Below we’ll take a look at some of the main considerations when asking how far apart should deck posts be. - Beam splices are recommended to occur over posts or support only. It then determines the total load from each tributary area based on the design load of your deck. Since we need to know the inches, we multiply 20’ x 12” = 240”. However, if your deck will include a hot tub or roof, you must support that weight with additional footings. This value must not be greater than the bearing capacity of the soil. Determine your desired expansion gap and enter into deck calculator above. If your deck is slightly out of square (different widths), calculate results for both widths, and set out each end to suit. The pier size is in the intersecting box of the row that corresponds with your joist span and the column that corresponds with your pier spacing. If your deck is slightly out of square (different widths), calculate results for both widths, and set out each end to suit. The future is … A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on. Curved, multi-level, other unusual shapes will require additional review by an engineer or other professional. Remember to take post spacing into consideration as well. Use the 2018 IRC to size deck beams and calculate beam span. Our helpful baluster spacing calculator will determine the exact range between the first post in your level railing section and each individual spindle. Please adjust post spacing and / or beam spacing to reduce the load on the footings. These values didn’t change in the 2018 version of the IRC. Most city inspectors carry a 4-inch ball with them to test the spacing. For pressure-preservative-treated southern pine no. For furniture and people, use 40 psf (pounds per square foot), and structural materials or dead load, add 15 psf. Width of Boards (feet): Necessary to determine lineal feet. Getting Started. Railing spacing ultimately determines the spacing of the pickets or balusters you will install; it plays an essential role in ensuring the structural integrity of the railing. The lengths of each side of a deck often vary. The size of the deck directly affects the spacing of the support posts. As a result, the post spacings for a railing will vary as will the length of the railing section that fits between each post. Ideal deck post spacing is 8 feet or less. Learn how to use different methods to calculate spacing. ... joist hangers and joist support posts that raise the actual deck. Footing larger than 24” is required. Once you have your joist span, and pier spacing you can size each component of the deck using Table 1 below 3. 2 grade, there is a method that can be used for estimating beam spans for a preliminary design. Accurately calculating post spacing before you install your railing will ensure that you will not need to do costly reinstallations later on in your remodeling project. It also depends on the joist spacing. Even though we have based the calculations on the IRC, you must always check with local building codes to ensure there are no variances. U.S. building code requires support posts for the rail structure to be no further apart than 6 feet on a deck with 4×4’ deck rail posts and no more than 8 feet apart for decks with 6×6’ deck rail posts. While a 16-foot-by-16-foot backyard deck for recreational purposes, such as an outdoor kitchen and general lounging, may only require deck posts spaced every 7 feet, a larger deck may require that the spacing be narrowed down to within 5 feet. Spacing is completely dependent on the size of the deck. If you are planning on installing a hot tub or porch on top of your deck, you will usually need more footings and posts to support the additional loads. © 2004-2014 By Rich Bergman, The Titan post anchor is the most advanced hidden wood post anchoring system of its kind. Directory ? Inch or Metric. The American Wood Council (AWC) has an online calculator that can be used to calculate the size and grade of joist needed for a given joist span, on-center spacing, live load and dead load. Subtract the width of each post in your railing system from the total length. The other side wall posts need: Your project will need: The current design of your deck requires a footing larger than 24" diameter. If it is, you must increase the size of the footing to spread the weight out over a greater surface area or increase the number of footings. Is not responsible for inaccurate data entry resulting in product failure due overloading... 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