2x4 Outdoor Sofa

Cut list

Board layout. Each row is one board, cut left to right, with the remainder hatched. Dark lines are saw cuts, about ⅛″ wide.

Build it

1. 
   01

   Cut the pieces

   Measure your cushions first. This fits three 24″ × 24″ seat cushions between the arms, with room behind for back cushions. For other cushions, change the rails (D), back boards (H) and seat deck (G) by the same amount.

   • A Back posts, four at 28″
   • B Front posts, two at 23½″
   • C End cross pieces, two at 31″
   • D Front and back rails, two at 69″
   • E Middle cross pieces, two at 24½″
   • F Middle front legs, two at 12¾″
   • G Seat deck, one at 27½″ × 72″
   • H Back boards, three at 75″
   • I Arm slats, eight at 31″
   • J Arm caps, two at 26″

   Drill six ½″ drain holes through the seat deck (G) so rain can't pool under the cushions.

2. 
   02

   Build the two arms

   For each arm, lay a back post (A) and a front post (B) on a flat floor, 31″ apart at the outside, bottoms lined up. Screw the four arm slats (I) across them with 3″ deck screws, two into each post: the lowest one 3½″ up from the bottom, the rest 2″ apart, the top one flush with the top of the front post.

   Build the second arm as a mirror image, so the slats end up on the outside of both arms.

3. 
   03

   Build the seat frame

   Stand the front and back rails (D) on edge between the two end cross pieces (C): the front rail flush with the front ends, the back rail 3½″ in from the back ends. Drive two 3″ deck screws through each end cross piece into each rail.

   Fit the two middle cross pieces (E) between the rails, centered 27″ and 51″ from the left end, and screw through the rails into them.

4. 
   04

   Join the arms to the frame

   Stand the arms up, slats out, and set the seat frame between them with its top 12¾″ above the floor. Drive four 3″ structural screws through each end cross piece into each arm post.

   Stand the two middle back posts (A) behind the back rail and the two middle front legs (F) behind the front rail, just outside the middle cross pieces. Drive two structural screws through the rails into each one, and two through the middle cross piece into each leg.

   Watch outEvery leg and post must stand on the floor before you screw it, so all eight share the load.
5. 
   05

   Screw down the seat deck

   Lay the seat deck (G) on the frame between the arms, its back edge against the back posts. Screw it down with 1⅝″ deck screws every 8″ or so into the rails and cross pieces.

6. 
   06

   Add the back

   Stand the first back board (H) on edge on the seat deck, against the front of the four back posts, and screw it to each post with two 3″ deck screws. Add the other two above it with 2″ gaps. The top one ends flush with the tops of the posts.

7. 
   07

   Add the arm caps

   Lay an arm cap (J) flat on each arm, flush with the outside and the front, its back end against the back. Drive two 2½″ deck screws into the front post and two into the top arm slat.

8. 
   08

   Finish

   Round over the front edges of the arm caps and every corner people touch, and sand smooth. Seal the plywood edges well, then paint or stain the whole piece with an exterior finish.

   TipUse outdoor cushions with quick-dry foam, and bring them in or tip them up after rain.