jar546 said:
This is the problem with the IRC. We have known that the DCA6 is wet service but I am still trying to connect it to the IRC legally so that we can use it for enforcement. We strongly recommend they use it but can't force it unless someone can show me how it legally connects into the IRC.
1) You can build something using prescriptive methods in the IRC, or an alternative means and method
2) Alternatives are engineering or testing
3) There is no prescriptive means to build a deck in the IRC, so a builder must go the "alternative" route.
4) There are no pre-tested complete deck assemblies, so engineering is what's left.
5) The Building Official has the authority to review alternatives to determine if they are "equivalent" to the IRC.
6) "Engineering" does not have to mean a signed and sealed drawing for each site, it can be pre-engineered information from "approved" sources.
7) The publishers of the DCA6 are the AWC.
8) The AWC writes the NDS, the bible for wood frame construction and referenced from the IRC
9) The AWC is considered a reputable source of engineering and the BO "approves" it's use as an alternative.
10) The Building Official politely tells the permit applicant that they can use the DCA 6 in lieu of expensive job specific engineering.
It's all in how you present it. It's not that you're FORCING them to use the DCA 6...that's negative and pushy. It's that you're LETTING them use the DCA 6 instead of paying for an engineer. How nice of you.
You can't install an elevator track using the IRC because there are no prescriptive provisions addressing it. You can't install joists in a wet-use environment using the IRC because there is no prescriptive provisions addressing it. What you are up against is that though for all of time (technically) decks should have been engineered, they have never been. Our culture seems to ignore decks when it comes to following the actual path the IRC lays out. You wouldn't have a problem asking for that engineer for the residential elevator...but the deck...that's tough. I too cannot demand engineering for every deck in my jurisdiction, as it's not the culture. However, I can certainly expect that they be built with some kind of validity. If you approach it this way, you'll be thanked for LETTING them use the DCA 6.
As for getting this fixed in the IRC...
I have been working with the NAHB, AWC, CLMA, NADRA, CCICC, VBCOA, SST, OMG, SMA, and many other interested professionals working to produce quality, prescriptive deck provisions for the 2015 IRC. Wet-use tables for joists and beams being a large focus. There are a variety of opinions, ideas and proposals related to decks this year.
Take a look at RB-264 and RB-268. Both include wet-use span tables proposed for the 2015 IRC.