Hello,
I recently got a custom pantry cabinet made to fit a niche in my space. Essentially, the cabinet has 0.75” MDF walls and a 0.75” plywood base.

The dimensions of this deep space are 30”x39” approximately. It is sitting on a wooden frame at the bottom (ie no legs).

The purpose is to keep miscellaneous oversized items here and it’s worked out great shape-wise. However I’m trying to determine how much weight I can store on this base. The cabinet maker tells me that this is the thickness used for subfloors in the houses etc. and therefore I should be ok, but I’m sure there are joists running underneath that provide structural strength.

The cabinet is installed and then he broke the news to me that he did not use any additional support underneath aside from the peripheral frame on which the cabinet sits. (Earlier we had discussed adding those additional supports.)

I googled and found that 3/4” ply can carry upto 50 lb per sqft without caving. Can I assume that my cabinet floor will hold ~200 lb without caving? I intend to put some boxes filled with somewhat heavy stuff here.

I have a scale and I’m willing to ensure I weigh stuff before storing here but I want to make sure I know how much load to put.

Thank you in advance!!