In my plans I am going to have a deck that is 12' x 12'. What size of floor joists should I use? I was possibly planning on putting a beam under the deck approximately 8' from the house. Configured this way there would be about 4' overhanging the outside of the beam. Is this OK? There will also be another deck tied to the one corner away from the house that will be approximately 10' x 10'. What special provisions do I need to tie these two together? I am more interested in the structural part as far as beam requirements and such. This deck will be about 24" off the ground. Also would it be structurally sound if I put a 2"x8" beam about 2 foot in on each in end of the 10'x10' deck to basically make it "free standing" as not to make it depend on the other deck for support?

 

gphusker,

How large of a joist you need is determined by how much it will be spanning, and how much of a load you have to build the deck to. A 4' cantelever is too much, no matter how large your joists are!! Dimensional lumber cantelevers 24", MAXIMUM!

In a 30 or 40 lb. snow load, you'll need 2 beams if the deck is ledgered to the house -- 3 if it's free-standing. This will allow you to use 2X6's for the joists, with no more than a 24" cantelever. (This assumes that the joists are #2 or better D.F. Different species of wood have different span capabilities.)

Need to know what kind of wood you'll be using, TOO!

 

So on my deck that is 12'x12' i should be ok if I put a beam 6' out from the house (where it will be legered) and one at 11' from the house.

 

That SHOULD be fine -- but check with your local bldg. dept. to make sure.

90% of the country is in an area with a 40 lb. or less snow load. But you haven't said anything to tell me that you are in that 90%!!

 

I live in nebraska

 

I don't want to be difficult here, but what's your snow load?? (I've never been to Nebraska!!) And while you at the building dept. finding out, ask about the frost level too. That will determine how deep you have to dig the footings!

 

The beam should be at least a double 2X10 with 2X8 joists. You could go with a single beam at 10 feet and have a 2 foot overhang (cantilever). This will be within code, and probably what a builder would do for you. There will be some bounce. Not much, but some. For super sturdy, you could put a beam at 5 and another at 10. To split the diference, you could use a single beam at 10 and use double 2X12's for the beam and 2X10's for the joists. Though you may not have enough height for that. Any of these will work with a two foot cantilever. If you have enough room under the deck, you might want to consider the single beam with the bigger lumber.