Single Span Vs Double Span Metal Deck Roof

Of course single span is conservative.

Single span vs double span metal deck roof.

A multi span element has continuity across any interior supports and can be more efficient with regard to considerations such as bending s. Two spans less conservative. A 2 2x10 can span 10 feet and so on. Load values for single span and double spans are to be reduced.

Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. With simple single span joists that are overlapped at the center beam or girder the reactions are equal at each end of the joists. Three spans was considered representative of any additional number of spans say 4 5 6 or more. Design of double span roof beams in houses office buidlings schools and other structures.

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. Metal decking plans call for joists to be 24 inches apart so a double span deck plank is at least 48 inches long and a triple span deck plank is at. The use of only 1 2 or 3 span conditions for steel decking is a legacy from pre software times. A double 2x12 beam can span 12 feet.

The numbers in gray indicate the distance between the support posts. When supporting joists that span 12 feet with no overhang beyond the beam a double ply beam can span in feet a value equal to its depth in inches. In order to understand exactly what is metal deck used for you first need to understand a few basic principles of how metal deck works. Single span construction refers to a beam or slab which is simply supported assumed pinned at its ends.

The result is that you can use smaller sized stock be it conventional lumber or i joists for multiple span continuous joists than with simple single span joists. Double span decking uses surface material that is long enough to bridge the gap between two joists hence the term double triple span decking uses surface material that spans three joists. Also known as roof deck non composite floor deck composite floor deck metal deck decking or just deck. Steel deck is a cold formed steel panel usually used as a structural platform to form a roof or floor.

Dimensional lumber deck beam span chart. If uncoated form deck is used deduct the weight of the slab from the allowable superimposed uniform loads.