How to Build Corner Benches for the Deck

Great for family gatherings, decks are a versatile way to expand living space. Building corner benches on existing posts of your raised deck is a quick and inexpensive way to add seating that is stout and comfortable. This plan can be built in a few hours using leftover decking materials. For purposes of this tutorial, a deck with 4-by-4 treated posts spaced at 48 inches is assumed. Adjust measurements to fit your situation.

Things You'll Need

• Tape measure
• Circular or handsaw
• 2-by-6 treated lumber
• 5/4 treated or composite decking
• 4-by-4 treated posts
• Lag bolts
• Drill
• Treated deck screws, 1 ¼ and 1 5/8 inch
• Joist hangers and inside corner brackets

Instructions

Cutting the Pieces

1. Cut these pieces from 2-by-6 treated lumber: 2 outside rails, 1 52 1/2 inches, 1 54 inches. Two bench ends at 20 1/2 inches. Two bench faces, 1 51 inches, 1 32 inches. 2 cross members, 19 inches.

2. Cut these pieces from 5/4 treated or composite decking: 4 seat tops 52 1/2 inches; 4 seat tops 30 1/2 inches.

3. Cut three bench legs from 4-by-4-inch treated lumber at 16 inches.

Assemblling the Bench Frame

1. Mark corner and next post on both sidings--form a right triangle using the carpenter's square--at 16 inches above deck. Attach two end pieces using 3-inch lagbolts on this mark on two outside posts, flush with outside edge of post, parallel to deck. You now have 2 "L's" sticking out into the deck 17 inches at 16 inches high.

2. At left post, attach outside rail running from a point flush with the end you just installed to 1 1/2 inches past corner post to outside of posts with lagbolts. Right outside rail attaches opposite, tucking into overlap behind corner post provided by left rail.
   Using square, mark a point on right rail 22 inches from outside corner on inside face of rail. Hang inside of right leg of joist bracket on this mark with 1 1/4 inch screws. Install inside corner bracket on left end, with screws, attach 51-inch bench face between brackets.

3. Mark 51-inch bench face 22 inches from outside of right outside rail, on inside of board. Attach remaining bench face between right bench end and this point using inside corner brackets and 1 1/4 inch screws. Inside of right bench face should be on the line. Add cross member to right top frame between back rail and bench face, with left side flush against right face of corner post, attach with 1 5/8 inch screws. Add the second in left top frame as before, 22 inches from outside of right outside rail.

4. Add legs in right and left front corners, inside frame, flush with top of frame and resting on deck. Attach through face with lagbolts. Place third leg in inside corner provided by face boards, inside frame. Attach with lagbolts.

5. Beginning on right side add bench top. Notch one 52 1/2 inch top piece around right and corner posts, slide to back of bench flush with outside rail. Attach with 1 5/8 inch screws. Add 3 52 1/2 inch pieces in front, flush with bench end, hanging over bench face 1/2 inch. Install remaining bench top as before on left frame. Enjoy your bench!

Tips & Warnings

• Use composite decking for splinter free benches

References

• Built in bench designs