Assess your needs. Determine where you want your firewood caddy to be placed. The site of the caddy will enable you to take measurements to determine the size you can accommodate.
Decide if you want a single level firewood caddy or if you would like a separate storage level for kindling. Using the measurements you have taken, use pen and paper to design the caddy you want. Designing the caddy will allow you to determine exactly how much of each material you will need. It is at this point that you should decide if you want a fixed roof for your caddy or if you will simply use a tarp to keep the firewood dry.
Start to build. For this example, the firewood caddy will be six feet long by two feet deep and will not have a separate compartment for kindling nor a roof. We will use 2 by 4 to construct the base. You will need two have two 6-foot 2 by 4 and four 2 by 4 cut to 20 inches. Standing all the 2 by 4 up so they are four inches tall and two inches wide, place the two 6-foot 2 by 4 parallel to each other with a single 20 inch 2 by 4 place at each end and the remaining 20 inch 2 by 4 placed at two feet from each end. These two 2 by 4 inside the rectangular shape will give the support necessary to hold the firewood. Fasten all the 2 by 4 together using decking screws.
Cut the wire mesh a little larger than the surface area of your newly constructed base. There are wire snip tools made especially for cutting the mesh. You will want the wire mesh to cover the top surface area of the rectangle with a little overhang. Carefully fold the overhanging wire mesh down and secure it to the outside of the 2 by 4 that form the rectangle using either galvanized poultry nails and a hammer or galvanized staples and a staple gun.
Cut four 2 by 4 to a little taller than you wish to stack your firewood. You will also need one 6-foot long 2 by 4 and two 24 inch 2 by 4. The four uprights should be secured with decking screws to the outside corners of the 6-foot 2 by 4 that compose the base. The final three horizontal pieces of wood will provide structural support for the caddy and a stopper to prevent the firewood from sliding off the caddy at each end. The 6-foot 2 by 4 should be secured horizontally using decking screws to the two uprights midway up on the back of the caddy. The two 24 inch 2 by 4 should be secured horizontally using decking screws to the two uprights on either end of the caddy.