Joists at 12”o.c. Regardless of the method used, span and spacing depend on the type and grade of the wood, cantilever, beam size, height off the ground, footing size, and live load values. Figure 2. The boards and furnishings rest on a deck frame of joists supported by beams, ledger, posts, and footings – all are important. The distance of the beam from the ledger determines the deck joist span. Additionally, the inconsistent spacing will create an irregular pattern of fasteners that detracts from the visual look of the deck. As I’ve already mentioned, tables exist that allow deck builders to determine how far apart they can place deck support posts based on joist, beam, and support post size. Start at the center of the rail and work toward the … Deck joists, similar to those in any structure, determine the load a floor or deck framing can carry. The size and spacing of footings tie directly to the maximum spacing between posts of the beam they support. Each factor affects the span, the spacing, or both, as well as the placement of beams and support posts that make up the deck frame. Generally, the maximum joist spacing for boards running perpendicular to the joists is 16”o.c. They’ll be more than happy to answer your questions and give you a paper copy of your local building code. Free-standing decks don’t have a ledger. Uncovered Decks and Porches How to Use this Guide Provide two sets of plans, drawn to scale and complete the following (hint: use graph ... posts spaced apart (example: 4 x 4 posts spaced 8’ apart) ... post locations and spacing, joist and beam spans, and any other pertinent information not shown on the section drawing. On the other hand, as your joist length increases, so does the diameter of your footings that your deck support posts sit on. To make it simple, place your posts no further than 8’ apart. Span and spacing calculators, whether on-line or hand-held, use algorithms to identify the span based on wood type selection, joist size, and spacing. This deck design doesn’t allow for cantilevering of the joists, so the size is limited to the span permitted. Joists commonly are spaced at 12”, 16”, or 24” centers depending on the load the deck frame will carry and the size, type, and orientation of the deck boards. A beam of that size can span nearly 12’ while supporting 10’ joists. Minimum 36 ”at all points above the permitted handrail height. When I built my deck, one of the biggest questions I had was how far apart should I put my deck posts? JOIST SELECTION CHART Joist Size Maximum joist span between bearers at specified joist spacing 450mm 600mm 90 x 45mm 1.15M 1.00M 140 x 45mm 1.85M 1.60M 190 x 45mm 2.50M 2.15M or less spacing, and 2” planks are limited to 12”o.c. It provides a warm wood glow that many appreciate. Once you have your joist span, and pier spacing you can size each component of the deck using Tables 1 and 2 below. Once again, thanks for taking the time to read this guide. Beams must sit on top of deck support posts, using code-approved fasteners. Deck joists are planks laid on edge in a spaced pattern to which the deck boards are fastened. Lumber with no blemishes is rated select, clear, or #1 and is stronger and more expensive. Manufacturers of different composite decking products commonly include instructions with their products. The width, thickness, wood type, grade, and spacing influence the span a joist can bridge. A Joist Span calculator commonly identifies the maximum span and cantilever for dimensional lumber joists based on wood type, joist size, and spacing between joists. So to span 10-feet use a 2×8. The wood needs to be cleaned yearly and have a water-proof boost every other year, depending on your climate. Measure the distance between posts at two corners and divide by the distance allowed between posts. Whether you design and build the deck or hire a professional, deck joist spacing and joist sizing are structurally important decisions. STAIRS. If you can’t find your local building code online or just want to play around with calculations to envision what your deck support post layout might look like, then visit an online deck post spacing calculator. There are several methods for setting posts. Erecting and spacing beams to allow shorter spans means less expensive and more readily available timbers may be used. The last columns identify the spans for the beam at 12’ and 10’-6” with the cantilever. Round up to the nearest whole number, then subtract 1. Another rule of thumb is to layout fixtures in odd numbers (3, 5, 7, etc. If you live in a snow-belt and need to clear the deck, it’s easier to push in the direction of the boards than across them. There are tons of spacing charts available online, made available by various municipalities to help their constituents better understand how to properly space their deck support posts to ensure they pass inspection. On the other hand, you can always fabricate a larger deck beam and put your deck support posts further apart. The other deck, with 12’ joists, can have support posts at 7’6”, max. For those in Canada, many consider tables from Ontario and deck support post information found in tables from British Columbia are helpful. For commercial applications, joist spacing is 12”o.c. The distance between deck support posts depends on the type of wood species used and the size of the joist and beam. Having long joists is nice because, in theory, it could mean a shorter beam. The shape determines post and beam placement, spacing, and dimensions. for composite and 5/4 decking, and up to 24”o.c. A 2×6 yellow pine at 16”o.c. Tributary Load. It offers greater strength and allows joists to be spaced up to 24”o.c. The distances deck joists must span and their spacing influence the size and grade of the lumber, and vice versa. The IRC reflects proven construction techniques for wood decks using widely accepted conventional construction materials and practices. Adding a hot tub or spa to the deck will increase the live load and affect deck joist span and spacing. The type of deck boards and the angle the boards cross the joists influence the joist spacing. can span 9’-11” but that drops to 6’-8” with a cantilever. Incising weakens the wood slightly, so it often is rated for shorter distances. The joists are usually not visible, so using expensive premium timbers isn’t necessary as long as the beam structure is properly placed. We’ll also explore how they influence the strength and safety of a deck. There are several construction methods for installing deck joists. Hardscape and deck fixtures are generally spaced about five to seven feet apart, but there are numerous circumstances that force changes to that rule of thumb. spacing or greater. Deck joist spacing for composite decking is the same as that for 5/4” boards. The most confusing part about understanding how far apart to space your joists is understanding the chart that explains it. The cost difference between 2x8s and 2x10s is approximately $7.00 each. Medium Strength: Redwood, hemlock, and spruce will span almost as far. The frost line and snow load tables in Florida are different than Minnesota, so code has to take that into account, for example. Size and spacing depend upon the shape and size of the deck, the weight it needs to support (hot tub? when laid diagonally to joists, and 16”o.c. The most common grade used for joists and deck framing is #2, which has some knots but not enough to weaken it. 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