The Role of Plywood in Building an Ottoman

A furnituremaker who's learning asks about construction materials for a sofa. October 26, 2013

(WOODWEB Member) :
I have a question regarding using birch plywood in furniture. I am new to furniture making. My current conclusion is that using solid wood is the best bet for most applications. It holds the tacks well, and is strong. Most applications of plywood would be useless except for one thing...

I am building an ottoman for a designer. He gave me a sketch of it, and I am not sure what it is really called, but it is 32" wide by 58" long, and 19" tall. More of a sofa size ottoman. It is huge. It will be fully upholstered, with a large thick cushion on top. Most likely fastened.

I built the frame out of 4/4 alder, and now I am not sure what to do for the top. Common sense would tell me to use birch plywood rabbeted into the top, as it is structurally sound, comes in big enough sizes so I am not using a bunch of joined alder for the top. Plywood keeps its shape, and will endure without any warping. And since the upholstery gets stretched around the top, I assume staples would not be a problem since none go into it.

But I am not sure if the upholsterer would prefer using webbing or springs on the top instead, or what the standard is for something that size. Is there anything I am missing? Would plywood be okay for this application?

I am trying to make higher end furniture for this client, so material cost is not the issue; it is more durability and quality. I am just not sure what the upholsterer will prefer on top - my guess is 3/4" plywood will be okay.

(Furniture Making Forum)
From contributor G:
We use regular 3/4" plywood for the tops and screw it from below through the corner blocks and an edge rail. The entire plywood piece is upholstered then attached to the base. We cut out the center leaving a 4" edge on the plywood for strength then use elastic webbing for the center.

From the original questioner:

Well, I am not sure about the size. Should I leave a cutout for webbing? Or leave it solid, and let the upholsterer decide? It gets upholstered with that style where the tacks show along the bottom edge, with curves. No feet, but almost solid. Ah forget it, I would have to post a picture. I can't describe it!

From contributor C:
Try asking the upholstery guy?

From contributor J:
Yeah, this would be the sort of thing to collaborate on with the upholsterer before you build the frame, so you have a solid understanding of what he needs to achieve the sort of product you're going for.

Also, the bit about most applications of plywood being useless is wrong. Plywood has particular properties that make it useful in particular ways; solid wood and plywood are not competitors for the same roles.

From the original questioner:
I used alder for the frame, and 3/4" cabinet plywood for the top. It works great, and if the upholsterer decided to remove the top to tuck the fabric, I connected it without glue so it can be removed. And if she needs to cut slots, she can just ask me later.

We have a different relationship here than many clients. I am not into large production, but rather small replications and custom furniture and cabinets. So I cannot always consult with the upholsterer.

And the designer, although he knows what he wants, does not know anything about construction methods, so when I start talking about mortises he gets the typical dumbfounded look on his face. He doesn't care - just as long as it looks like he wants it to. (Fine by me!)

From contributor G:
You will learn as you go along. There is no need for a cabinet grade plywood. We use inexpensive 3/4" plywood since it is strong and totally covered by upholstery. We do a lot of re-upholstery and see the MDF and waferwood inside some expensive pieces of furniture. You will need to understand some basic upholstery to make various frames. Some have nails around a panel in front of a rolled arm. This is actually a separate piece of 3/4" wood that is upholstered then attached to the upholstered frame. We also need slots at certain spots to pull fabric through. If the piece has nail trim you need to be sure the solid wood is thick enough in those areas to allow for staples and nails. Pitch of the back is critical and varies from 100 degrees to 110 degrees and will impact the comfort in a big way. Once you get a few frames built and upholstered and learn the basic things you will be good to go.

From contributor P:
I would make an effort to get in touch with the upholsterer at some point in the near future. I would also shop around for others. Some are much better than others. There is more than one way to upholster a chair - foam versus hair, hand stitched edges, etc. I am no expert on upholstery at all but some day you may get a client that demands a certain look.

From contributor M:
Typically, a full plywood substrate will result in excessive firmness and add a lot of unnecessary weight. Does that bump it out of the high end? Upholstery also likes to breathe, especially if made of natural materials. A piece for normal folks should be able to have a glass of water spilled on it without growing moldy, but my idea of normal is likely skewed. Things to consider for next time, maybe.