How to Build a Frame for an Upholstery Couch

Set out two 1 1/2-by-3 1/2-by-22-inch boards on the working surface with their largest faces flush with the working surface. Adjust their spacing so they are parallel to each other, with 17 inches of space between them. Set two additional 1 1/2-by-3 1/2-by-22-inch boards on top of the boards perpendicular to the original boards, so that the four boards make a perfect square. Overlap the four boards at each corner so the edges line up evenly.

Drill four holes straight down through the top boards and into the bottom boards at each overlapping section, being careful not to drill all the way through to the working surface. Set 2 1/2-inch wood screws within the holes and tighten them securely in place. Repeat this process to create three more of these squares, which are the leg braces, using twelve additional 1 1/2-by-3 1/2-by-22-inch boards.

Stand up the four leg braces, parallel to each other and staggered about 12 inches apart. Lay five 1 1/2-by-3 1/2-by-48-inch boards atop the leg braces, so that each end of these long boards, which are the couch seat boards, are about four inches inset from the outside edge of a leg brace, and the inner two leg braces are evenly spaced between the outer two. Adjust the couch seat boars so the front and rear couch seat board are even with the front and rear of the leg braces and the remaining couch seat boards are evenly space between.

Drill two holes down into each couch seat board and into each leg brace underneath it for a total of 40 holes. Set a 2 1/2-inch wood screw into each hole and use a drill to securely twist it down to the wood surface.

Stand up four 1 1/2-by-3 1/2-by-34-inch boards behind the couch with the help of an assistant. Set the largest surface of these boards, which are the rear boards, against the back of the leg braces, partway up the leg braces so that 24 inches of the rear board shows above the couch seat boards. Drill four holes through the back of each rear board and into each leg brace. Secure the rear boards with 2 1/2-inch wood screws drilled all the way into each hole.

Hold three 1 1/2-by-3 1/2-by-48-inch boards, which are the backrest boards across the rear boards with the help of an assistant. Space them out evenly on the rear boards, with their largest surfaces touching the rear boards. Drill two holes through each backrest board and into each rear board for a total of 24 holes. Set 2 1/2-inch wood screws in each hole and tighten them to secure the boards together.

Place a 1 1/2-by-3 1/2-by-8-inch board in each corner of the seat board area, with its largest sides facing the front and back, and its front and side even with the front and side edges of the seat board area. Drill upward through the seat board and into the bottom of this small board, which is an armrest brace. Attach the armrest brace to the seat board with 2 1/2-inch wood screws. Repeat for the other three corners with three additional 1 1/2-by-3 1/2-by-8-inch boards.

Set a 1 1/2-by-3 1/2-by-22-inch board across each pair of arm rest braces to serve as the arm rest. Drill down through the top of the arm rest and into each arm rest brace, making two holes. Set 2 1/2-inch wood screws in each hole and tighten them to attach the arm rest.