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Old 08-29-2012, 09:06 AM   #31
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Unsafe Deck?


Alright, I reviewed the American Wood Council's prescriptive wood deck construction guide.

Lets be clear. This is not the code. The information provided is a guide that is based on the organization's best understanding of the IRBC, and their suggestions that conform to this code.

Digging into why they don't like side loaded connections, this is the note provided in the commentary section.

Prohibiting attachment of the beam to the sides of the post with fasteners only (figure 9) ensures wood-to-wood bearing and avoids potential issues that could arise from using inappropriate (non-corrosion resistant) fasteners.

I disagree with this point of view. The idea that we solve code violations, by failing to utilize appropriate fasteners, by imposing new rules that require bearing of beams on columns is overkill.

Why not just hold people to using acceptable fasteners and then we wouldn't have to worry about secondary support?

12 to one half dozen to another in my mind, but notched posts at column locations is not a code requirement. I agree with the professional builders here that it provides a stronger connection, secondary means of safety, and a more solid deck. But it isn't a requirement by the code.

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Old 08-29-2012, 09:11 AM   #32
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Originally Posted by GBrackins View Post
I agree, side loaded connections can be designed, however the prescriptive nature of the International Residential Code does not allow this type of connection without it being designed by a professional engineer or in your case, an architect (see below). Myself I tend to provide guidance where applicable based upon the prescriptive requirements.
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Originally Posted by robertcdf View Post
True, however code will require you to get an engineer to approve this connection now. In a bolted situation the wood will fail before the bolt, and it will fail because it will get dry and crack more and more, and then it could fail in a catastrophic way. However if the beam is resting on top of the post... Well it's kind of hard for it to fail.

Got it.

I have signed off on many of these connection details with calcs and never had an issue. I guess I didn't realize it was because I provided back-up and sealed the docs.
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Old 08-29-2012, 09:21 AM   #33
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Some local AHJ or state building codes have amended the IRC. Such is the case in Massachusetts where R301.1.1 Alternative Provisions was amended to include the Prescriptive Residential Wood Deck Construction Guide thereby making it code.

I have used side loaded connections, and prior to the IRC it was pretty much standard construction in my area for attachment of beams to columns for residential decks. Since the adoption of the IRC ..... not so much

An architect or engineer's stamp trumps the prescriptive code .....
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Last edited by GBrackins; 08-29-2012 at 09:24 AM.
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Old 08-29-2012, 09:24 AM   #34
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The original poster could live where there are no codes and they just want to make the deck safer. If you are being forced to follow codes then you have no choice, but there is more than one way to fix this. Adding some hardware and wood will make this deck safer.
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Old 08-29-2012, 09:25 AM   #35
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Lot of good discussion here on the topic. Thanks to all for taking the time to post.

Here is some additional information on the deck that might be pertinent:

Rim and floor joists are 2x10, 16" O.C., spanning 10' from ledger board to rim joist.

The 6x6 posts are spaced 8' apart and are continuous from ground to where railing is attached.

If I go the route of using through-bolts where the rim joist is attached to the post, do you think I can safely/securely do so, given the presence of all the existing nailing? I'm thinking, specifically where the two rim joists butt together at the post. With all those nails, I'm wondering if the wood strength would be compromised by drilling holes for the bolts.

BTW, I've also arranged to have a contractor come out for a consultation.
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Old 08-29-2012, 09:40 AM   #36
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One thing you might want to do Mahogany is visit the local county inspectors or permit office and have a chat with them, as they should be able to give you some good advice on how to make the deck more sturdy (assuming you live somewhere that this is possible). Also, you didn't mention it, but does the deck feel bouncy at all or unstable, or did you simply know better?

Based on an 8' beam span and your joist span, I'd think you'd "need" at least 2 2x10's acting as your beam to meet the current code. As others said, there are definitely ways to do this that might not be super costly, but would definitely be a fair bit of work. One way to bring it upto the 2009 IRC would be to notch the posts to accept two 2x10's. Of course, this is no small task as you'd have to cut all the joists back several inches and temporarily support the joists while doing this. Also, the railing probably wouldn't be suitable any longer as the 6x6's would be notched considerably. It would be good to talk w/ a contractor, but also be wary as many seems to be unfamiliar w/ proper building codes themselves..

Last edited by NewHomeDIYGuy; 08-29-2012 at 09:42 AM.
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Old 08-29-2012, 07:15 PM   #37
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Unsafe Deck?


