The 2009 International Residential Code (IRC) has a number of big changes when it comes to framing decks.  If your state, county or town will be adopting the ’09 IRC you’d better take a look at a copy of the code before you get a code violation.

The changes are all related to how you connect the ledger to the building.  For one, there’s now a prescriptive chart for fastener patterns, no more ‘rule of thumb’ bolt or lag screw frequency.  You just match the depth of your deck to your fastener of choice (1/2 inch lag screw, 1/2 inch thru-bolt or 1/2 inch thru-bolt with stacked washer space) and you’re good to go.  But you are going to need a structural engineer if you want to bolt your deck ledger to anything but a 2x rim joist or a 1 inch thick Douglas Fir LVL rim.  This means you have to know how the floor is framed when adding a deck to an existing building.  Plus if the rim joist is concealed on the inside, you have to provide some sort of visual access for inspections – get out the hole saw….

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