The answer is TWO(2)!
Since covering more than two spans does not increase the capacity of the structural metal roof deck, you might consider some of the practical advantages of using shorter sheets (for example, 10 to 15 foot rather than 20 to 30 foot) when determining the lengths to purchase.
Shorter sheets are:
1. Easier to transport.
2. Easier to maneuver on site and lift onto the structural supports.
3. Lighter weight and easier to lift by hand.
And, if you are going to get very technical, shorter sheets may also provide greater diaphragm capacity since more butted end laps will result in more fasteners. WARNING: While multi-span conditions typically allow for the most efficient steel floor deck, single span conditions usually reduce the capacity of your floor deck. Please refer to the table below to see the allowable distances that various roof decks can safely span when covering one or two spans.
Feel free to call D-MAC at any one of our 5 locations and we’ll be happy to help you choose the right lengths for your job.