Deck Hangers Attached directly to Rim Board

[aseeng]

I saw this condition on a recent site visit where the contractor nailed the deck joist hangers thru the exterior OSB sheathing into the LSL rim board. They did not install the 2x ledger with lag screws per the plans. I understand there are issues with flashing and lateral pullout design has been addressed by steel beam tie backs as part of the architectural design. My question concerns the joist attachment itself. From a load transfer standpoint I'm not sure I see a problem as the rim board ultimately gets the load anyway, be it from the ledger or directly from the joist. I see reference to the ledger board all through the code but is it specifically prohibited to not have the ledger?

 

[XR250]

Flashing would be my biggest concern. Also, is the OSB just a 12" strip at the band or does it go up the wall? You may have to fasten that in additon to the hangers, otherwise it just acts as a 1/2" spacer that the nails must cantilever thru.

 

[aseeng]

OSB is continuous up the wall.

 

[DBronson]

aseeng:

As I understand the code, for a prescriptive design (ie not engineered) a ledger board would be required and would need to be fastened with the code listed fasteners. However, if you can demonstrate that the connections to the rim joist are adequate, then you should be good. I'm skeptical that the contractor can achieve a decent flashing job with that arrangement.

Regards,

DB

 

[BUGGAR]

"They did not install the 2x ledger with lag screws per the plans."

Need direction??

 

[Ron]

Check pullout and shear for nails in OSB and LVL as compared to solid lumber. I think you'll find them to be lower.

Also, fundamentally, failure to follow plans and specs is a building code violation under the IBC

 

[XR250]

@Ron;

Lag screws are not allowed in our area. Does the IBC allow those?

 

[Tmoose]

XR250 wrote - "Lag screws are not allowed in our area."

Hi XR250 - where are you located?

regards,

Dan T

 

[Ron]

XR250... My point was that nail values in OSB and LVL will likely be less than in dimensional lumber, so the hangers would not have the same capacity the way they are installed.

Why are lag screws/bolts not allowed in your area?

 

[XR250]

@Ron,

The reason I asked was that the original post said, "They did not install the 2x ledger with lag screws per the plans"
I believe they do not allow lags as anything larger than 3/8" technically cannot be used in a 1 1/2" band as their is a 4D min. requirement by the NDS.
Also, apparently, there has been some failures throughout the nation with bans attached with lags.
I typically just use structural screws now if I can't get a thru bolt in there.

 

[Ron]

You are not installing the lags into the top of the ledger, you're installing in the side into the primary structure. For that application, the 1-1/2" has no relevance other than to the length of the lag screw. Since the ledger is probably a 2x10 or 2x12, you have plenty of room to put lag screws into the side and engage the primary structure, even with a double row, staggered.

Given that, if you do not have a ledger and you are fastening the hangers through the flush side of OSB and into the LVL, I would check the nail capacity; however, as others have noted...this is a flashing issue that will come back to haunt everyone involved, you included, when (not if) the attachment fails from water intrusion issues.

As a professional you have a duty to bring such things to the attention of those who can decide on such matters. You have two things to point....a code violation for not following plans/specs and a flashing issue that violates Chapter 14 of the IBC (another code violation), assuming you are using the IBC. If not, there are comparable flashing requirements in other similar codes.

 

[XR250]

Huh;

If the band is a 2x10 or 2x12 and is 1 1/2" thick, how does that not violate the NDS's 4d min. penetration requirement for lags larger than 3/8"ø?

 

[Ron]

The lag screws are for attaching the ledger to the rim joist through the OSB. You will have lags that are significantly longer than the thickness of the ledger. For this you are concerned about lag screw capacity in the side of the OSB+LVL.

The penetration to which you refer is into the LVL, not the ledger.

 

[XR250]

I understand that Ron. However, you are still going into the face of a 1 1/2" member (if it dimensional lumber). The NDS requires at least 4D penetration into the member. You can use a 10" lag and it can stick thru 6", but you still cannot get more then 1 1/2" penetration into the band as it is only 1 1/2" thick.

 

[mike20793]

Simpson has hangers that can be installed over 1/2" sheathing. I doubt one of these hangers was used, but you could always check that. They have a technical bulletin with the models and subsequent loads. I have used them balconies on multi-level residential projects; they tend to be the higher capacity hangers (double shear).

 

[msquared48]

For the lags, pullout should not be an issue, only bearing. The tension from lateral load moment should be taken out with additional straps at the ends on the deck.

Mike McCann, PE, SE (WA)