a subflooring composite is especially useful in a van . the composite comprises a plastic core having a thin planar bottom surface layer , a thin planar top surface layer and a series of substantially equi - spaced and generally vertically extending support walls connecting the bottom and top surface layers . a foam underlay is adhered to the plastic core &# 39 ; s underside . the subflooring composite has good structural strength , insulation properties , and acoustic qualities . it is readily precut to abut against the interior vertical walls of the van .