Self-Storage Building

Link

Link

http://www.cps.gov.on.ca/english/planmenu.htm

The minimum design is typically 5 pound per square foot dead load, plus 25 pound per square foot live load. I think 24 feet is beyond the reach of sawn lumber, even with the 1/3 stress increase for live load. (Deep TJI's might (barely) work in mild climates). The actual load requirements are a function of your climate (amount of snow and wind).

Now, if you didn't care about clear span and could put in a center beam, then this would be easy to do with ordinary lumber. Cut the span down to 12 feet and you have 1/8 the stress (and 1/16 of the deflection).

If you do want a clear span, go down to the local building supply place and order some 24 foot roof trusses. A 24 foot span is considered the "commodity span", and these are much cheaper than trusses even one foot longer or shorter. Get the walls up first, and the truss company will deliver the trusses atop your walls with their boom truck "for free".

"Live load" is the weight of people or objects assumed to be supported by the floor, floor/ceiling assembly, or roof. This includes a usual allotment of furniture, but one is expected to make adjustments for unusual situations (say for a room holding a piano collection).

For residential occupancies, "dwelling" rooms are figured at 40 pounds per square foot. Some codes allow for "sleeping areas" to be figured at 30 pounds per square foot. "Attics" with storage are usually figured at 20 pounds per square foot live load.

If your storage room is simply a partition wall, separating one part of a building from another, you should not need a thickened slab. If you (or someone down the road) plan to somehow support weight (beyond the weight of the wall itself) then you do. (This makes the wall a "bearing wall"). So floor joists spanning the room, or a ceiling atop it with at least 30 inches of clear space above, would justify additional support for the wall. (It is assumed that someone, someday, may store their rock collection on top of the ceiling, even if you don't plan to).

The thickened slab you propose should meet most codes for up to a 40 PSF live load above the ceiling, assuming that you have reasonable soils below the slab.

Scott

Anyhow, 24' slant is possible but certainl;y not practical, it will cost you more than buying trusses.

--->Paul