thanks. I was just throwing a nice round number out there to make it easier. I guess you take the live PSF number you are looking to get and multiply it by the square footage of the area and that should be the maximum weight it can hold distributed evenly.Yup looks like it
Now...100 lbs/ft live load is a lot. I realize this is Garage Journal and not house journal, but for most residential structures in the US the Live Load minimum is 40 psf (exception for bedrooms). That means if you have a 20' wide mezzanine(just an example) at 10' deep you're designing to put 20k lbs, evenly distributed up there. That's a lot of vises or engine blocks or some other heavy object
If you need to go longer than 10', you'll either need to go to a 2x12, narrow up the spacing between or move to a engineered truss system
that’s a lot. In a decent size building I guess some (most?) people wouldn’t use wood in that situation. It could be fine if you just have a basement underneath where you can have all the posts you want.
I don't think you completely understand the concept. It is impossible to predict how a structure will be loaded so there is a large factor of safety and it allows for flexibility of load placement.
