span entries are listed for 2×6 through 2×12 joists and 12 in., 16 in., and 24 in. on-center spacing. the illustrations one for cantilever joists and one for flush rim-beam hung joists point out where joist span measurements are taken from the saddle of the ledger mounted joist hanger to the center
in general terms, joists spaced 16 inches on center can span 1.5 times in feet their depth in inches. a 2x8 up to 12 feet; 2x10 to 15 feet and 2x12 to 18 feet. the larger the deck, the larger the joists. 2x6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards.
refer to the decking span table to determine what is the maximum distance that your chosen decking can span between joists. for example 2x6 materials can usually span 24 without any noticeable deflection and still support a significant load.
your deck will look better and youll avoid the frustration of trying to splice the decking over joists. a splice board will also require extra framing. do it the same way you would for the perimeter boards one extra joist and a 2×6 on its side between the outside joist and the extra joist .
the cantilever overhang can be 1/4 the joist length, but again i would keep that to 2'-6 max. for 2x8. deck loading has a tendency for the people to gather at the railing. deck loading has a tendency for the people to gather at the railing.
what is the safe spacing of 2×6 deck joists to support a 3500 dead load of a sp. i would double up the joist in that area and also add double joist in between them to 12 oc also add a double 2×8 beam underneath that area to break that 10 ft span in half .then im sure it will be good to go .
following are tables for the two most common required psf loads for 16 inch joist spacing. all of the tables are based on the use of 2 grade lumber. table 3 is for 40 psf live load and 10 psf dead load on 16 inch joist centers. table 4 is for 60 psf live load and 10 psf dead load on 16 inch joist centers.
re: deck joist size i use all 2x6's for joist max span is 7'. the strength of a deck is in the post and footings. it has nothing to do with joist span. long joist span allow for way too much flexing of the wood due to severe climate and humidity changes. decks require a bunch of post and beams. those who hang decks off of houses have no foresight.
the joist span indicates that 2x6s at 24 o.c. would be adequate for this span. for beam 1, use a joist length of 13, 6 7 and a post spacing of 9. the beam table indicates that the beam may be two 2x10s or two 2x12s, depending on the wood used. for beam 2, use a joist length of 7 and post spacing of 9.
beam span chart table. building codes for residential decks only require 40 psf. the longer the joist, the more area of deck the joist supports, and thus the beam supports. for pressure-preservative-treated southern pine no. 2 grade, there is a method that can be used for estimating beam spans for a preliminary design.
a 2x6 will span less than a 2x8 and so on. i am calculating the need for 32 pier blocks for a 16x16 deck. that seems show more i am building a floating, ground level deck in my back yard. all i am reading is that deck blocks cannot be more than 5ft apart, regardless of the joist size.
if you use 5/4 decking, joists must be no farther apart than 16 inches. decking made of 2x4s or 2x6s can span up to 24 inches. if you will run decking at an angle, you may need to put the joists closer together; know your local codes.
when building a house or even a deck, it is important to confirm you have the correct joist sizes, spans and spacing before you get started. while most residential construction uses 2x8 joists with 16 inch spacing, there are many other factors you need to consider when determining the proper joist span length.
in other words, when you put weight on the deck, the joist won't bend. the usual solution for dealing with undersized joists is to use more of them, spaced closer together. so, for example, instead of 16' spacing with 6' joist, you may have to go to 12' spacing with a 4' joist.
aligned deck joist with min 1800 lb. capacity each, installed in accordance with mfr's instructions. the through bolts and washers shall be centered on the guard posts and spaced as shown in detail 1/s05. joist size rim joist deck joist guard post fasten rim joist to end of each joist with 3 10d nails or 10x3' wood screws r507.5.1
well, my 2x6 joists are spaced the maximum recommended 16 inches on-center on the new deck and 12 inches on-center on the refurbished one. although the joists span about 6 inches farther on the former than on the latter and add a cantilever, this still sets up an easy, if unscientific, comparison.