BRACING - IRC 2012 - At-A-Glance
IMPORTANT DECK LEDGER RULES
LATERAL LOAD CONNECTIONS
These are newer guidelines that help secure the joist and deck to the main home. This idea was introduced in the 2009 IRC, but the hardware displayed below is NOT required, as there are other engineered options to accomplish similar results. The lateral load connector hardware is quite ingenious as it secures the deck to the main home framing. Some approved method of lateral load protection is required when the deck is NOT freestanding and the portion of the deck that touches the house is supported off the home. Check with your local building department for their requirements for your particular deck situation.
Before I share the code citation, look at this commentary from the May 2009 issue of Fine Homebuilding...
And if you never noticed the one code provision that’s been included in the IRC for years in section R502.2.2 that says: “Where supported by attachment to an exterior wall, decks shall be positively anchored to the primary structure and designed for both vertical and LATERAL loads as applicable” then you will when you look at the new section R502.2.2.3 Deck lateral load connection. There’s a new prescriptive lateral load connection option you can use to keep the deck from pulling away from the building. Even though you are not required to use the detail, it will most likely trigger the notion in your local building official's head that "Hey, I should enforce something." And unless you have an engineered alternative solution, your local inspector may require that you use the connection as detailed. LINK TO FINE HOMEBUILDING
The 2012 IRC deck lateral load connection citation below includes the IRC commentary...
PROPOSED CODE CHANGE
Exception: Design for lateral loads, and connectors in accordance with Section R507.3, shall not be required for decks that do not require guards in accordance with Section R312.1.1, provided that the deck ledger is connected to the band joist in accordance with Section R507.2.
This is actually a good example of how the codes get modified due to unintended consequences. This proposal shows the implementation of common sense by stating that the use of lateral load connections is overkill for decks that are not over 30” off the ground. The typical ledger attachments are more than adequate and added lateral load hardware are not needed. This also spells out to the AHJ the exception, since some might latch onto lateral load connections as their “Code of the Day” and require them everywhere. BUT, the unintended consequence is now going to be the perception that lateral load connector hardware is NOT needed on low decks, but MANDATORY on taller decks, which was not previously the case, as other engineered options were and are still acceptable.
FOR MORE LATERAL LOAD INFORMATION:
- See the Simpson Strong-Tie LATERAL LOAD TECHNICAL BULLETIN
- See also Professional Deck Builder's article LATERAL LOAD CONNECTIONS
Here is an image of the product
There are those that still wonder why they need to cut into existing finishes to make the interior portion of the lateral load connections. “Why can’t we just make the attachment the the rim board?”, they ask. M. Fournier wrote on the internet, in part...
“A reminder to those of you who mention not wanting to disturb finishes to get access to the framing I say if you are counting on the ledger and it's attachment to the house to support the load of your deck as well as resist any lateral loads you BETTER be opening up to at least inspect the framing unless you built that house you are making a dangerous assumption to assume that those that built it did it correctly or that it has not suffered any damage over the years since it was built to be sure it can support the loads you intend to put on it. If you do not want to do that then you are better off building a free standing deck, NEVER count on unknown existing structure to support anything with out first checking.
If you do not think a rim joist can be pulled away I have a few words of advice
Unless you know for certain how well a house was built to begin with don't take anything for granted. Sure it would be very hard, on a new house built to today's code to pull a properly nailed rim joist out of the structure if it was glued and proper nailed to 3/4 subfloor and then the bottom plate was then properly nailed though the subfloor into the rim joist as well but unless you built that house How do you know it was?...”
STILL MORE TO COME - RETURN FOR MORE GOOD INFORMATION