I just built the RCCA ramp today, I used 25/32" 4' X 8' plywood as to eliminate the flex problems that occur with the thinner ply's. I can increase the height thanks to placing hooks on the chain ends and screws at various points on the side, I recommend that you use a thicker type chain than they state, the small links will stretch then bend, I found that out the hard way. All in all it only set me back $26 at Lowes and they did the cutting for me. It folds up in no time and is pretty portable, any one with no mechanical or carpentry skills can make this ramp, you can go cheaper with the thinner wood, but the wood was only $20 and the rest just added up with 2 bucks here, .60 cents there, you know, but all in all, it's nice, hope to use it tomorrow and I will post some pics.