Can you stack 2 of these units together?

Unfortunately not; It will not be stable enough and could be dangerous should the top shelf slide off.

You can build a custom shelf, though, by purchasing individual shelves and poles; components can be seen here:

https://honeycando.com/collections/shelving-components

I must be missing something. Why are there no dimensions for the shelves or height?

Dimensions are 24:W x 30"H x 14"D. Thank you for pointing that out; we have since updated the dimensions in the product description above.

I currently have one of these shelving units, is there any way to purchase an extra shelf?

This shelf has a different weight capacity - this shelf is 350-lb weight capacity versus the unit's 250-lb weight capacity - but it would still fit and work out just fine.


https://honeycando.com/products/steel-shelf-350lb-chrome-14x24