Build a DIY Upholstered Sofa: The Frame Plans

How to Build a Sofa

In Part One of the DIY Upholstered Sofa series, I outlined the supplies and materials needed to build the sofa. In this post, Build a DIY Upholstered Sofa: the Frame Plans, I give step-by-step instructions (in plan form) to build a super-solid base for this fabulous sofa! So, let’s get started…

Build a DIY Upholstered Sofa Frame Plans

For this sofa, I built the same DIY legs I made for the upholstered chair. I figured this way, it would tie both furniture together, plus the legs are super-easy to build! The seat frame is constructed using 2x4s with 2x3s as supports under the seat, and the back frame is constructed out of 2x2s with a 3/4″ plywood layer over it. The pieces are joined together (AFTER upholstering) with 1/4″ x 4″ washer head lag screws for the ultimate stability! I used a pocket hole jig to connect the frame pieces to the legs, and countersunk screws to assemble the back frame.

Build a DIY Upholstered Sofa Frame Plans_Dimensions

To Build the Seat Frame:

Step One

Cut the 2×4 pieces for the frame.  With the pocket hole jig set for 1-1/2″ material, drill pocket holes in each end of each piece, including the 2×3 seat supports and the 2×4 back support. Assemble the seat frame as shown, using glue and 2-1/2″ screws.

Build a DIY Upholstered Sofa Frame Plans_Seat Frame

Step Two

Secure the 2×4 back support piece to the sides of the frame using glue and 2-1/2″ screws. This piece is a sort of “stop” for the back because the back leans back 15°.

Build a DIY Upholstered Sofa Frame Plans_Back Support

Step Three

Secure the 2×3 seat supports to the front of the seat frame and the back support, with the bottom edges flush using glue and 2-1/2″ screws. These pieces provide support to the frame but are not as tall so they won’t be felt through the seat webbing (in the next post!)

Build a DIY Upholstered Sofa Frame Plans_Seat Support

To Build the Back Frame & Base:

Step Four

The frame pieces are all cut a bit differently, some with angles at the top and bottom facing in different directions. Looking at the drawing below:

  • The longest top piece will be cut at 62″ with a 22.5° angle at each end (the angle will help form the rounded corners on the back).
  • The next short pieces in blue are also cut with 22.5° angles at each end.
  • The outer pieces in coral are cut as a left and a right with a 22.5° angle at the top and a 15° angle sloping toward the front (this will allow the back frame to lean).
  • The center pieces in green will have the same 15° angle sloping toward the front.
  • And last, the lower pieces in purple will have a 15° bevel cut along one long end of each piece.

Assemble the frame using glue and countersunk 2-1/2″ screws. (Have questions? Let me know!)

Build a DIY Upholstered Sofa Frame Plans_Back Frame

Step Five

Cut the piece for the back base. Cut the corners and notches using a jigsaw. Secure the base to the back frame using glue and 1-1/2″ screws through the base into the back frame.

Build a DIY Upholstered Sofa Frame Plans_Back Base

Build a DIY Upholstered Sofa Frame Plans_Back Frame & Base

DO NOT attach the back frame assembly to the seat frame – this will be done after the upholstery is complete! Stay tuned because the next post, Part Three, is all about adding the seat webbing and the upholstery!

Have questions so far about how to build a sofa? Leave a comment below!

Originally posted 2019-10-25 08:00:57.


  • […] Sofa series is about the DIY upholstery. (In case you missed them, here are Part One and Part Two!) To me, the upholstery is the easiest part. The upholstery is easy to do, and doesn’t require a […]

  • Alex Shaffer says:

    I’m trying to build a specific sofa and I have a few issues. One is the arms of the sofa are supposed to appear like solid pieces of wood with no seem and slightly rounded edges. It will be completely lacquered to finish it. Can I just build a frame and cover it in plywood and then use wood filler and sand it then lacquer it to achieve this look or is there a better way?? I also need help building the blueprint for the frame of the sofa. Any help with that would be greatly appreciated. I’m trying to build poltronova’s Saratoga sofa designed by massimo and Lela vigneli.

    • Cher-Ann says:

      Hi, Alex! To me, it looks as if each arm is a box with mitered joints so that it appears as if it is a solid piece of wood. (See my post on how to make a lamp base from plywood to see how this goes together: I’m not entirely sure how wood filler would appear under the lacquer but it would be a good idea to give it a try with a few scrap pieces before committing to anything huge! And who knows… the plywood edges, smoothly sanded with a few coats of lacquer might look better than the mitered joints! Hope this helps!

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