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Re: Residential Deck Live Load

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bcainse(--nospam--at) wrote:

I think the higher code load was primarily intended for balconies that are cantilevered from the main structure due to the issue of lack of redundancy of the cantilever and the tendency for deterioration at the connection to the main structure. However, any sizable deck will attract a significant number of people at some point in its life and will have a higher likelihood of seeing the design live load than most floors will.
Bill Cain, SE
Berkeley CA
-----Original Message-----
From: Domenic DeAngelo <domdean(--nospam--at)>
To: seaint(--nospam--at)
Sent: Mon, 11 Apr 2005 16:40:43 -0400
Subject: Re: Residential Deck Live Load

Under item 27, I am not sure why the Code would state the load of 40 psf for all other areas except balconies and decks unless the intent is for decks and balconies to have a different load but I would agree that the code is rather ambiguous about it. I would always use 60 psf and note it on the drawings.

The loads, for me, depend on the potential use of the structure. I've never used less than 40 for live, and usually end up designing for L/600 (which is almost always in the 65-100psf range) for serviceability - there's very little to stiffen or deaden a deck, and wobbly decks make people nervous. Often, it's the snow load that controls a portion of the deck, and sets the joist depth for the whole deck. Even with a ground snow load of 25 or 30 psf, if you run drifting checks and sliding surcharge you can easily get local loads above 60psf.

Finally, if I know the area is one frequented by students (I live in a college town), or that has a high rental possibility, I go with 100psf or 200PLF vertical on the outside edge (think football players sitting shoulder to shoulder on the railing). Students seem to find ways to fall off decks/balconies without any "help" from a failing structure.

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