting the Profile

Cut A needs to be trimmed down a bit to achieve the right profile. I used a bandsaw, however you could also use a jigsaw to accomplish this cut.

Step 3: Assembling the Mold

Once I had all my cuts, I assembled the mold using screws. To make sure the concrete didn't get stuck in the corners, I decided to use silicon caulk.

Step 4: Positioning the Molds

Since the concrete bases will be so heavy once made (about 120 lbs each), I wanted to pour the concrete into the molds, close to where I ultimately want the bench. I placed a 4x4 on top of the two molds with a level on top, just to make sure they were sitting correctly on the ground.

Step 5: J-Bolts

You will need three j-bolts for each mold (one j-bolt for each 4x4 piece of wood). After positioning the 4x4 on top of the mold, I marked out how far down each j-bolt should sink into the concrete. You want to have enough space so you can screw on the washer and bolt.

Step 6: Concrete

I used 1 1/2 80lbs bag of fast setting concrete for each mold. Once the mixed concrete was poured into the mold, I first tapped it all around with a rubber mallet to reduce the amount of bubbles. Next, I marked out where the center of each 4x4 will go and then I placed each j bolt at that position. I tried to be really careful to make sure the bolts went in just right, and that they were nice and square.

Step 7: Removing the Molds

I waited about 6 hours before removing the molds on the sides, and then I waited overnight to remove the bottom piece. Everything went very smoothly, and the concrete didn't get stuck or anything.

Step 8: Cutting the Wood

At this point I positioned where I ultimately want the bases, and measured how long the wood needs to be. Overall, I decided to make my bench about 5 1/2 feet, however this would be easy to adjust depending on what size space you have to work with. I then cut three 4x4 boards to size, accounting for about 1 1/2 inch overhang on each side of the base.

Step 9: Drilling

Next I marked out where the J-bolt will go through on each 4x4. I began with drilling a large, shallow hole with a 1 1/4 inch Forstner bit on each side of the board (this is so the washer will fit). Next I completed the cut with a 5/8 bit all the way through.

Step 10: Attaching the Wood

Now it was time to attach the boards to the j-bolts. I used a rubber mallet to get the wood in position. If you attached the j-bolts right, and drilled the holes square, it all should go smoothly. If not, you can always enlarge the holes slightly to create more wiggle room. Once the j-bolts were through the wood, I secured them in place with a washer and a bolt. I used a reciprocating saw to cut off the part of the bolt sticking up.

Step 11: Grinding the Metal

To make sure the bolts are absolutely smooth, I used a grinder to remove any bits sticking up at all. Later on I'm planning on filling all the voids with epoxy so that water won't be able to collect in this space.

Step 12: Sanding and Finishing

At this point I sanded all the wood, and finished the bench with some water based Spar Urethane to add some protection.

Step 13: Conclusion - Watch the Video

For a much better perspective, make sure to watch the video that goes over all the steps in more detail.

Comments

[Jaysfitmom]

Great job! How long are the J bolts?

[Great Lakes Makes]

I don't know why I'm so hesitant to give concrete a try for something functional. You make it look so easy! Nice work.

[Uncle Kudzu]

Very nice! And achievable by mortals.

[efoster6]

Love the seats now I've got make some the same but when you are mounting the bolts you should use a board that has identical holes the same spacing's and alignment as the seating boards hanging the bolts in to the cement that way you are sure that they will be vertical and the correct spacing's making for easier assemble

[TobiasS46]

I was thinking the same thing. And if you use Nuts in the helical ridge to set the height of the rods you can avoid the height difference so you wont have to bring out the power tools to cut them so they don't poke out of the seats.

[shahin.shaashaa]

it's so nice and i enjoyed see your great work
in my country (better to say in the islamic republic) women cannot have your hobby
have a nice time wooden lady

[AKOldman]

I don't know where you are, but the rural setting looks great! Nice, simple bench. I really like it. Hindsight is 20/20 as we have already seen in the other comments. So WTH, I'll toss out one suggestion for the future. How about using a scrap piece of 4x4, long enough to overlap the sides of your concrete forms. Drill the three, or how ever many, holes with the proper spacing and depth. Install the J-hooks then set them in the concrete. You will end up with the proper spacing between the 4x4s and the proper depth of the J-hooks so you won't have to do any cutting. Hey, I am not criticizing your work at all. I am old, disabled and take forever to get projects done because I try to find ways to make things easier for me. This idea popped into my head right away and I wanted to share it with you. I like your approach to things, I will be subscribing.
jc

[Beagles]

Oregon to Virginia......

https://www.youtube.com/watch?v=zu6qI1Pq60w

https://www.youtube.com/watch?v=mpIY1gOqh8Q

Beautiful new space!!

[AKOldman]

Thanks, and yes it is.

[brookegravitt]

Looks great! I think I’d like to make one.

[Chorophilia]

Great project! I was looking for something like this to put in a shady spot in our yard. Did you stain the concrete? In the final photo, it looks like it has a bluish hue? If you did color it, I'd like to know what you used.

[DebB4]

This is great. I would love to put it 'over' an ugly window well. Would it light enough to slide sideways to access the window well? And could the wood likely span 6 feet without sagging in the middle? I live in N. IL and if there is anyone going to make this, I would buy one from you!

[mb220s]

What a great & simple idea for an attractive bench. A couple of things I would do.
1 I think Beagles has the right idea of pushing the j hooks further.
2 I would have colored the concrete. I believe paint stores or the big box stores carry concrete coloring.
3. Finishing the wood before installing them and also some kind or water sealer between the wood and concrete. "Buttering" the concrete with a thin coat of roofing tar should keep them from rotting.

[Beagles]

Nice benches! A couple of points, you could push the "J" hooks down a bit more to avoid having to cut them off later. At step #7 you could finish that concrete further by parging with mortar or parging cement, both available at big box stores.....gives it a finished professional look.
When you use wooden forms it helps to oil them to stop the concrete from sticking, old motor oil is what I use.

[rring883]

Great job and explanation! Thanks for sharing.

[Kink Jarfold]

I really like the way you approach and tackle a project. As usual, a great job.

[audreyobscura]

The feet on this bench came out great!