These DIY square Adirondack chair plans provide a more modern look than the traditional Adirondack chair. These plans are very similar to our DIY Modern Adirondack Chair plans, but offer the same heft of a standard Adirondack chair by being built using mostly 2×4 construction.  They still reduce the complexity of a standard Adirondack chair by removing a lot of rounded cuts and angles.  Plus, best of all, you can build these chairs for about $75 each (or less if you use reclaimed pallet wood for the slats).

Materials

• 3 – 1x4x8 boards
• 4 – 2x4x8 boards
• 1 – 2x6x8 board
• nails or screws
• 4 – 3.5″ carriage bolts, washers, and lock nuts
• wood glue

Tools

• Circular saw, miter saw, or table saw
• Jig saw (optional)
• Drill and driver combo
• Kreg pocket hole jig (optional)
• Tape measure
• Square
• Clamps
• Sander and sand paper
• Pencil
• Pneumatic nail gun (optional)

Step 1: Cut the back legs

The first step in these DIY square Adirondack chair plans is to cut the back legs. Both of these legs are exactly the same, so you’ll repeat these steps twice. Start by cutting a 2×4 to 38 3/4″ in length. Now on the end which will be the front, measure in 1 1/8″ along the bottom edge and make a mark. Connect this mark to the top corner of the same end by drawing a straight line, then cut along this line to form the slant needed for the face of the back legs.

Now from the bottom corner of the back end of the legs, measure 1 1/2″ in, and 1/2″ up. From the top corner, measure in 1″. Connect the three marks as shown in the image below and cut along these lines.

Step 2: Attach the leg face

Once you have the back legs of your Adirondack chair you will now want to join them together by attaching the face board. This board is a1x4, cut to 26″ in length. To attach the face board to the legs you can either use pocket screws from the inside of the legs, or you can use screws or nails through the face of the board. In either case, be certain to use a liberal amount of exterior wood glue as this will provide the real strength of the joint.

Note, the front face board should be aligned flush to the top edge of the back legs. This will leave a small amount of the angled edge of the back legs showing, but not enough as to be concerned about.

Step 3: Attach the front legs

Cut two more 2×4 pieces to 20″ in length, and these will serve as your front legs. You will need to affix the back leg structure to these approximately 5 1/4″ from the top of the front legs. To find the exact position, set your back leg structure so the lower angle cut on the back of the legs rests flatly on the floor then set your front legs in position, offset from the front of the back leg structure by 3/4″ (the width of the front face board). Now glue and screw (or nail) the legs in place. The legs can be attached by pocket screws from the back side of the legs, or by nailing/screwing from inside the back legs into the side of the front legs.

Step 4: Attach the bottom seat slats

Measure back from the inside edge of your front face board 17 3/4″ along the top edge of each of your back legs, this is where your first of the five bottom seat slats will be attached. The slats should then be spaced 1/4″ apart, resulting in the last slat overhanging the front face board slightly. Use either two wood screws or brad nails on each end of every slat to fasten the boards in place while the glue dries.

Step 5: Build the back frame and attach the slats

The back frame is essentially a 28 1/2″ x 23″ box, with a middle support, built out of 2x4s. Cut the two side boards to 28 1/2″, the top and bottom boards to 20″, and then a single center support board to 25 1/2″. Use wood glue and either pocket screws from the inside of the frame, or nails/screws from the outside to secure the boards in place. Make certain to square all four corners as you go, otherwise the back of your Adirondack chair could lean one way or another.

Once the frame is built, secure the seven 1×4″ slats, starting from the top and spacing 1/4″, in the same manner as you secured the slats for the seat.

Step 6: Assemble the base and back rest

This step is probably the most difficult of all of the steps in these DIY square Adirondack chair plans – but we can save you the pain of having to calculate the 110 degree angle at which the back of this Adirondack chair sits by a few easy measurements.  Start by measuring up 15″ from the top corner of the back leg and put a mark in this spot (“Mark A”).  Now, measure down perpendicularly 2 3/4″ from Mark A, and put another mark (“Mark B”).  Finally, measure up another 1″ from Mark B and place a third mark (“Mark C”).  Draw a line from Mark A to Mark C.

You’ll now have a triangle as illustrated in the image below. The front of this triangle is the angle for the back edge of your back frame to follow when you attach it to your leg structure.  Repeat this process on the inside of the other back leg, then attach the back support to the leg structure using two 3.5″ carriage bolts, washers, and lock nuts per side. Drill the holes for the bolts through both the back support and the leg structure simultaneously by using clamps to hold both pieces in place.

Step 7: Armrests

The final step in these DIY square Adirondack chair plans is to cut and attach the arms of the chair.  In my designs, I’ve added rounded ends and a slight taper to the arms – but you can leave them square or get even fancier with the designs if you wish.  To follow my pattern, start by cutting your 2×6 into two pieces, each 36 3/4″ long.  For the front end of each armrest you’re going to draw a 5 1/2″ diameter half circle, touching both sides and the front edge.  This half circle is then your line to cut out the arc on the front of the arms.

After cutting the front arc, make a mark on the back end of the board at 4″ in from the inside edge.  Draw a straight line from this mark to the bottom of the arc you just cut.  This will be your outside taper.   Now draw a 4″ diameter half circle on the back end, touching both sides and the back edge and cut along the arc.

The last construction steps of these DIY modern Adirondack chair plans is to attach the arms. In order to keep them parallel to the sides of the back rests, they need to be offset about 1 1/2″ on the inside of the front legs as in the image below.  Use wood glue and either pocket screws from the inside of the front legs and underside of the arms or nails/screws down through the arms and into the front legs and from the inside of the back support.

Now that your build is complete, finish your new Adirondack chairs as you see fit.  Start with a light sanding to remove any rough edges or splinters, then either paint or stain and seal to protect the chair from the elements.

Please leave us a comment below if you try these plans, or if you have any questions in regards to the build.  And don’t forget to check out our other free DIY furniture plans.

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