How to Plan and Build My New Metal Building Kits – Part 11 – Mezzanines

This chapter of our series is dedicated to mezzanines for your new pre-engineered metal building kit.

If you are considering a mezzanine or a second floor over an area of your metal building you must plan for it at the design stage – which is now. Even if the mezzanine is not to be installed until a later date it is best to have the structure designed for it at the onset. It will be much easier and less expensive to have this special engineering and structure design done now.

Mezzanines tend to stiffen the building’s structure and create further loads on the main frames. This must be accounted for in the steel design and also in the foundation design.

The specific type of mezzanine must be identified. Mezzanines that are attached to the main structure can have one of many different floor systems. Intermediate support columns are often required (again requiring footing or foundation design).

These intermediate columns are attached to each other and the main frames by a grid-work of beams. Across these beams you could have steel joists with metal decking and a concrete topping.

Your second floor could consist of a much deeper metal decking with a reinforced concrete topping.

A third common practice for mezzanines is to install pre-stressed concrete slabs across the beams. This system is much faster than the two previous methods. Another advantage of this system is that the second floor support structure (the concrete slabs) often do not require fire-proofing in commercial, industrial or institutional (ICI) settings. However, this system can be somewhat more expensive than the other two.

You can of course install a wood framed flooring system for your mezzanine in your metal building. You will likely have to provide a higher fire-proofing value to this type of framing structure. In some areas, building codes prevent the use of combustibles in ICI buildings. This system is also allows more noise transmission from the second level when installed.


  • Information that will/may be required for the design of your mezzanine:
    • Size ____
    • Start at frameline ____
    • Finish at frameline ____
    • Distance from a sidewall (If any) _____
    • Intermediate support column locations _____
    • Type of flooring system ______
    • Use of Mezzanine ______
    • Live load (sometimes dictated by building codes) _____
    • Wall partitions (to determine partition loads) ______
    • Collateral loads (any special loading requirements) _____
    • Height for mezzanine ______ (This includes your clear height requirement under the mezzanine and the clear height required from the second floor to the underside of the haunch of the main frames. You may find here that the height of your building might have to be adjusted to accommodate these clear height requirements)


Don’t forget to plan for the required stairs from your second level. Some building codes require that after a certain size you must have a stairway directly to an outside door. This can mean a little juggling of the space on the first floor to accommodate the stairway and exit door. (This is another fire safety issue).

It is important to note here as well that you can have the metal building supplier include for the design and main frame structure alterations only and then source the other materials yourself. However this can be somewhat risky if you change the design or materials after. Your building may lose its warrantee if you do not install the floor system exactly as designed.

Another note to make here: If your mezzanine is not going to be attached to the framing of your metal building kit then you do not have to plan for anything in the structure itself. You will however still have foundation design work to consider.



Check out Part 12 - Planning and Constructing Metal Building Kits – Cranes



What to Do Next

· Take a look at the next installment in our series.

Check out the other articles relating to metal building kits and residential building packages on our Metal Building Kits Articles Map