Floor joist carport framing

Im at a home that decided to use floor joists to frame the carport. We do occasionally get larger snow loads up to 3 feet in depth. The span is 16’ from house to beam.

While the joists are covered pretty much with paint they are still on the exterior of the home. I also came at any for of fasteners making an attachment of the joist to the ledger on the house and the hangers are for a 2x6.

Would your allow this on your inspection??




Well, the hangers are wrong. You can start with that.

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This is one manufacturer who says dry use application only (page 10 highlight)

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I would call it out as a material defect. There is no way that passed code. There is no sheathing (decking) either, just bare metal on what appears to be a very low slope roof. Metal roofing should not be used on anything less than 4:12 slope and should have sheathing underneath. You put three feet of snow on that and the metal will deform, then it starts to leak, then the “rafters” get wet and there goes their strength. It will collapse, it is just a matter of time. It is likely that the whole carport roof needs to be redone ($$).

Great points Brian. Here in GA the sheathing is not an issue, climate region is something to consider. But the OP is in Oregon and I would suspect snow load is applicable.

Other than the wrong hangers and missing nails on the uplift hangers, and maybe ledger attachment, I don’t see a problem with this carport roof. Corrugated metal can be installed on skip sheathing even in snow country with the proper spacing and a minimum of 3/12 pitch.
No different than a covered porch which also allows LVLs.

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A rule of thumb is snow weighs about 20 lbs per cubic foot. If said carport roof is 16’x10’, that is 160 square feet x 20 lbs x 3 feet thick (possible) = 9,600 lbs. That is equivalent of an Ford F-250 carrying an extra 2,000 lbs of sheetrock in the bed. I think the design you depicted would be fine for rain and perhaps light snow, but would be inadequate in heavy winter snow region.

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I am from Norther Maine originally, so I know how much metal roofing on skip sheathing can carry and how it performs under harsh conditions. It will slide off before it gets that thick and if it does it only weighs 7 lbs. +/-.

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The weight of snow can vary as much as the weight of “Yo Momma”

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I guess the point of contention then is the slope. I say, 4:12 is minimum (based upon InterNACHI’s training). You say, 3:12 is fine. The roof in question though looked flatter than either of those. BTW, 7 lbs is for probably light, fluffy, freshly laid-snow. I live in Northern CA, near the Oregon border, we had 10 inches of icy, wet, snow here a few years back that complete wrecked havoc, thousands of tree limbs and trees collapsed.

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The I-Joist at the outer edge is exposed to the weather and should be covered.

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The roof is so flat i don’t see it sliding off without the use of a roof rake.

This carport brought back memories of a house my wife and I looked at buying years ago. Some one had added a carport onto the house and ALL of the framing was floor joists, the roof, the walls, the header over the front fo the carport every was joists. It blew my mind.

HOLY CRAP I just found that it was a permitted addition. I have no idea if it was altered from original but here are docs from the county file.


There you go. But there is a lot of missing information on that sketch.

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I checked the Redmond Building Department website. The snow load may be only 15 psf from what I was reading. Pretty light snow requirements. Still, metal roofs are not intended for low slopes.

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In my opinion the biggest issue is the super undersized hangers. The I-joists can take the snow load, but those hangers should extend all the way up to the top flange. Simpson makes a special hanger for them. The height not only ensures enough nails for proper resistance to downward force, but also helps prevent potential rotation. As soon as that heavy snow load hits that roof those current hangers are in serious risk of failure.
Here’s a guide:

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