The rule of thumb is 1 cleat should be responsible for every 1-1/2 sq./ft. of roof area.Therefore the formula to get the total number of cleats required:
Divide sq./ft. of the roof area by 1.5 = number of cleats for that roof.
Divide 216 by the width of your panel to determine cleat spacing.
(216 is the number of square inches per 1-1/2 sq./ft.)
example: panel width 18 in. divide 216 by 18 = cleat spacing every 12 in.
a 12 inch wide panel should have cleats every 18 inches
an 18 inch wide panel should have cleats every 12 inches
a 24 inch wide panel should have cleats every 9 inches
Around the perimeter is more critical!
The amount of fasteners used at the ridge, eaves and rakes should be doubled from the formula above. This means that if you have a cleat every 12 inches up the roof then you should have two within 6 inches of each other at the eave, the ridge, and every 6 inches along the rake.
Remember that all perimeter details must be closed so no air can get under the panels.
View our cleat testing reports here