How do I build a Freestanding Deck?

[Ben Grunow]

Here in Ct the footings go 42" deep and I am sure that is true for NJ.

I would avoid burying posts in concrete and use a post base (http://www.strongtie.com/products/co...A-ABE-ABU.html) set over an anchor bolt cast in the concrete which keeps the wood away from the water. Local lumber yard in stock.

Joists could all be 2x8 and if you add a cross brace each way from each corner post (4x4 is fine) you might not need to attach to the house. I would make a perimeter of doubles that are bolted to the posts with 3/8" galv bolts and even notch one of the doubles into the post.

44" above ground requires a rail (anything over 30") so plan for one as a 44" fall is not fun.

[Peter Stahl]

Ben,

Thanks for the reply. We only have to go 30" in NJ. We don't get as cold down here.

[Rob Russell]

Mike, What is a impervious surface area and how you calculate that and the live loads? Thanks for the reply. Nice drawing, what did you do it with?

Impervious surface area is ground area that you cover with something that's impervious to rain and effectively creates run off. That increases the amount of water that other parts of the ground have to handle. For example, if you decided to add a large, 3-car parking area off of your driveway and that part of the yard has a gentle slope down to your neighbor's yard, you just sent that whole area's worth of rainwater down to their yard. I believe that the impervious area also figures into septic system leach field calculations.

Live load is the amount of weight you'd put on the deck per square foot. It's interesting that they want you to calculate the live load. In CT, the live load requirement for decks like Mike's building is 60 lbs/sq ft. As a comparison, standard house floors are typically framed to a 40 lb/sq ft live load standard. The reason for the additional weight-carrying requirement on decks is that people have outdoor parties and really pack decks with bodies. There have been deck failures in CT where people died, so they put in the more stringent load requirement.

[Peter Stahl]

Impervious surface area is ground area that you cover with something that's impervious to rain and effectively creates run off. That increases the amount of water that other parts of the ground have to handle. For example, if you decided to add a large, 3-car parking area off of your driveway and that part of the yard has a gentle slope down to your neighbor's yard, you just sent that whole area's worth of rainwater down to their yard. I believe that the impervious area also figures into septic system leach field calculations.

Live load is the amount of weight you'd put on the deck per square foot. It's interesting that they want you to calculate the live load. In CT, the live load requirement for decks like Mike's building is 60 lbs/sq ft. As a comparison, standard house floors are typically framed to a 40 lb/sq ft live load standard. The reason for the additional weight-carrying requirement on decks is that people have outdoor parties and really pack decks with bodies. There have been deck failures in CT where people died, so they put in the more stringent load requirement.

Thanks Rob. I would guess the higher it gets the tougher they are. I've seen several on the news that failed and the weren't attached to the build very well.