August 21, 2013 – Glenn Mathewson, NADRA Technical Advisor
How many hold-down anchors does it take to build a deck?
The development of the 2015 IRC is halfway through, and there’s likely going to be some new regulations for the construction industry to adjust to. For the decking industry, there’s lobbying working to create new building codes around specific product lines. We’ve already seen the costly results of including “permitted” details in the code depicting specific products. The lateral load anchor detail, that was published this way in the 2009 IRC, is quickly read as “required” by many building departments. Now, as new research is revealing that ledgers fair quite well without lateral anchors, there is a proposal seeking to “permit” the use of anchors on every guard post in the 2015 IRC. Will history be repeated and this also be read as “required”?
Proposals like this risk turning a standards document into something that looks more like a product catalog. More importantly, this lobbying, if successful, adds significant time and cost to deck installations in an increasingly competitive industry, while at the same time limiting design options and architectural freedom.
There’s a lot on the table this year in the development of the 2015 IRC. NADRA has submitted a public comment modification that reveals new information about ledger connection performance and seeks to remove the 1500 lb. lateral-load anchor detail from the IRC. At the same time, NADRA is fighting against proposal 268 that seeks to include new requirements for guard construction, complete with pictures of specific hardware.
LATERAL LOAD REQUIREMENTS-RB263
Proposal 263 seeks to include an exception to the lateral-load anchor for decks that are less than 30” above grade. While sensible, an exception to something merely “permitted” does not make much sense, and implies that what is permitted is actually required.
With new and exciting test results from Washington State University, NADRA’s public comment to RB263 attempts to remove the lateral-load anchor not only for low-level decks, but completely from the IRC. It turns out…people can only generate so much lateral load, and lag screwed ledgers can resist a whole lot more…four times more, and the test was stopped before the ledger ever failed. With a force four times greater than humans could generate, deflecting the deck 17 inches to the side, ripping the joists down the center…the ledger with nothing but lag screws held. The rim joist in the house held. The necessity of a 1500 lb. anchor clearly serves questionable value.
Does this detail belong as a minimum standard of deck construction now that the performance of a lag-screwed deck ledger is known to be quite sufficient?
Read Full Article HERE
See RB 268 details HERE
GIVING VOICE TO NADRA MEMBERS
If the issues of increased costs, inflexible design, and heavy-handed industry regulation with no material benefit matters to you, consider joining me at the code hearing in Atlantic City NJ on October 3 and 4th. Your presence, your voice, your attention and your passion will make a difference…after all…it is YOUR industry. Stand up and fight for it, but don’t do it alone. If you want to know more or get more involved, please contact me at glennmathewson@nadra.org. Together we can bring truth and insight to the development of the building codes.
