If the chair will have a cushion, account for its compressed thickness in the seat height by subtracting half the cushion’s thickness. Level each set as they are started. The work that we undertook was to construct 6 eight-foot long benches for the skateboard facility in the Gettysburg Area Recreation Park. Keep watch that they are level as they are assembled. Right side, seat 6 1/2" from right back 8" inches (again adjust for any board overage. put a seat railing completely around a 12' x 24' deck using my most comfortable deck chair as a pattern, so I repeated the approach. The following instructions were given and followed: Brief training will be on safety, layout, how to use the jig that was built and used for the prototype. Adams County Master Gardener. For an 8 foot bench, three supports are needed. without predrilling if necessary, but screwing together will go faster if predrilled, so more people won't be standing around. Note that the seat and back will be offset 1/12 inches. For the top screw in the top back board, keep 2" from edge, rest 1". The lower end is cut at a 67.5 degree angle, found by measuring the angle of the back of my comfortable lawn chair. I had previously Using deck screw attach with 2 screws in each back support piece. When the 18 person GIV crew arrived at Gettysburg Area Community Park, we 'counted off' and every third member was appointed team coordinator. Right side, seat 6 1/2" from right back 8" inches (again adjust for any board overage. It's subtle but makes a noticeable difference. Piece three is 16.5 inches long, with the top cut at 7.5 degrees, the angle of the seat from the horizontal. It won’t look right without a back… Spacers are used between seat board and back clamped together before screwing pieces together. This is to reduce chance of splitting the support boards. Piece four is the most complicated, 20.5 inches long with the front angle of 7.5 degrees and the rear angle at 14 degrees. They may be painted after weathering for 60 days. With the lighter 18 year olds, we found that we had to back out the screws and redrive them to get the friction necessary for rigidity. The following sketch shows the numbered pieces and the angular cuts that need to be made. faster with less dead time. That's how I determined the angles and dimensions. These need to be exactly the same dimensions, a target easily achieved by the use of a jig. Our prototype went together quite well with 180# men driving the screws in, however we added 2" x 2" cross braces on the back when a little give was detected. Step three predrill the holes, as drills become available. For the left My jig is shown below, and I will loan it out if desired, email me at firstname.lastname@example.org. Piece two is the simplest of the pieces, being 32 inches long, with no angles other than the length cuts. First, the seat . Then starting at the top of the back of the bench, attach one slat. Ends even or excess between types evenly distributed. Step One, form 5 teams and designate leader. Piece one is the back support, its 36 inches long. This was put together by myself, a Naval Architect, Coast Guard Academy '56 and a Nuclear Engineer, Ray Schwartz, U.S. Military Academy, West Point, NY '67. Note that the pattern chair is to the Bill Devlin Step six, install the middle support, keeping watch they are level. Work flow: Since we have so little time and so many people, we need a workflow that keeps everyone involved. Step four, the critical path will go through the single support jig, so we will predrill one hole per corner assembly, two sets will allow the bench to get started and the third (middle support) can be installed later. Step seven, when all the rest is assembled, install the diagonal braces. Layout boards side by side just as they appear on prototype, three seat boards and 3 back boards. The braces go from the top of the middle support to the bottoms of the outer supports. wood for longevity. Going forward, I recommend that construction adhesive be applied as the joints are made up, and they be rigidly Using your 1/2″ spacers, clamp the next piece in place if adding a 2×4 slat. But this should only be done if you are including a back to your bench. When I was originally approached by Sharron Michels of Collaboration for Youth, United Way of Adams County, to come up with a design, and not readily coming up with plans from a brief internet search, I decided to do my own design. Predrilling is frosting on the cake as the screws can be driven For the left support, facing the bench, the line on seat should be 8" in from the left end, the back 6 1/2" from the left (adjust for overage in the boards, the lines should be offset exactly 1 1/2 Inches. Also, the importance of squareness and accuracy in layout. If you want an outdoor bench with a back, the back should extend at least 16 inches above the top of the seat. Step five, get the benches assembled with two end supports. Making sure the front slat is level with the back support. Bench Seat Slope: If you are anticipating that people will be sitting for long periods, consider sloping the actual seat about 1” lower in the back (over the 16” width). On low decks, deck benches can be plain seats with no backs. All these boards are pressure treated board, and each subsequent back board, to insure esthetics. The following picture shows the completed prototype. A For the occupant’s feet to rest flat on the floor with a knee angle of 90–100°, locate the seat 16–18" above the floor.