Simple Japanese Inspired Arbor Build Under $100

Materials

- Two 4x4x10 pressure treated for outdoor/ground contact

- Three 2x6x8 pressure treated for outdoor/ground contact

- 1/4" x 12" threaded rod - Four 50lb Bags of fast set concrete

- 1 50lb Bag of pea gravel

- Wide painters tape

Tools

- Circular Saw

- Compound Miter Saw

- Universal Saw Stand

- Chisels

- 2lb Hammer

- Wood Mallet

-Flush pull saw

-Square

-Saw horses

-Clamps

-Drill

-Impact Driver (or screw driver of some sort)

-Mortar mixer (you can also do this with a wheel barrow and shovel

This is part of a larger build I am doing but the same method can be applied if you are building the arbor over a path, or anyplace really.

Clamp the 4x4’s together and measure 12” from the end which will be the top (6” for the 2x6 + 2” for the space between the horizontals + material to support the circular saw during the cuts) and using a square mark a line across. Mark another line 4” from the same end. The space between these lines is where the you are reducing the width of the 4x4.

Adjust your circular saw to 1” depth and starting with each line, make cuts every ⅛ to ¼ between the lines. Using a chisel and wood mallet, remove the material you have cut and use the cut lines as depth markers so you do not chisel too deep. Flip the clamped 4x4’s and repeat.

Cut the 4x4’s down to 9 foot making by first removing the excess material at the end of the shoulder. After the shoulder there should be 8” of material and once cut from both sides you should end up with 9f 4x4s.

Next cut the 2x6’s down to size. The top 2x6 is cut down to 6f6 and the two 2x6s which sit on the shoulder are 5f6. Check each end and lop off any material you do not want as part of the final piece before making the final cuts to size.

Both of the bottom 2x6s need to line up with the square mortise in the 4x4. The easy way to do this is to first mark the center height 2 ¾ of the front side top to bottom of the material above the shoulder, and then mark another center 2” from the outside. This is your center point for the mortise. Now create a 1” square around that point. Score the edges of the square on both sides of the 4x4 and then drill through the center using a ¾” bit to remove some material and make chiseling faster. To finish up, uses your chisels to remove the rest of the media inside the square. Whenever makes

For the 2x6’s the same method is used. Mark your center point of the square 3” (the overhang) + 2” (to the center of the 4x4 mortise) and then 2 ¾ up from the bottom. Make the 1” square using that point as the center and drill/chisel out a square mortise.

Apply the same method to each end of each of the bottom 2x6s

I like to stain outdoor projects like this before install and then put a second coat on after installation. It helps to take care of any hard to get spots. Using a 2” roller with an extension pole is the faster method I have found to stain outdoor lumber.

Dig your post holes just over 2ft deep and 12” wide. Add 2” of gravel for drainage and then use the 4x4 to compact the gravel.

Set the first 4x4 by using scrap material and some screws while holding a level to the 4x4 to get it plumb and true. Do this on two sides.

Add the gravel and second 4x4 but do not plumb it up yet. Connect the two 4x4’s using the top horizontal 2x6 and inserting the threaded rod into the drilled mortises on the bottom. Now using a level on top of the 2x6 double check that your depth/grade/amount of added gravel is correct as well as the width between the 4x4s and if not make any needed adjustments. This is when it’s very helpful to have an extra pair of hands.
After adjusting, true up the second 4x4 using the same method as the first and then add a few more inches of gravel and then concrete into both post holes.

Using tape, secure the first 2x6 on the 4x4 solder to make sure it does not fall and then add the second and secure them into place with clamps. If everything else is level this should be perfectly level but always a good idea to check.

Make wedges long enough to generously fit through the mortises from any scrap material that is suitable for the outdoors. Mine were the correct height but a little narrow so I made some extra to fill any space to the side.

Clean out the square mortise with a chisel if needed and then using a mallet tap the wedges in from both sides. At some point the wedges will grab but if they do not you can keep one side in place with a clamp while tapping the other side into a secure fit.

Cut off the excess using a flush pull saw and beware of any cupping happening on the 2x6s that may result in scuffing up the stain while sawing.

Apply a final coat of stain and you are finished! Enjoy your new Arbor!