Im in the process of making a floor for my hub shelter, its a clam summit 6x8 so what im doing is making it in 3 sections that will be32x72 it will be hinged and fold out flat or fold the 2 sides up when in sled mode to haul the gear out, its going to have 2" Styrofoam insulation under the luan, I dont think it will be to heavy im going with 1/4" luan with 2x2 framework and with the insulation under it there is no need to have any cross supports, the insulation is strong stuff I ran a piece over with my truck and it didnt do any damage to it at all, dont know an exact wieght just yet but if i figured right it should be way under 45lbs where im at we get water on the ice at times so thats why im going with 2" to keep the water under the floor and when we run the heater in it it would eventually start to melt the ice making it sloppy inside so this will no longer be a problem either