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I'm re-planking my deck and shoring up some of the substructure while I'm in there. The beams are side-mounted to the posts like this (from dca 6):

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This is obviously non-ideal, but is impractical to replace. I'm spot-checking the existing lag bolts and am finding some surface rust (not bad after 30 years), so in an abundance of caution I'm going to replace them with new ones.

Galvanized is what appear to be recommended, with stainless steel being preferred if you have the budget. However, what about the Hillman Deck Plus lag line? The only information I can find on them is their own marketing material claiming they are 2x more corrosion resistant than galvanized. Is this legit? Or should I stick with Galvanized or stainless steel?

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I don't know how they do their calculations about how long the coating lasts, but I have used some of their coated fasteners in the past and they are high quality. I would guess that the coating lasts at least as long as galvanized, so the idea that it lasts two times longer could maybe be accurate.

An added plus is that the coating is pretty smooth compared to galvanized, and less friction is a good thing when you're driving a bunch of them.

On the other hand, if you're replacing fasteners that have lasted 30 years...even new fasteners that last just as long start to get into the area of being somebody else's problem three decades from now.

It appears the the most likely point of failure is the wood, not the fasteners. Over time the wood beams can split and crack so the bolts/screws don't have much to hold on to. I'd also check out the posts and beams to make sure the wood is going to last as long as the new fasteners while you're in there. That may be the quickest failure.

I believe that's why the current codes specify that the beams have something to "sit" on instead of just being held on to the side of the posts with fasteners.

  • That’s a common misconception: as you say: “...the current codes specify that beams have something to sit on instead of just being held on to the side of the posts with fasteners”. That’s not true. Actually, the Code says, “Connections for wood members shall be designed with the appropriate methodology.” It does not say beams must sit on posts or metal connectors must be used. However, there is one exception: Type IV Construction (Heavy Timber Construction). (See ICC 2304.9.1) – Lee Sam Aug 29 at 22:28
  • Thats why I posted the comment with the Code reference. When it’s said over and over again, everyone starts to believe it... – Lee Sam Aug 30 at 0:55
  • @LeeSam 2304.9.1 doesn't seem to be particularly relevant here, but I think the confusion on this might stem from 2308.4.2.3. Further research tends to make me think that you are mistaken. awc.org/pdf/codes-standards/publications/dca/… Everything I read says that the beams need to have a bearing surface and not rely on the fasteners alone. Perhaps your part of the world is different. – Greg Nickoloff Aug 30 at 2:29
  • I see, but 2308.4.2.3 is under 2308.4: Floor Framing. I started at 2308 Conventional Light Framing and 2308.1.2: Connections and Fasteners, which refers to 2304.9. (This is hard) – Lee Sam Aug 30 at 2:33
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This video shows retrofit steel plate fasteners to strengthen the connections you have (at 3 min): connection of beam to post

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    Thanks for referencing the 3 minute mark. He’s actually saying it’s not good engineering practices and not compatible with the code in some parts of the country, which may be true for Type IV Heavy Timber Construction. For Type V Construction (standard light framing and residential framing) it is Code approved, but the Building Official May want to see your calculations. I admit, it’s easier to show the allowable loads from a Simpson catalogue rather than work the formulas longhand... – Lee Sam Aug 29 at 22:40

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