Timberframe Porch sheathing ideas

[wishin4snow]

Hello. New to the forum.

I am going to add a timberframe porch on the front of my house. One option for my rafter spacing is 41.5" c-2-c and only 3 rafters. My other option is approx. 27" c-2-c and 4 rafters. I am afraid that the smaller c-2-c is going to look a little two busy for the large beams.

If I go with the larger spacing, I need to use a 2x as my sheathing to keep to code and handle the roof loads. I thought about getting 2x6 cedar and ship lapping it. Then just adding some plywood on top for the shingles.

The 2x6 cedar is not cheap. I was wondering if you guys had any other ideas.

[Don P]

For code the minimum Fb, bending strength, is also specified, calling for stronger wood as the span and load increases. See the footnotes... and now that I'm looking at it, no snow load specified, code can start getting funny above 50 psf, other than that those are mighty low minimums.

I've used yellow pine and white pine T&G,, notice it does spec T&G not shiplap for that application.
Check the larger number on the roof plywood, the 2 numbers stamped on a sheet of ply are the allowable floor and roof spans. If the larger number is 42 or greater you're golden no matter what you do underneath, the wood is just for pretty then. That can factor in if the BO requires grading on the sheathing. Pull up, I feel a rant coming on  :D



 

I think you are fine with any of those species and many many more at 41.5" o.c. (on center, that's how you'll see it written on plans).