Expert: Bruce E. Johnson - 5/11/2010

Question
Hi,

I plan on building a garage this summer. The dimensions are 26 feet by 26 feet. It will be on a concrete foundation. The garage will be built into a hillside, so the parking area will be the first floor, not the basement area.

The floor will consist of 2X12's 1' on center, and the decking will be 1 1/4" T&G plywood.

The 2 vehicles we plan on parking in this area is a Chevy Silverado (approx 6,000 lbs), and a Ford Fusion (approx 4,500 lbs). I may also park my motorcycle (800 lbs) in this area too.

I would like to support the floor from underneath in the center with a steel I beam, and, if possible, have no support columns under the I beam.

The steel company needs to know the live load, dead load, and total load for the floor system so they can size the I beam.

How much are these 3 figures, or how do I calculate them?

Thank you.

Sincerely,

Rich

Answer
Hi Rich, the live load is how much weight the floor is expected to support plus and added percentage usually 20%.  The dead load is the total weight of the materials that make up the floor, the weight of the joists, the plywood, the drywall of the ceiling below etc. All of the loads are calculated per square foot.  Look up the weight of materials at the following website
( http://www.abe.psu.edu/extension/factsheets/h/H20.pdf)  add it all up and divide it by the total square footage of the floor system.  Do the same for your vehicles etc. for the live load. Then add the live load to the dead load for the total.  I suggest that you will need an engineer to sign off on the design for building permits so you might as well get one involved now to help with your final figures.  I hope this information helps, feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com