So I plan on building a 16 x 32 vinyl liner in-ground flat bottom 5 foot this spring. The steel kit I'm looking at has 48 inch walls. I plan on doing a Ledge the width of the pool and a couple of steps. They want $2,000 for the ledge? Is it possible to just use cinder block and concrete and fill the area with rock? And then use the vermiculite and mortar mix for that like I plan on using for the bottom of the pool?