After buying a few pieces of furniture, I had a number of large pieces of cardboard left over. Rather than just throwing it all in the dumpster, I decided to make a coffee table with it instead! I wanted to make it fairly sturdy, so I thought I would try forming the cardboard into triangular beams as the basis for the construction.

What you will need:

Cardboard - lots of it!
Glue - a big bottle of white glue
Something to cut the cardboard - like a box cutter!
A straight-edge or ruler - to help make the cuts straight!

Step 1: Cutting the Cardboard

I had two long boxes that provided most of the material for the table top. I used the width of the boxes to determine the width of my coffee tables, but you can cut yours to whatever width you desire. The length of the table is determined by how many beams you can get from your cardboard. Cut the cardboard into sections that are 30 ribs wide. (Your cardboard should be all the same type so you can can measure pieces by just counting ribs.)

Score the pieces into sections that are8-8-7-7 ribs wide. Fold the cardboard on the scores, roll it up into a roughly equilateral triangle, with the two ends overlapping. (The image below shows a crosssection of what it looked like.) Glue the overlapping sections together and you should have a nice, strong triangular tube of cardboard.

Step 2: Start Constructing the Top.

One large flat piece box is used for the table top. Lay it on the floor, putting the side you eventually want to use for the top face down. This will give us a nice flat top when we are done.

You are going to glue your tubes from the previous step perpendicular to the ribs in the cardboard for the top. Leave some extra cardboard around the edges, because we are going to wrap that cardboard around the edges to finish it off. Glue the pieces with the double thick face down and just butt them up to one another.

You can see my tubes here all glued down and ready for the next step.

Step 3: Fill in the Bottom

Now, we are going to fill in the space between the existing struts with additional pieces. To save on cardboard, we are not going to make these full triangles. Instead we will have pieces that have one side the same width as the original triangles long side and enough cardboard on either side of this to glue it in place. I found about 4-5 ribs worth was sufficient.

Step 4: Finishing the Top

Now it's time to trim the top piece and wrap it around the bottom to hold the whole thing together.

The two end sides are trimmed and scored so they just fold over the end face of the table, giving us some nice edges.

The sides are folded all the way around so they can be glued to the bottom of the table top. They should over lap by a good inch or two so we can glue them down nice and snug. Then trim them so they are flush with the angled edge of the table. In order to hold the sides in place while the glue dried, I created some makeshift clamps by cutting a notch in some spare cardboard that fit snugly around the piece.

When all this is dried, fit one last piece to cover the rest of the bottom. This doesn't need to be real fussy as it will not be visible once the table is put together.

Time to make some legs!

Step 5: Creating the Legs

The leg assembly uses the same basic idea of triangular tubes. The legs themselves are made from two 45-degree right triangles glued together to make roughly-square legs. These are connected by the skirt pieces that are made from right triangles with one short side and one long side. The exact sizes are all aesthetics, so use your own discretion. This whole thing should end up being smaller than your table top by an inch or two, so size things accordingly.

Glue the leg pieces together and then glue the legs to the skirt. Build the whole assembly upside down so you get a nice flat 'top'. (Assuming your floor is relatively flat, that is!) I used a corner where the floor meets the wall to get a good right angle where I needed it.

Almost done now!

Step 6: Final Assembly

All that is left to do is flip the leg assembly over and glue the top to it. The bottom of the table top ended up being something less than flat, so I used some small pieces of cardboard as shims to fill in some of the gaps.

The final table turned out to be surprisingly robust. I can actually put quite a bit of weight on this without any problem. (Though, being cardboard, it will dent easily.)

You can finish this off by painting it or using decoupage or some other finish to make it more resistant to water and dirt from usage.