rafter spacing and sheathing

[Bwagner]

We are putting a roof on a home. When we removed the origional roof the raters have odd spacing. they are 50 inches apart. on top of the rafters they have horizontal 2x6's that are nailed on every two feet. They are true trusses not hand framed. We are going to sheet the roof and put on a new compostion roof. We sheet houses with skip sheathing all the time, but i want to make sure on how to do this. From looking at the code tables it looks like we may need to put two layers of t and g (3/4")

is that correct? or can we just sheet it and clip it?

thanks,
Matt Swanson

[Jerry Peck - Codeman]

[Jerry Peck - Codeman]

A correction/clarification:

You said "rafters" and I used the term "trusses" - regardless, 50 inch spacing is unusual ... especially with "rafters".

Now, if you are referring to heavy timber construction or old post and beam construction, then a spacing that wide or wider would not be uncommon (albeit 50 inch spacing is odd as it is not an evenly multiple number to work with - 100 inches (is not 8 feet), 150 inches (is not 12 feet), etc, and spacing are typically based on a larger number having been divided up for an easier working solution.

So that 50 inch "rafter" spacing is odd, and, yes, I would still recommend a structural engineer, just drop the 'truss engineer' part.