4x8 ledger size for patio cover?

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Old 07-26-13, 01:28 PM
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4x8 ledger size for patio cover?

I'm planning to build a patio cover and one of my options for joist/rafter is 4x6. I'd like to use the Simpson OHU46-SDS3 hanger for the joists, but this would require a ledger at least 3" thick for the SDS3 screws. I'm considering using a 4x8 ledger, and wondering if anyone sees any problem with this size, as far as the thickness of the ledger. The 4x8 ledger would be bolted to a double 2x12 that is part of the house framing.
 
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Old 07-26-13, 04:53 PM
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Why such heavy members? Certainly not for snow load in NM. If you just want the look of heavy timber framing, why not consider using conventional 2x framing members and then build them out with rough-sawn sheathing?
 
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Old 07-26-13, 06:16 PM
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I have checked the numbers with either 2x6 @16 or 4x6 @32 and either would work with Doug-Fir #2 (the span is only about 10ft). It's an exposed ceiling and I plan to use 1x6 tongue&groove for the roof decking, so I think the 4x6 @32 would look better. I'm using dead load of 10 and snow load of 20 (per the city).

I have an alternate design I've been working on, with the 4x6 joists bearing on top of the 4x6 ledger. I'd attach the joists to the ledger with 8" TimberLOKs. How about that? The slope is only going to be 1/2:12 and I could put a thin wedge under the joist to make it bear evenly, if needed. I've attached a pic of this sort of joist-ledger set up.

Edit: Note that the pic looks like it has rough 2x8 joists so you couldn't bolt through the top, but that should not be a problem with a 4x6.
 
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Old 07-26-13, 06:48 PM
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Wow--you must live in Corrales, where the retro-Southwest Pueblo look is "in." Or at least it was when I lived in Four Hills. Looks like you'll be spending more on fancy, carved columns than you will on the roof structure.

Your plan should work, especially since the loading is so light. I agree with using wider joist spacing and heavier members--it's going to look very nice. Have you considered adding some fancy scroll-work on the ends of the front beam? The square ends look out of place with everything else having the carved look.
 
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Old 07-26-13, 11:39 PM
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No I'm on the west side. That cover was built by a local unlicensed builder who does a lot of them around here (probably mostly out of the city and mostly without permit). I was just using the photo to illustrate the joist-on-ledger set up. The timber used for the cover in that photo is from Wholesale Timber in Bernalillo, and it's ungraded, rough Ponderosa Pine. I was planning on using dimensional doug-fir #2 lumber because I need the strength to make the calculations work for the joists and beam.

(1) 4x6 x 14' ledger
(6) 4x6 x 11' joists (10' span and 1' cantilever/overhang)
(1) 6x8 x 14' beam (11' clear span with 1-6 cantilever/overhang on each end)
(2) 6x6 x 7' posts
I do not plan to use corbels.

Now I have to check to see if I can meet the bolt pattern requirements in the IRC with a 5 1/2 high ledger. Of course these are for deck ledgers and not patio covers, but I want to be ready if the inspector thinks it should meet that.
 
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Old 07-27-13, 07:22 PM
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May want to double-check on using 3/4" (at 32"oc) rather than 2x for sheathing; New Mexico Building Codes

Chapter 23 - Wood

Gary
 
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Old 07-27-13, 09:27 PM
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Gary in WA - I'm not sure what you mean.
 
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