I'm building my first timber frame, a small uninsulated summer cabin with 2 porches. The frame is common purlin and the roof decking will be 2" x 8" planks (100 lb snow load plus steel roofing over planks). The roof slope is 12/12 for the cabin and 3/12 for porches. Wind speed of 100 mph is anticipated. I'm not sure whether to nail or screw the decking to the purlins nor what kind of nails or screws and how many to use. I'd love some suggestions.