I want a very open Pergola roof. Can you leave the roof slats off?
I don’t want any top stringers, and on the spacing of the top boards, I’d like them to be 12″ or even wider apart. [Florida customer inquiring about a large pergola that will require a local permit.]
The different levels of a pergola roof are important structural elements.
The top stringers—what we call roof slats—are important structural elements. They are notched into each rafter below to make the super-strong “web” design of our pergola roofs. Without any of the 2×2 roof slats, I think you’ll have difficulty getting the permits approved unless we make some other structural adjustments. For example, you’ll have to place metal ties at each juncture between the rafters and the roof support timbers.
The roof support timbers are precisely that—they are the horizontal 2×6’s that are notched into each side of the posts and they hold the rafters that sit atop and perpendicular to them. Each rafter is notched into the roof support timbers below it, but to really strengthen the pergola roof to resist high storm winds in Florida, I’d recommend keeping at least some of the 2×2 roof slats above them.
If you’d like to have 12″ on center rafters, we can design the structural details in a couple ways. For example, if you don’t mind some “stringers” (roof slats), we can place them either 24″ or 36″ on center to just serve as extra strengthening without creating too busy of a structure. Or, if you really do not want any roof slats in the design, we can then place metal “l” brackets atop the roof support timbers between each rafter that tie to each side of each rafter. It will barely be visible from below and should be fine for the county permit also.
