I am working on building a travel trailer/tiny home, and we wanted some additional seating. As one needs to make efficient use of space when designing small, the idea of having poufs with storage inside seemed perfect. They fit under a table for easy storage, and have a decent amount of storage space inside as well. I'm pretty excited about them!

Step 1: What You Need

Supplies
1/2" plywood: this would all fit in one 4x8 easily. I used scraps lying around.
25" of 2x4, or 50" of 2x2 for the inside support.
15" x 15" of foam (I had 3" around and used that, if I were buying it I'd probably go thinner).
2 cheap 14" IKEA pillow forms for additional padding on top.
Fabric for cover (I had two pretty pillow cases that I used for the top, and bought 1 yard matching fabric for the rest, fabric not pictured).
hinges/1/2" screws for hinges.
screws for building the frame (2" or 3" works fine).

Tools
Drill
Table saw/miter saw (or whatever you have to cut wood)
Orbital sander or sandpaper
Sewing machine
Staple gun
Glue gun

Step 2: Sand the Wood

I didn't intend to line the boxes with fabric on the inside when finished, so I wanted to make sure the surfaces on the inside of the ottoman would be smooth. I sanded one side of the ply, and did the same for the 2x2 on two sides (as the other two sides would not be exposed), as well as the edge in between.

Step 3: Cut the Wood

I used a miter saw and table saw to make the pieces I needed from scrap lying around.

Cut List
(x4) 12" of 2x2
(x2) 12" x 15" of 1/2" ply
(x2) 12" x 14" of 1/2" ply
(x2) 15" x 15" of 1/2" ply

Step 4: Assemble the Frame

Making sure to have the sanded sides of my ply and 2x2s facing what would be the inside of the box, I attached two of the 2x2s to each of my 12"x14"s using 2" screws. Make sure to pre-drill first, and make all attachments to the 2x2s rather than ply to ply. One screw on either side is sufficient.

Next attach the 12"x15" pieces to your two half assembled sides. Be aware of where your other screws are, so they don't hit each other. Now you should have a square frame.

Last, attach one of your 15"x15" to one side of the box for the bottom. The remaining 15"x15" will be upholstered separately and attached at the end.

Step 5: Cut the Foam

Cut one piece of 15"x15" foam. It is easy enough to cut with a knife, but the successive cuts left a pretty rough edge. I'm sure I could have made a cleaner job of it with something else. Other suggestions for cutting foam welcome!

Also shown is the buildup for what will be the top of the ottoman.

Step 6: Sew the Upholstery

Now to sew the upholstery. First I created a 60" loop with my fabric that will slide over the frame. If your fabric is already 60" wide and a little stretchy, all you need to do is fold your fabric in half with the grain and sew down one side. If it's narrower, you will need to piece it together from two 30" pieces. One yard should be enough as long as it is at least 30" wide.

Cut your loop into two loops, one to attach to the top square, and one for the bottom frame. Leave a few inches on both for wrapping and stapling down later. For me, this meant about 5" for the top and 16" for the bottom.

The next step is to sew the top square to your 5" loop of fabric which will make the sides. In my case I used pillow cases that were slightly larger than 15" square. You could also use more of the same fabric. Regardless, you should have a finished top size of 15"x15" (equal to your frame), and should add a quarter - half inch to that for seam allowance depending on the strength of your fabric. To sew on the top, put face sides together, and pin before you sew all the way around, ESPECIALLY if you are sewing a non-stretchy to a stretchy fabric. Make your seam, and turn right side out.

The last piece of the upholstery is to make a flap for easy opening. I pillow cased, then topstitched, a 1" x 6" strip for this purpose, which will be stapled to the top.

Put your pillow, foam and remaining piece of ply in the top, bottom fabric over the frame, and check out how great it's going to look!

Step 7: Attach Upholstery

For the top, you're going to want to pull the fabric as tight as possible as it will compress upon sitting. If you've every stretched canvas before, I used a similar method. Staple the center of one side, then staple the opposite side tight. Once you have your first four staples, one on each side, continue stapling opposite sides in pairs until the top is tightly and evenly held down.

Do the same for the bottom frame, although because there is less stretching necessary I just moved in a circle around the top and bottom.

At this point, there are many options for making things prettier. I cut the edges neatly and glued them down, and later decided to glue down a ribbon to clean things up further (hence there being hinges in these later photos). You could also line the inside with fabric or paint it for a fully polished look, but I skipped this step in the interest of time.

Lastly if you plan to use this on bare wood floors, it is important to add felt corners to the bottom so the staples don't do any damage.