I've seen a few posts asking about how much clear height is required to install a mezzanine. Well, here's the answer...drum roll...it depends. Why is that always the answer?! Simply put, IBC requires 7'-0" clear height on every level (a few exceptions). So does that mean a 14'-0" clear height will support a mezzanine? No. Clear height is determined by the distance between the floor height to the lowest obstruction (HVAC duct, fire suppression, lighting, truss, ceiling, etc.). "But what if my top level is slanted and I don't plan on having people walk along the shortest area?" Again, no. If the lowest height of your pitched roof is 6'-0" you would need to create a physical barrier to block off that area for potential head knocks. "Ok, ok - so what's the minimum?" Here's my process: 1) 7'-0" clear on the first floor (hvac, etc normally get's hidden in the mezzanine structure) 2) 12" minimum to account for the mezzanine structure and deck 3) 7'-0" clear to the ceiling 15'-0" may be the bare minimum, but very few can make this work. I truly don't like recommending a mezzanine unless there is 18'-0" available, and north of 20'-0" is ideal (I think @Cody Payne mentioned this in one of his posts). If there are any questions about a property/development you are working on, feel free to reach out.