Saturday, December 30, 2006

Snow Load on Decks

Snow Load on Decks

Logic in Building Decks is a relative thing.

photo by Jenzug (click for flickr site)
Think about it this way. You construct a home with 2x8 joists typically—you can nearly get away with 2x6 at times. Generally a deck needs to support slightly more “live load” than the interior of a house so the minimum joist size should be 2x8 – 16” o.c. You know that if you live in Southern California you are not likely to see that much snow—maybe the odd wildfire so see flame retardant coatings. You won’t need the structural reinforcement like they will need in Denver this month.

Some building departments will specify more strength in decks for snow load—but not all. Many just defer to the building department’s minimum standards-or apparently in rural Tennessee, there's just no rules.

Joist and Beam Spans must be reduced, footing sizes increased and joists should also be increased by at least 2” in size in areas where decks will need to support 4’ of snow. The connection to the house should be no less than ½” carriage bolts through the rim joists of the home on second level decks.

We built a deck on Georgian Bay where we were told the owner shovels the snow off the roof and on to the deck when it gets deep. This means up to 4 tons of snow on a deck platform from time to time. I helped him put a 10’ deep pile on the deck one day. 50 footings beneath a 600 square foot deck—but here we are 8 years later with a nice level deck.


No comments: