How far span can WRC 2x6 be placed as a pergola rafter/roof? Would be using 5 posts 6x6, 3 in front and 2 at back (connecting to an existing pergola), 4 beams 2x10x18, and need to know if the 2x6 can span over a 13 ft space with no additional support in the middle. These will over hang by 1.5 feet on each side making the 2x6 total length of 16ft. And will have 2x2 on top.

  • Not sure what a "WRC 2x6" is, but a normal SPF (Spruce, Pine, Fir i.e. whatever was cheapest from the loggers that day) 2x6 should be able to span 13' on edge since it's not carrying a load other than itself. That said, editing your post to include a drawing would be quite helpful.
    – FreeMan
    Commented May 20, 2020 at 15:24
  • I'm going to guess WRC = Western Red Cedar
    – Jason S.
    Commented Oct 4, 2021 at 16:39

1 Answer 1


Simpson Strong-Tie just created a pergola designer software last week. You can access it by creating an account at the link below.

Use this as a tool to check your framing sizes and spacing. If you can't select the member size you want, it's because that member size is not strong enough for the spans that you've specified.

It also shows you the connections you need and gives you a detailed report of all the material quantities you need. This is a perfect step to take before your trip to the hardware store.


  • This is quite interesting. You may want to edit your post to indicate or disavow any affiliation with the company lest your post get flagged as spam.
    – FreeMan
    Commented May 20, 2020 at 17:55
  • I see about 4 pergola questions a week on here. It's not spam, I'm providing a solution to a consistent problem. The software does the structural engineering for you and it's free.
    – represton
    Commented May 20, 2020 at 18:03
  • I didn't imply it was spam - listing your affiliation (or lack thereof) with a company you're linking to is a generally accepted practice at all SE sites, and "spam" is question closing/answer deleting option, so it's a concern. I did note that it's an interesting link and, if I were looking to build a pergola, it's one I would definitely use!
    – FreeMan
    Commented May 20, 2020 at 18:13

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