Construction Industry/Load capacity per psf

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Expert: - 8/1/2007


Question
I have built a 16'x18' room in a warehouse. I planned for a floor on top for lockers for the guys to keep personal items. I put 2x8x16' ceilling/floor Joyce in and a 5" HO I beam supported under it. I need to know the maxium weight per square foot it can bare. It must be posted on the room

Answer
David,
I suspect you should have asked the question before doing the work. I am not sure, by your description, that the layout will be acceptable by a building code.  

As for your question:  There are three load calculations that are considered.  
Top-live load is the load created by people, furniture, snow on roofs, etc.
Top-dead load is the actual weight of the material used to build the platform and
Bottom-dead load is the material installed as a ceiling.

In your case the top-live load should calculate at 40 psf (pounds per square foot), the top-dead load at 10 psf and the bottom-dead load at 5 psf (assuming a drywall ceiling)

The span for a 2"x8" floor joist, in order to carry a live load of 40psf, is 10 feet.  I am assuming the I beam you refer to is spanning the 18' dimension which would mean your joists are actually on an 8' span.  5" for an I beam is what concerns me.  It is small for such a span if it is not supported by at least one 3" column in the middle. And, that column should be on a pad footing. Also, did you install wood or metal bridging between the joists?  This is needed to prevent the joists from tipping and to stiffen the member.  You didn't specify the distance between joists and I recommend that they be no greater that 16" on center.

All that in place, you may post notice that the floor will support a live load of 40psf.  (That is suitable for what you describe but would not be adequate if you have machinery or very heavy concentrated loads on the floor.)  Some codes require that you post the three loads, i.e.
40/10/5 psf.  or 40/10/0 psf if you have no ceiling.

I hope this has been helpful.
Roger

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Roger Zona

Expertise

I am experienced in all types of construction: residential, industrial and commercial; single family, multi-family, mid-rise and high rise buildings (16 story office building) as well as remodeling, additions and tenant improvements. I can field most any question that relates to general construction. I have consulted with infrastructure (utility) contractors also and have a good general knowledge of underground utility construction for subdivisions and commercial projects.

Experience

After college, I began my career in the construction industry. I chose to become an apprentice Architect and 4 yrs later I opened my own architectural design firm. Six years later I moved to Florida to buy & develop land and build. I became a State of Florida Certified General Contractor and operated my business for 45 years. I built all types of residential and commercial buildings including warehouses, shopping centers, high rise apartments and office buildings and developed sites for other contractors. I retired and became a consultant to the construction industry. I maintain my license and continuing education requirements, operate a small construction company and write a weekly newspaper column for the Palm Beach Post (a Cox publication) with the byline "Ask The Contractor". I am the "technical editor" for a publisher of books that relate to home maintenance.

Organizations
Previously - NAHA Currently - FLCA (Florida Licensed Contractors Assoc.)

Publications
Palm Beach Post newspaper - weekly Q & A column Happy Herald monthly real estate publication - monthly column

Education/Credentials
Michigan State University University of Detroit BS in Engineering

Past/Present Clients
I built a home in Palm Beach for a member of the Pulitzer Family. I was responsible for the completion of a twin hi-rise condominium project for G.E. Credit. I was a partner in the successful development of a P.U.D. (Planned Urban Development) subdivision. I represented the largest home builder from France (Bati Service, S.A.) in the development of a subdivision and the design and construction of the homes.

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