Hey everyone, i'm installing a 15x30 oval pool in New jersey. I have 1 inch thick Extruded Polystyrene sheets for the base. I compacted the direct base with a plate compactor level which was an 18 inch to 0 dig out to get the ground level. I am going to backfill the low side after installing the base and pool. I was thinking about adding a root barrier like a 18 mil plastic sheeting or tarp, used for under concrete slabs under the XPS sheets. Would this be a good idea under the XPS? Is there anything else i need to do for a good stable XPS base?
Thanks in advance for all your input.