Gazebo - Part 3 Structure and Bench




Introduction: Gazebo - Part 3 Structure and Bench

This is Part 3 - Structure & Bench, of the Gazebo series. Click here for part 1 and part 2.

This part of the instructable is about the wooden elements of the project. The structure portion was put up many months ahead of the bench, as it took me quite a long time to decide on what to do there and then figure out how to execute it. In that time i learned a lot and wish I could redo the upper joists...

In total it fits the purpose to create a gathering area and separate the "domestic" part of the yard from the "wild" part. I think we succeeded, and the wife loves it! But I'll let you all be the judge.

The following steps will walk you though how I completed it, and the successes and fails i had along the way!


  • 4ea 10'x4"x4" redwood posts
  • 3ea 8'x8"x2" redwood joists
  • 9ea 8'x4"x2" redwood joists
  • 12ea (or so) 8'x0.65"x4" redwood slats
  • 3" screws
  • brad nails
  • lag bolts (if desired)
  • 2gal of SPAR, a clear outdoor wood sealant (fantastic stuff i read about in Handyman) I used the minwax brand.

Tools (some are optional but make the job easier and higher quality)

  • Chop saw
  • Japanese hand saw (I have the harbor freight one and it work great)
  • Jig saw
  • Skill saw
  • Router w/ straight bit
  • Drill
  • Level
  • Carpenters square (the little triangle with a perpendicular edge allowing for 90* marks)
  • Brad nail gun w/compressor
  • Glue
  • Paint brushes
  • Pencil

Tip for success, coat all the boards with SPAR ahead of placement!

Step 1: Step 1: Setting the Posts & Joists

**safety warning, there is a lot of ladder work in this step. Make sure you have good footing for the ladders and if something is uncomfortable, STOP. I tired to do as much work from the ground as possible, maybe it can all be done on solid earth. Falling from a ladder is serious and kills many professional workers each year.**

Setting the 4x4 wooden posts should be the easy part! Since you already have the anchors in the concrete piers at the correct location, all you have to do is set them in place and make plumb before screwing them in. I wish I had used better embed anchors for this as mine turned out a little wobbly.

But before we set the post, we attached the joist to the 2 "center" posts. To do this I employed the traditional "kerf" method to inset the joists in to the posts.

  • Spend some time making sure the post and joist are all square
  • Mark your top and bottom lines of where the joist will be on the post
  • Set your skill saw to the desired depth of the cut (I chose 1")
  • Make one cut along your top and bottom mark each
  • Continue making frequent cuts spaced 1/4" apart or so
  • Clean out the left over pieces with a hammer, flathead screwdriver, and chisel
  • San clean
  • Test fit inset board and make adjustments if necessary

I wanted to try inset lag bolts for a rugged look, here's how we did that:

  • Find center on your joist using the X method (pictured above), then mark 1/2 way between that mark and the top and another for the bottom (so that you have 3 marks in total
  • Drill a pilot hole through the joist and the beam
  • Using a larger wood bit, make a hole larger then the bolt head and slightly deeper then the bolt head
  • Glue the pieces together and drive the lag bolt into the pilot hole (with a washer)

Finally we set the first two posts!

Follow with the 2 other posts, get them plum and screw them into the embeds. Now is where I did one thing, but found a better way later. To set the other two joists, hold them up on the posts and mark where you need to cut the first set of joist and post, then cut the joist.

Next hold the joist up again and approximate the angle it will intersect with the independant posts. Attempt to make another Kerf cut into the new posts. (that is the part that i am not pleased with. Later I'll explain how I did this better on the bench.)

Cut an angle into the joist that intersects with the original posts. To do this, hold the joist up between the two beams, and set a 2x4 flat against the post and beam (see pic above) transfer the line with a pencil. Make the cut.

Finally, with a helper raise the joist, clamp onto the posts, and either screw or use the lag bolt method to attach. Glue is always a plus as well.

Step 2: Step 2: Setting the Bench Joists

Setting the joists for the bench is easier because you don't have to work from a ladder! For this step I refined my method for placing the joists by using a router and a guide. This worked fantastically!

Make your Mark - figure the height you want your bench to be at, consider the thickness of your bench slat material to be on top of the joists. I ended up making my top of joist mark at 14", this is a little short and i think 15" would be great. Mark the top and bottom of the joist thickness on two posts. (I did one joist, or two posts, at a time).

Set up your guides - using two straight 1x1/2" boards, clamp or nail them so that they go between the posts with the angled cuts (the two "sides", not the back joist). they should be set above and below your marks, so that your joist will fit in between them.

Make the cut - using the router, side it along the guides and hog out the material. Uses a couple passes at increasing depth. This yield you a flat and smooth angled surface to attach your joists to, and is a very strong connection.

(repeat for the other joists)

Attach - glue and screw the joists into the new cuts. Cut the two sides flush to the back posts and finally glue and screw the back joist in.

Repeat the process for the back rest. Ours is set about 17" above the bench joist.

Step 3: Step 3 : Building the Bench Frame

There is a bit of guesswork in the bench frame, a lot of measuring and fit up before making final cuts. This step takes longer than you think, lol

Starting with the two "side" benches...

