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Lateral load connectors

N

NH09

Silver Member
Joined
Sep 11, 2010
Messages
153
Location
New Hampshire
I was wondering how other jurisdictions are enforcing section R502.2.2.3 - Lateral load connectors. Initially we were requiring that all decks have at least 2 lateral load connectors, but after further research and a rather vague code interpretation from the ICC we determined that they would not be required in all cases. The only time we require them now is when the lagging requirements of section R502.2.2.1 cannot be met. Any thoughts?
 
I don't believe they are required when there is other provision for lateral as the wording is "shall be permitted to be in accordance with Figure R502.2.2.3", so that diagram is just one way of providing the lateral support required under 502.2.2
 
I'm thinking that because figure R502.2.2.3 shows the lags AND the tension devices they're discounting the ability of the joist hangers to provide lateral load support. While I agree with Yankee's comment about Fig 502.2.2.3 being only one way to accomplish the lateral load support, I doubt that you could just omit the tension devices in favor of the lags. The concerns addressed in the foot notes of Table 502.2.2.1 seem to imply that the lags are more to provide vertical shear rather than pull out.

NH09,

Would you be willing to post the vague interpretation you got from the ICC?

Bill
 
The tension device keeps the deck from pulling away from the building. The joist hangers are not going to be effective in resisting this tension.

Unless the deck is braced by some other means this connection is essential.
 
Sure Bill - Here it is:

QUESTION: My question is when is a lateral load connector required? In section R502.2.2 Decks, it is stated that "decks shall be positively anchored...for lateral loads" Does this mean that the only option is a connector like the one in figure R502.2.2.3, or that the lag bolts will suffice as lateral load connectors. Does the seismic or wind zone matter when requiring one of these connectors? Do any factors come into play when requiring lateral load connectors, such as height or a deck connected to the primary structure on two walls? This is really more than one question, but there seem to be many interpretations on this code section and I want to make sure I am enforcing it correctly.

ANSWER: Decks that are supported by the primary structure, in order to satisfy R502.2.2 with respect to both vertical and lateral loads, are permitted to be connected with lag bolts. The must be as prescribed by Sections R502.2.2.1.1 and Table R502.2.2.1. The seismic, wind or height, as design factors for the proposed deck, are not issues in this case. Outside of these prescriptive parameters, accepted engineering practices are permitted.

Maybe I'm being harsh by saying this is vague, but it seems to say that if you can accomplish the lagging required in R502.2.2.1 then the lateral load connectors are not required - simple enough. But I would think that when the lagging requirements cannot be met, then more than 2 lateral load connectors would be required to secure the deck to the primary structure, especially on a large deck. I wonder how we are supposed to determine these additional connections (lags, pins, etc.).
 
ICC said: "ANSWER: Decks that are supported by the primary structure, in order to satisfy R502.2.2 with respect to both vertical and lateral loads, are permitted to be connected with lag bolts. The must be as prescribed by Sections R502.2.2.1.1 and Table R502.2.2.1. The seismic, wind or height, as design factors for the proposed deck, are not issues in this case. Outside of these prescriptive parameters, accepted engineering practices are permitted."

That's just plain Gibberish! If this was the real skinny why did they draw in the tension devices at all? I think the whole tension requirement is bogus. While I've repaired several decks that failed in shear or pull away because the ledgers were just nailed on. I've never seen the joists pull out of the hangers.

The requirement for lags is a good addition. The tension members are unnecessary piece of over engineering that will add significantly to the cost of any deck.

IMHO

Bill
 
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I did not mean to imply that the lags, joist hangers or bolts were suppling the lateral load resistance. I don't believe that to be the case.

I can think of two other common ways 1.) when the deck has two sides against the house and 2.) when the deck is supplied with diagonal bracing.

There probably are other traditional ways of supplying the lateral load resistance
 
There are a lot of different conditions that come into play, such as Yankee said about 2 sides being anchored to the house. It would be nice if the ICC could at least come up with some triggering factors for requiring the lateral load connectors IE: only 1 side anchored to the house, a certain height above grade, more than xx square feet etc. I also have a problem with the "hold down devices shall be provided in not less than two locations per deck" requirement - theres a big difference in the weight of a six foot deck versus a forty foot deck, not to mention the amount of people you can fit on the larger deck.
 
You need something other than the lag bolts for a lateral connection. The lag may hold the ledger to the building but the deck joists hangers are not effective in holding the joists to the ledger.

The need for this tie is more critical when you can experience high wind or earthquake loading but you still need some form of connection to deal with more mundane loads.

More than two lateral ties would be appropriate for larger decks but when they tried to implement this as a proscriptive provisions they had to simplify it and as a result made it less safe.

