Paint on Waterproof Liner For Solar Heat Storage Tanks
I highly suggest to use 2 x 6 supports and run a few more around the preimeter like I did, maybe every foot up as that is alot of pressure on those walls, I have 1.25 thick walls and as you can see I have lots of support and still I get about 3/4" bowing about 2' up, I use 2 x 4 but wish I would have did 2x6, I will be adding more this summer.
Gary Reif