Hello, after reading through many articles here on GreenBuildingAdvisor, we are considering installing rigid foam on the interior wall of our basement (this is new construction). However, I just noticed that our plumber run his lines tight on the concrete walls so we can’t slip the rigid foam boards under. Is there a way to detail this somehow with rigid foam? 

Do we even need rigid foam on the interior walls? When we waterproofed during the construction, we installed R-10 insulation on the exterior of the basement walls. We are in NY, zone 4.

thank you,
Lana