Gabel, wow that sounds quite heavy. I have seen smaller ladders where the sides were not hardwood. Have you tried building anything lighter? I did figure the rungs would have to be oak for strength, but didn't think the sides would HAVE to be. I'll definitely take your suggestions under advisement. I actually have some extra white oak slabs that I could rip, but that material is so darn heavy. If using the white oak, I would even think 2X3 would be strong enough for sides. I built bunk beds last summer from ripped 2X3 for the frames from some of those slabs and it was very strong. Remember That I'm going to afix this to the wall, so it's basically all compression except any shear imparted by standing on rungs.