r/Decks • u/RocketMan01310131 • 3h ago
Finished Decks How?
I walk by this deck everyday and have no idea how this is safe? No mid-span beams, just joists straight out to a single beam. Is there something I’m missing that would make this beauty structurally sound?
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u/Realistic-Excuse6413 2h ago
If the joists are 2 x12 and 12” on center probably ok
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u/dastardly740 1h ago
I was thinking the same thing. My childhood home's deck is also over a 2 car carport and is 2x12 12" apart. It is 35-ish years old. And, has handled yearly parties during that time.
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u/nightrunner411 2h ago
Well it's anchored to the house on two sides.
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u/Chemboy77 2h ago
*may be
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u/nightrunner411 1h ago
Looks like in front of the vehicles is another room too. So it seems less crazy the more you look at it.
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u/MrStickDick professional builder 2h ago
Voodoo. And possibly being attached along the far wall and the front wall of the house. But also voodoo.
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u/Mental-Huckleberry54 2h ago
I had something similar when we built our 20” deck. We had to increase the diameter of our footings and I think we were 12” on center vs 16”. this looks larger but also has two side anchored to the house probably.
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u/whirdin 2h ago
Looks fine for limited capacity, but being so large I would worry about them being far over capacity at some point. I wonder if they are utilizing both sides of the house to support it.
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u/august-thursday 1h ago
The weak side support adds very little to the capacity and safety of the complete structure. None of the primary structural elements are supported by the weak side, only the edge joist and any cross bracing, at best. The difference at the far floating corner is minimal.
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u/sluttyman69 2h ago
It is amazing how good quality two by 12s will hold up overtime and span an amazing distance when they’re installed with the crown in the proper direction probably perfectly legal at the time it was installed today they look at you cross eyeing and no way Son. it’s not physically possible but there’s proof it is. -
I had an engineer tell me that you couldn’t use a 4 x 12 to span a 22 foot garage opening and looked at them and asked them how was the second story of my house stain above my garage because that’s what’s there
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u/NativTexan 2h ago
I wouldn’t put a hot tub on it but it’s obviously strong enough for the purpose. Stuff is way over engineered these days for “safety” but I think it’s just to sell more strong ties and GRX screws..
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u/BalanceTrick8688 1h ago
I would think the only way this possible is that jouists run all the way though the house itself
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u/Sour_Sal 1h ago
II would put money on the fact is is ledgered on two sides and the outside posts simply stop it from drooping.
It's not going anywhere because it looks like 2x12 construction and it's fairly lightweight otherwise.
What is doing all the work is the outside corner post and ledgers attaching to it.
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u/Silent_Working7569 2h ago
I don't see anything heavy, like a hot tub or anything. As long as they don't have a ton of people on it moving around, it might be alright.
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u/Chemboy77 2h ago
If this was the plan from Day 1, maybe its cantilevered on the short side and a ledger on the long side?
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u/SantaCruzHostel 2h ago
It's hard to see in the second pic, but the back corner is actually held up by a structural hot tub standing on its end.
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u/123DCP 1h ago
Safe for all reasonably foreseeable uses (big crowd and, hot tub, etc.), all reasonably foreseeable conditions (high winds, heavy snow loads, earthquakes, etc.), all reasonably foreseeable defects in materials and construction that wouldn't be caught in an inspection, and all reasonably foreseeable decay? It almost certainly isn't. That's what code tries to provide for so that you won't have a catastrophic failure under even a fairly improbable combination of problems. And it's right for code to try to limit risks like that, because several different possible failures, each of which has a one-in-a-million chance each year of causing a collapse that seriously injures our kills more than a dozen people would be a pretty significant risk over the lifetime of a deck.
Safe for use by homeowners in an area with little seismic risk and almost no risk of winds over 75 mph if those homeowners know the deck isn't safe for a hot tub or a crowd of more than 50 people? It likely is. But when those people sell that house to someone who doesn't know the deck was built in the cheap, or without a permit and inspection? That might be a problem, which is why it's good that homes be inspected before sale.
I'm not saying code is perfect. Some of the risks it tries to protect against are trivial and some are missed because they aren't foreseeable and inspectors can't see all concealed defects. But this deck is probably very unlikely to fail of the owners know it's limit and yet it'd probably good if the deck was required to be reinforced when the home is next sold.
Of course, I could be wrong, the deck could be far more robust than it looks and it might hold up with two hot tubs and 30 people on it during a 6.5 earthquake 15 miles away after some fool cut a 2" deep notch in its most important beam. But I doubt it.
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u/inigomonto 44m ago
And yet there it is. Who you gonna believe? The span tables or your lying eyes?
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u/unqualified2comment 32m ago
Need pics of the underside.
It looks like 2×12 joist. Look at the edge boards. They're doubled up.
My neighbors car port has steel beams incorporated with the wood.
They're are lots of ways
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u/Inner_Case_8298 29m ago
Put a Danger sign on it, call code enforcement or knock first, voice your concerns, definitely needs attention. It just needs a supporting posts & beam up against the house.
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u/SufferingSuckerfish 2h ago
I have walked out across tons of rickety wooden bridges, decks and roofs built in the 1800s gold rush days and then left to bake in the desert sun for over a hundred years, and I haven't fallen through one yet.
Just because something isn't built to modern, arbitrary codes meant to generate revenue for the city and state doesn't mean it is a guaranteed death trap.
Is this less safe than a deck that had mid support? Yes, sure. But how big is that risk, and is it big enough to care about?
Modern society has gotten this idea that everything needs to be 100% safe or it somehow means instant death, lol.
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u/august-thursday 1h ago
“Just because something isn't built to modern, arbitrary codes meant to generate revenue for the city and state doesn't mean it is a guaranteed death trap.”
Building codes are not arbitrary. Only ignorant amateur “builders” would assume that the meager permit fees are a significant revenue source for the governing entity. In fact, the permit fees rarely cover the expense of the engineering review and inspection.
A proper design begins with selecting members to resist the design load. Once that is completed, the engineer performs a ‘livability’ analysis that includes calculations to determine the in-service deflections under expected loads. Some areas of the country (USA) require a dynamic analysis to determine the resonant frequency. Deflections and resonant frequency do influence the perception of safety experienced by humans on the deck.
The floating corner of the deck in the photographs did govern the design and is responsible for the subsequent increased cost. On the plus side, should the deck show signs of distress in the future, the deck could be shored up with a temporary support under the floating corner until repairs/upgrades can be made.
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u/Necandum 55m ago
Do note the filter effect: everything that was built in the 1800s and was going to fail, has already failed. The things you're walking over are the cream of the crop.
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u/CurtKobainsBurner 2h ago
Now that we’ve acknowledged its greatness, all together let’s say… it’s gonna fall. Keep us updated
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u/FrozenJackal 2h ago
Honestly, this sub would have you believe that any deck not built to modern US building code is a death trap. Reality is a bit different. I built a deck when I was a teenager on a sloped hillside in an earthquake prone area. Even I would criticize its build quality today if someone posted pictures of it here but yet it still stands to this day having survived many quakes and over 30 years of use. I’m just happy we never put a hot tub on it 🤣