I've also seen these connection details used and I'm a lot more comfortable with them when they are INSIDE and in other protected environments. When wood is exposed to extreme UV, rain, heat, cold, etc it undergoes more stress than sitting in a climate controlled environment inside a building. It's not a fact that the bolt will fail, it's more about the framing material cracking, splitting, rotting and then failing at that connection point.

But it's cool, armchair quarterback and don't listen to guys who have extensive field knowledge based upon many years of personal experience that the books just don't show.
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Old 08-29-2012, 11:52 PM   #38
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Quote:
Originally Posted by robertcdf View Post
I've also seen these connection details used and I'm a lot more comfortable with them when they are INSIDE and in other protected environments. When wood is exposed to extreme UV, rain, heat, cold, etc it undergoes more stress than sitting in a climate controlled environment inside a building. It's not a fact that the bolt will fail, it's more about the framing material cracking, splitting, rotting and then failing at that connection point.

But it's cool, armchair quarterback and don't listen to guys who have extensive field knowledge based upon many years of personal experience that the books just don't show.
The issue with this connection type isn't based on wood degredation, but rather with incorrectly specified or installed fasteners per the authors description and narrative of the issue. Additionally, if wood is degraded and deteriorate to the point that bolted connections have nothing to grab onto, the connection didn't fail, the wood did. A wood failure such as this wouldn't be saved by notching and seating the rim joist.

As far as your last sentence. I won't be drawn into a argument with individuals who have a chip on their shoulder about design professionals vs. builders. Making assumptions that if one is educated by the book that they lack real world experience is common error. Some individuals decide to be on the other side of the plans after awhile and go on to earn a license.

Back to the topic.
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Old 08-30-2012, 02:47 AM   #39
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Originally Posted by Mahogany View Post
I'm posting a couple of pics of the situation. Thanks for any advice you can offer.
As a deck builder I can tell you that is definitely an unsafe deck and if it were my deck I would temp it up very cautiously and notch the post and add full bearing double 2x. If this is something you haven't done before I would get a professional.
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Old 08-30-2012, 08:25 AM   #40
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Unsafe Deck?


So why are folks so in adamant about a double rim joist? I completely understand the support column needs to be underneath the rim joist but why add a second 2x to the rim? What benefit is there other than stiffening up a little flex?
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Old 08-30-2012, 08:29 AM   #41
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Quote:
Originally Posted by jcarlilesiu View Post
The issue with this connection type isn't based on wood degredation, but rather with incorrectly specified or installed fasteners per the authors description and narrative of the issue. Additionally, if wood is degraded and deteriorate to the point that bolted connections have nothing to grab onto, the connection didn't fail, the wood did. A wood failure such as this wouldn't be saved by notching and seating the rim joist.

As far as your last sentence. I won't be drawn into a argument with individuals who have a chip on their shoulder about design professionals vs. builders. Making assumptions that if one is educated by the book that they lack real world experience is common error. Some individuals decide to be on the other side of the plans after awhile and go on to earn a license.

Back to the topic.
I don't recall you being the only person in this thread... You automatically assume I'm talking about you? Sounds to me like someone is sensitive to something.

If the wood splits where the bolt is going through you are correct it's not a failure of the STYLE of connection HOWEVER that split never would have occurred without that style of connection, therefore having the beam sit on the post would have PREVENTED that failure.
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Old 08-30-2012, 08:29 AM   #42
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So why are folks so in adamant about a double rim joist? I completely understand the support column needs to be underneath the rim joist but why add a second 2x to the rim? What benefit is there other than stiffening up a little flex?
Because a single 2x10 cannot act as a beam spanning 8' between posts.
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Old 08-30-2012, 08:37 AM   #43
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Originally Posted by robertcdf View Post
Because a single 2x10 cannot act as a beam spanning 8' between posts.
Why can't it work, just a purely theoretical question.. Would the beam bow over time and eventually fail? Just curious. I'm in the process of building a deck myself. I used 2 2x12's for beams, but I have one beam that spans almost 10'.
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Old 08-30-2012, 08:43 AM   #44
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But you are using (2) 2x12's correct?

Find me a span chart that shows a single 2x10 (or a single member 2x of any size) being used as a beam...
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Old 08-30-2012, 08:46 AM   #45
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Unsafe Deck?


OK, so being used as a beam is the problem. I agree with that 100%. If here were to simply add new support posts beneath the deck and install a girder supporting the deck resting atop the posts the single rim joist would be fine.

I just wanted to make sure the rim joist wasn't the issue, it was the fact it was being used as a support beam as well that was.

Thanks!

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