What the detail in the IRC does not address is the case when the floor joists are parallel to the exterior wall.

These provisions suffer from the fact that they are attempting to write proscriptive provisions that address many variations. In addition
 
Hi Mark,

"What the detail in the IRC does not address is the case when the floor joists are parallel to the exterior wall."

You're right they missed that one entirely, however in that case at least each piece of decking is, or should be, fastened to the ledger.

Bill
 
I found this comment by an author of some book about the code

"When researching for my book Deck Construction Based on the 2009 International Residential Code, I often spoke with the International Code Council’s (ICC’s) technical staff regarding this new figure. They agreed that this detail is not intended for every deck built under the IRC, but only for those that require lateral load resistance greater than the band-joist-to-floor-system connections provide. Of course, that isn’t necessarily easy to quantify."

He also made comments about joists being parallel to the walls.

Since he claimed to speak with the technical staff, I would have expected him to give more guidance.

As an engineer I would ignore the entire issue as there is not enough information to indicate a standard to design to.
 
George wrote: "As an engineer I would ignore the entire issue as there is not enough information to indicate a standard to design to."

I'm with you George.

If'n it ain't broke, don't fix it!

Sure would be good to nail this one down before I end up on the receiving end of a correction notice.

Bill
 
around here, it sounds like builders are going to start doing free standing decks and no longer attach them... since the decks are usually built at the end of the job, no one wants to remove ceilings to install these devices... (but I think they are a good idea for attached decks).
 
I also searched the internet and found a website devoted exclusively to decks that had this discussion. One interesting additional note they had in explaining the requirement for the connectors was this, "Historically the bolted connection of the ledger board to the house rim was supposed to resist all the vertical shear forces and lateral loads that would pull the deck away from the house. The new code was developed to prevent the house rim from ripping away from the house by anchoring the deck to the house floor system"
 
peach said:
around here, it sounds like builders are going to start doing free standing decks and no longer attach them... since the decks are usually built at the end of the job, no one wants to remove ceilings to install these devices... (but I think they are a good idea for attached decks).
Click to expand...
Mmmm, , have they found out yet that they will need to excavate to the bottom of the house footing to place piers for the free standing deck : ) ?
 
Yup, on our present job the backfill is open at the moment and I'll drop 6x6's down to the bottom on PT wood footings and run a couple of horizontals and diagonals below grade to hold it all in place during backfill. This house has open web floor trusses which would have complicated attachment further. This also allows me to run the joists and decking the desired direction.
 
Can you say Huge Waste of money? How about diverted attention to real issues?

All of us have been alerted about this or that party where several/numerous folks were injured when a deck parted company from the main structure. I doubt any body can document such a failure to anything more than nails in pull out or failure because of deterioration of the deck framing itself.

Bill
 
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I wouldn't be too worried about pullout of lag bolts in lumber rim joists, as long as the subfloor is nailed to the rim. I'd be more concerned about pullout with the OSB rims that are used with I-joists.
 
In the field, very often there is a small strip of plywood under the wall at one rim thanks to modular 4' dimensions and 47.5" T&G subfloor. I know what you're supposed to do but it isn't often done that way. Is the connection of sole plate to rim sufficient?
 
By the way, can anyone tell me where those 2 tension devices are to be located? The code just says "Hold-down tension devices shall be installed in not less than two locations per deck."
 
Just a little update, I resubmitted my question (with some changes) regarding lateral load connectors to the ICC yesterday:

QUESTION: I had asked in June about when a lateral load connector was required, and received this answer: Decks that are supported by the primary structure, in order to satisfy R502.2.2 with respect to both vertical and lateral loads, are permitted to be connected with lag bolts. The must be as prescribed by Sections R502.2.2.1.1 and Table R502.2.2.1. The seismic, wind or height, as design factors for the proposed deck, are not issues in this case. Outside of these prescriptive parameters, accepted engineering practices are permitted. To ensure that I am interpreting this correctly, if the ledger fastening detailed in table R502.2.2.1 can be accomplished, then no lateral load connector is required. If it cannot, I would guess that two lateral load connectors would not be enough to support the ledger - what determines the addtional fastening neccesary? and would any other fastener (hilti pin for example) meet the lateral load connector requirement?

ANSWER:please re-phrase your question, it is not clear what it is you are asking. Provide a detail sketch if you feel it would be helpful.

This may take a while...
 
NH09 ---

I suspect you are asking the ICC to practice engineering. They seem reluctant to do so. That is proper.

So if the ICC guy is an engineer licensed in one state, can he give advice in another state and claim he is not practicing engineering ?
 
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