Building cinder block shelving - question about supporting tanks
I'm working on building some shelving in my basement for plant growing/breeding tanks using 2x4s, 3/4" plywood, and cinder blocks.
I would like to limit the number of cinder blocks I use, mainly because they are heavy. My goal would be to have two cinder blocks-deep 'pillars' at both ends of the shelving (which is about 11ft) and then one-cinder block 'deep' centered pillars at two steps between. Thus, the 2x4s could not be at the edge of the cinder blocks, but would be more centered, and thus could not directly support the edge of the plywood.
How much 'overhang' from the plywood would be considered acceptable from the supporting 2x4 to have a tank's edge be on it?