Cardboard Skyscraper Architecture Challenge

Flat cardboard pieces in assorted sizes — the more variety, the more design options

Tape — masking tape or packing tape

Scissors

Ruler or tape measure for measuring the final height

Pencil for planning

Gather a large pile of flat cardboard. Cereal boxes, shipping boxes, and cardboard scraps all count.

Set the challenge clearly: build the tallest free-standing tower that can support itself for at least 30 seconds without being held.

Sketch a plan on paper before cutting anything. What shape will the base be? How will you add height? Where do you expect weak points?

Start building the base. Wider, heavier bases create more stable towers. A triangular base (three walls meeting at a center) or a square box base both work well.

Add vertical elements. Roll cardboard into tubes — cylinders are structurally stronger than flat sheets. Fold cardboard into triangular cross-sections for even more strength.

Test stability at each level. Gently nudge the tower. If it wobbles, reinforce before adding more height.

Add cross-bracing — small diagonal pieces taped between vertical elements — wherever the structure feels weak.

Measure the final height. Let the tower stand for 30 seconds. Then discuss: what structural choices made it tall? What caused wobble? How could you make it taller next time?

Triangles are the strongest shape in structural engineering. Any time your tower feels weak, add triangular bracing.

Rolling cardboard into tubes dramatically increases strength. A flat sheet buckles easily, but a tube resists compression.

The base must be proportional to height. Rule of thumb: at least one-third as wide as the tower is tall.

Turn this into a competition. Who can build the tallest tower using the same amount of cardboard?