Foam board on the bottoms is the only way...... then insulate in the cavities as WW correctly stated.
Ninkii Xil.Axmed Yaasiin Ee Dhimbiilha Onkodi jiray Waa Muxaafadoobay Maxaa sababay ... Wadada Ceerigaabona Way Reer Bariyeysan tahay Siduu u Arkaa.