Is it a plastic material on the flooring? If so replace with plywood or material of your choice. I've never been successful in finding a weight rating for any cargo bay, motorhomes or towables. Our SB has a plastic material, and loaded up it does bow a bit. I have intentions of adding a little more structure underneath and replacing at some point.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.