Decide your bench width, we chose 18" and wanted the slats to extend 1" on both sides of the joists. So the joists should be 16" apart (measured on the outsides). Once you know your desired measurement, use some scrap and make a marks 16" apart. Clamp these guides to the back seat joists, and align with the builder's square to 90*.

Next, cut a kerf into the 4x4 bench post to accept the full depth of the front bench joist. Then cut the post to the desired height.

Now temporary clamp the front joist to the seat post and align with measuring guides you clamped up. Your shooting to run parallel with the back seat joist. Once you think it's good, mark (use the 2x4 offset method from before) and cut the joist so that it is flush to the back seat joist. Glue and screw the front seat joist against the intersecting back seat joist. (the seat post is still not attached, just temp clamp)

Clamp a small 2x4 to the end posts. figure out how long it needs to be to go from the front seat post, to the back of the tall posts. Be careful to keep your front seat joist in line with your measuring guides. Also, adjust the position of the seat post so that it intersects these to joist (pictures above are helpful in understanding this.) Once everything is jive turkey, glue and screw! Repeat for the opposing side.

Ok, so the sides are done, now time for the back bench...

Setting a joist on top of the the seat frame so far, measure 16" at 90* from the back of the back seat joist. Align the last joist to these marks. Then trace lines at the intersections (see graphic), all marks will be on the bottom of the joist. Also, trace lines on the top of the two side front seat joists, where this piece intersects..

Make cuts to the front joist of the back seat - trim the ends to the angle marked. make a 1.5" deep Kerf cut into the middle marks.

Cut 1" or so kerf cut into the top of the tops of the side bench front joists where you marked.

Cross your fingers and test fit the back seat joist into place. a Little tight is better then a loose fit. Cut out more material if needed to make the pieces fit. Then glue and screw the whole thing together.

As an afterthought, but not necessary, I added two more posts under the inside joints. And added a 2x4 between the inside joints and the back posts. This 2x4 was for holding up the slats, and was needed for the pattern I chose.

Step 4: Step 4 : Preparing the Bench Slats

Decide what material and width to use for the seat slats. I was going to use a hard wood, but it was going to be quite expensive. So while looking around my local Home Depot I found these 3.5" wide, .65" thick, 8' long redwood slats. They were really smooth, straight, and had beautiful color. Choosing this material also reduced the material cost by half, and it still looks great!

Purchase your estimated amount of material and coat with with the SPAR. While coating these, I found it easiest to coat the wide sides first. Then make the cuts, clamp them all together, and coat the ends and skinny sides.

Cuts - knowing I had to make 100 or so cuts, I decided to make a jig. (I am going to do another instructable on jigs in general, but I'll explain what this one looked like.) The cuts needed to be at 18", so i made a stop block at 18" from the saw blade. I would pull the board into place, make the cut, remove the 18" piece, and continue to pull the board up to the 18" stop. To make jig a too two pieces of 2x4, one long one short. screwed the short piece at 90* into the long piece and placed under the saw so it wouldn't move. (the pics above) Make all your cuts.

Sand - I had some light cutting damage to the boards, so I ran a sanding block over all the end cuts a couple times.

Coat - Finish your coatings by clamping all the 18" slats together and coating the sides and ends.

Step 5: Step 5 : Setting the Bench Slats

Now for the Piece de Resistance, the bench slats.

I desired a look that was thin spaces between the wood slats, and the wood slats arranged in a perpendicular fashion to the joists.

For this I devised another jig (see the photo above). I did this for uniformity and speed. To create the jig find a piece of wood that is the width you want for the gap between the slats. Fix that perpendicularly to a 2x4. Then make "stops" set back 1" from the front of the 2x4. you should end up with something that looks like a cross.

Now, I wanted to start in the corners because I wanted a symmetrical look at the joints. I placed a ripped 1/2" piece of the redwood along the top of the small 2x4 I added in the last step before. Then starting at the corner cut my first slats by hand to fit in the corners and have a symmetrical meeting point.

Attach the stats to the joists using a brad nail along the corner edges. I did my first one on the top, but redwood is so soft there were major puncture wounds. Working it at an angle on the edge worked best.

Production work - once your first slats are in place and you have room to use the jig you can really get moving. set the jig against the front joist and the first slat. If you've done everything right so far it should meet up nicely. Then put your next slat into the jig on the opposing side and nail the exposed edge. Continue in this fashion until you reach the end of the joist.

*note - I worked my way to the middle on the back bench and split the difference on the last 3 boards. You can hardly tell the difference. On the side benches just work from the corners to the end.

Once the slats are placed, nail the other side down. And congratulate yourself for a job well done!

Thank you so much for reading my lengthy instructable and I hope you learned a few things and were inspired to try something on your own. Happy hammering!

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    Daniel James
    Daniel James

    4 years ago

    Decoration is very important to make both garden and home beautiful. And gazebo plays a major role for that. One must learn how to make a gazebo from here. Also there are many online stores for gazebo. Before some months I had contacted with SunJoy Industries for the same. They really provided me best product with very low price.Thank you.