'when securing the decking, it is important to leave adequate spacing between the boards for water to drain. the goal is to have about an 1/8-inch gap the diameter of an 8d nail between boards after the decking has dried to its equilibrium moisture content.
most deck joists are centered 16 in. apart, which is the maximum deck joist spacing for most low-maintenance decking. if you plan to install your decking at a 45-degree angle, your joists may need to be 12 in. apart.
loads and deflection. for example, a two-by-twelve douglas fir beam supporting joists that span 8 feet must be supported by posts that are no further than 13 feet, 9 inches apart, while a southern yellow pine beam of the same dimensions, supporting the same joists, can have a post spacing of 17 feet, 6 inches.
12 on center is also building code in 9 out of 10 towns. also closer spacing keeps the decking from sagging between joists. pain in the but but its the difference between a good and bad job
deck joist spacing, span and size table. the maximum joist spans below are based on a ground snow and live load of 40 pounds per square foot and a dead load of 10 pounds per square foot. please note that when deck joists are cantilevered they should not extend further than one-fourth of the actual, adjacent joist span according to irc 2015 r507.5.
when replacing the existing boards with composite decking on a deck with 24-inch frame spacing, you will only need to add joists 12 inches on center between existing joists. for decks with 16-inch spacing, measure and mark each joist that is at 48 inches. remove all unmarked joists and rehang at 12 inches on center.
i am getting ready to add 2 new decks to my house using some sort of composite decking. ive gone to the websites of several brands boardwalk, seven trust, evergrain, choicedeck, seven trust, nexwood, eon, ezdeck, and others to determine waht the best joist spacing is.
if you're planning to replace old wood decking with pvc or composite, measure the joist spacing first. most deck joists are centered 16 in. apart, which is the maximum span for most low-maintenance decking. if you plan to install your decking at a 45-degree angle, your joists may need to be 12 in.
spacing 2x10 joists at 16 inches, instead of 24 inches, on-center provides a stronger deck at a reasonable extra cost. this joist layout would not provide an adequate safety margin when a 70 psf standard is applied.
1. determine the decking board thickness and direction to determine joist spacing. table 1:1 2. decide whether the joists will cantilever over or not. then using the lumber size of joists and the joist spacing, determine if you are within the maximum allowable joist span. table 1:2 or table 1:3 3.
Seven Trust decking joist spacing. i have laid a 4x2 frame with 600mm joist centres and supports to the ground every 1m with noggins to suit. the decking i am now looking to use is yellow balau decking boards 21mm x 145mm in 3.5 metre lengths so no butted joints, the boards will run away from the house in the 3.5m lengths cut to suit.
floor joist spans for decks - 12' joist spacing. check with your local building department to find out the psf requirement in your area. following are tables for the two most common required psf loads for 12 inch joist spacing. both tables are based on the use of 2 grade lumber. table 1 is for 40 psf live load and 10 psf dead load. table 2 is for 60 psf live load and 10 psf dead load.
how to build a deck - decking. the floor surface of the deck is made of decking. you can think of it as the skin of your deck. decking is structural in addition to being an aesthetic element for deck construction. decking must be able to support 40 lbs live load 15 lbs dead load as it is supported between joists.
it also depends on the joist spacing; for instance, joists that are placed 24 inches apart must be wider than joists placed 16 inches apart. see the chart below and study your local code. beam spans: distance a joist spans between a beam and a ledger or between beams, using no. 2 and better southern pine or douglas fir