I’m looking to build a covered patio. It will be 13’ long and 35’ wide.

For the ledger I will be using 2x8s attached to the house with 5” lag screws. The rafters will also be 2x8s 16” oc. I have 6x6 posts for the front where I will be framing in a section that will be 11’ long with a post in each corner, a 12’ opening, then another 11’ framed in section with two 6x6 posts in each corner. I’m using 4x6 for beams going on top of the 6x6 posts using all Simpson brackets. Each beam is 12’ long.

The roof will have OSB on both sides and will be using cap sheet for the roofing.

Does this sound ok? I wanted to notch the 6x6s and attach the beams but the issue is the height of the ledger that will cause the opening to be lower. The walls will be 8’ tall and I was wanting the opening to be 8’ tall also.

Hopefully this makes sense.

  • Where do you live? Dec 18, 2023 at 4:40
  • I am in Phoenix Az Dec 18, 2023 at 4:41
  • 4×6 beams sound flimsy. Why not rearrange the material into a 2×12? It's about about two times as strong and 4 times as stiff. Without snow, you then have wind to design against. An 11 ft beam that presumably supports 13 ft joists still sounds flimsy. Your ledger probably needs some sort of tension ties to keep it tight to the house. You should check out the IRC's exterior deck details. Specifically, codes.iccsafe.org/content/IRC2021P2/…, although you might learn a lot from the whole exterior deck section (your cover is basically a deck).
    – popham
    Dec 18, 2023 at 7:21
  • If I used 2x12 which I wanted to originally for the beams, that will make the open section header too low. The ledger is 9.5’ tall. My home is a single story and I am not able to go higher. Using the 4x6 would allow me to have a 8’ opening and have the slope for the roof. Dec 18, 2023 at 7:31
  • 1
    A drawing of your building site & build plans would help far more than just some words. Additionally, since you're attaching this to the house, it becomes part of the structure and will need appropriate footings. You probably don't have a very deep frost line in Phoenix, but it'll still need some sort of footing...
    – FreeMan
    Dec 18, 2023 at 13:46

2 Answers 2


I don't have a concern about the joists being heavy enough. In fact, if the actual span is something less than 13 feet you may be fine with 2x6 rafters. Be sure to crown them up all upward.

Your beams aren't up to snuff, though. Firstly, no one in the modern framing world uses 4x6 beams except for swing sets and rustic timber structures. Your beam should usually be at least as tall as your joists. I'd guess double 2x10 for your span and load, but double 2x12 may be more appropriate. Crown them properly as well.

Popham is a better resource for the nerdy stuff. I'm just relating what I've accumulated over many years of building to the specs of engineers. I agree that you need expert approval of some sort, as the details matter for safety and longevity.


You'll need an engineer for this. Wind load is going to determine the design. Canopy wind loads fall under 30.11 from ASCE 7-16. Once you have a wind psf, then IRC tables can provide your framing sizes, where you could substitute 0.75(20psf)+0.75(0.6)(wind psf) for the tabulated snow psf.

My wild guess is that a 10 psf dead load plus 30 psf snow load under IRC rafter tables provides sufficient framing for your patio cover. 10 psf dead load plus 40 psf live load under IRC R507 should yield a conservative design.

You'll probably need a load path down to the foundation for resisting uplift, too. Typical deck details will get you 90% there (toe nails in joist hangers and notched post connections with 2 bolts each), but the post bases will probably need some tension detailing.

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