In North America, joist spacing for residential decks is 12″ to 16″ apart, or according to local building code. Most decks require 16″ spacing for the deck itself, with 12″ spacing used for special applications, such as stairs or commercial structures.
As a rule of thumb, most decks will require 16" on center joist spacing, which means there is 16" from the center of one joist to the other.
In general, the standard spacing for floor joists is 16 inches on center (OC) for 2x6 and 2x8 joists, and 24 inches OC for 2x10 and 2x12 joists. In other words, the centers of each joist are spaced either 16 inches or 24 inches apart from each other, measured from the center of one joist to the center of the next.
Here are some key considerations: 1. Span and Load Capacity: 2x6 Joists: Typically suitable for spans of up to 10-12 feet, depending on the load. They are often used for residential decks that will support lighter loads. 2x8 Joists: Can span further, generally up to 12-16 feet or more, depending on the load.
TimberTech's Advanced PVC Decking is designed to span up to 24″ on center. Deck joist spacing 12“ or 16“ on center is recommended for most materials, though wood decking and some manufactured materials can be installed with 24″ on-center spacing.
6, the allowable joist span for a 2x10 would be 11 feet 5 inches, with a maximum cantilever (taken from the “10” joist-back-span column) of 2 feet 6 inches, for a total span of 13 feet 11 inches. Even adding 2 1/2 inches for the ledger and half the hanger seat, the total maximum deck depth is 14 feet 1 1/2 inches.
For instance, a 2x6 redwood or cedar joist can span eight feet at a spacing of 16 inches. On the other hand, a 2x6, 16- or 18-gauge steel joist can span 16 feet, 4 inches if the spacing is 12 inches.
For most decking projects, two screws per joist are the rule, and you should choose screws based on your material—stainless steel for timber and specialized screws for composite decking. As you install, be sure to follow the spacing guidelines and take your time to ensure your screws are aligned properly.
FOOTINGS Must be large enough to prevent the soil from being loaded to more than 2,000 pounds per square foot, with the bottom 48" below finished grade. For example, a simple 12' x 16' deck would require three 12" sono tube footings.
Do Deck Joists Need to Be Treated? Pressure-treated lumber is ideal for deck framing. We also recommend using joist tape or a wood protectant to help shield cut ends from moisture damage.
A 2x6 floor joist can typically span up to 12 feet and 6 inches without support. However, the distance a joist can span depends on several factors, including the spacing of the joists and the type of wood used: Spacing: For example, a 2x6 redwood or cedar joist can span eight feet if spaced 16 inches apart.
Long joist spans and poorly planned structural layouts cause more sagging floor joists than anything. If the beams are spaced too far apart, the long floor joists are probably stressed and bowing under the weight of the home and gravity.
Deck joist spacing should never exceed 16″ on center (with the exception of MAX deck boards, which allow for maximum 24″ on center). For a more rigid feel, 12″ or less may be preferred. If adding additional framing, be sure to keep all boards level and in plane across the tops.
The distance a 2×6 can span is determined by the species, grade, location, use, load, and spacing. Based on building codes, a 2×6 can span anywhere from 2'-1” to 20'-8” depending on the affecting factors. Ceiling joists don't normally have the same load restrictions, and so can span greater distances.”
R507. 6.2 Deck Joist Lateral Restraint. Joist ends and bearing locations shall be provided with lateral resistance to prevent rotation. Where lateral restraint is provided by joist hangers or blocking between joists, their depth shall equal not less than 60 percent of the joist depth.
2x8 for joists will be fine, with 16" OC. Should use 2x10 for beams but 2x8 will be fine as well. If you are worried you can triple the 2x8 for the beams but double will be sufficient. You should put the beams at 7 and 14 feet out from the house, with the piers you should do 3 per beam with spacing of 1, 7, 13.
2x4 11'-6" 2x6 17'-0" 2x8 21'-8" 2x10 25'-7" 24" O.C.
Deck joist flashing tape is an affordable and effective way to protect your deck's wood substructure. 1. It helps prevent moisture penetration 2. Helps protect lumber from rot 3.
Screws are the superior choice for screwing down deck boards to the joists. The threading helps keep the attachment sound over years of weight and contact to which your deck will be subjected. One of the most important factors when using screws is that they won't creep up out of the holes like nails will.
Decking Material:
Softwood decking (cedar, pine): #8 or #9 gauge screw. Hardwood decking (redwood, teak): #9 to #10 gauge screw.
In truth, the answer is very simple. Lay deck boards so that the best-looking face is facing up! Wood is stable when its moisture content is held above 30%(fiber saturation point). As wood dries below 30% it shrinks.
This size has become popular for decks due to its balance of strength, weight, and affordability. The term “5/4” reflects the lumber industry's historical way of measuring thickness in quarters of an inch, a system that has stood the test of time.
The best timber for decking joists should be a kind that is resistant to moisture, insects, decay, or rot. Timbers like Cedar, Ironbark, Spotted Gum, and pressure-treated pines are good to use as decking joists. That said, if you have the budget, choose composite joists which will not rot, warp, decay or splinter.
24” OC should be ok with 2x material, 16” OC for 5/4 board and 12” is recommend for most composite material. A lot of other factors to consider as well so take anything unusual into account.