The 2015 International Residential Code (IRC) came out last June and the section specifically covering decks (R507) is now up to 6 1/2 pages – the 2012 IRC only has 2 1/2 pages. Most of the new subsections will make prescriptive deck construction a lot simpler.
Even if your local jusisdiction is following a previous version of the IRC, you may find some of the new code subsections useful for designing and building decks. And most building officials will approve the use of new model code provisions even if they haven’t been adopted locally.
Here’s a list of the 2015 deck code additions:
- A new option for lateral load connections that can be installed entirely from the exterior.
- A joist span table for sizing joists and section figures, and language permitting overhangs up to 1/4 of the joist span.
- A deck beam span table for sizing beams based on the joist span and size of the beam.
- Post to footing subsection with figures and a post size table.
See other Build A Deck blog posts that cover each of these new deck code provisions in more detail.
- 750 lb. Lateral Load Connection – 2015 IRC
- MiTek / USP LTS19-TZ lateral load connector
- Simpson Strongtie DTT1Z lateral load connector
- Deck joist span table – Table R507.5 and illustrations
- Deck beam span table – Table R507.6 and illustrations
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All of this is great information and tells me a lot especially that my deck is out of code and considering that I want to redo my deck, I’ll have to get it up to specs. The one thing I still do not see, and maybe I overlooked it, is the size of the posts to support the beam and deck or anything regarding the size of the ledger board. As for the ledger, I’m generally of the idea that it’s hard to go too big, but could easily be too small. Any thoughts about the post size. I currently have 6x6’s and have not seen an 8x8 and have looked for another project.
Thanks