Location - do they need to support a huge depth of snow on occasions, for instance? What is the angle of the dangle, so to speak?

Local standards? Local building regulations? What did the local planning office approve at outline planning consent stage?

Local practices - what do other buildings in the area do?

First, you need to know the total roof area in square feet (ft^2). You must take into account the roof slopes, if any, in determining this value.

Secondly, you need to know the square footage of each panel (ft^2) and deduct the appropriate area for overlaps with adjacent sheets to figure out the NET AREA......then you must divide the total roof area by the sheet Net Area....presto whalla the minimum required number of roofing sheets. Don't forget to include a "bump up" figure to the total number of sheets to account for material waste, because the roofing sheets must be cut in the field....typically this can range from 3% to 10%, depending on the layout and the accuracy of the roofing guys.

This may help.

They are available for rent from LynDoor™Industries Divine the Answer Division at This site.

lyn, does the Wicked Witch of the West come with it?

Nope. She and Toto ran away together to Never Land.

Probably to visit those damn Smurfs....

LOL

The Smurfs are dead. They must be somewhere else.

The Right Place: U.S. Declares War on Smurfs, Hundreds Dead in ...