This is a storage rack I designed to hold my recycled lumber, piping, conduit, ladders, etc. I utilized a stack of 2x4s that I stripped out of my house during a remodel project. See the attached images for the dimensions I used. You can scale this up or down, use fewer or more frames, change the spacing etc. to meet your needs and space. The rack as drawn is very stout and can probably safely hold several hundred pounds of material.
I made this rack 12'-0" long with the intention of storing materials up to 16' long, leaving 2'-0" of overhang at each end.
Step 1: Get your tools and materials
The bare minimum you need to construct this rack is about 220' of 2x4, a lot of nails, a saw capable of cutting a 2x4 and a hammer. I used a 10" powered miter saw and a pneumatic framing nailer with 3 1/2" nails. Allow for scrap if buying new 2x4 material. It will also make assembly easier if you have four 12'-0" long pieces of 2x4 to use for the 'struts'. Use at least 2 1/2" long framing nails or wood screws. The attached photo shows the stuff I planned on putting on the rack and how much space it took up before hand.