Crush Rock under concrete pool bottom


Active member
May 22, 2020
Kelowna, Canada

I am building a steel wall inground sport pool. I am having a PB come in to build the walls, pool bottom and collar. The pool bottom will be concrete.

The PB has recommended I overexcavate 2 inches and put in 2 inches of crush rock as a base for setting the walls and the concrete bottom instead of building right on the excavated bottom.

From what I know, this seems like a good idea, however I cannot find any information on doing it this way. Everything I read says to install right on the earth.

Is this an excepted and superior way to build the bottom and base the walls on? Dig is in good soil, no clay or loam.


TFP Expert
Bronze Supporter
In The Industry
Aug 10, 2017
Morris Cnty NJ
If you have good soil theres no need really. I take out material often due to clay amd build back. It's time consuming. You need to plate compact any stone set back. I use clean stone for the pool floor and then vermiculite. You dont want concrete especially in a sport pool