The remainder of this answer is a huge estimate based on lots of assumptions. Solid blocking over beams should be mandatory for decks. Bolt the posts to the inside of the rim joists. The tributary area is the portion of a deck supported by each deck post. per square foot. The weight of a simple roof over the deck is taken into account when using the tributary area method. Posts shall bear on footings in accordance with Section R403 and Figure R507.8.1. In simple terms, the tributary area is equal half the length of the beam on each side of the post multiplied by half the joist length to the next support plus the full length of the joist cantilevered past the support beam. code for nailing they will still check, may warp and will shrink at the splices which allows moisture to get trapped with dirt promoting the compromise of the beams over time. Ideal deck post spacing is 8 feet or less. Typically I'll use the ABAz with a 1/2 anchor bolt. Pole Barn / Post Frame. post and the edge of the deck = 2’) and half the distance to post #2 (half of 8’ = 4’). The weight of a simple roof over the deck is taken into account when using the tributary area method. This is 6’ of width and 7’ of projection. If the deck is going to be built near grade, contractors may feel comfortable opting for the smaller post sizes. As a practical exercise we will choose a deck that is 10 metres long and 6 metres wide. Design / Build, Website Design by Owner California decks built up and solid beam size tables and post size table. These are the beam size tables I use from the UBC code I find they still work well, I laid them out so they are easier to read and I found them better than the interior IRC table or the new deck prescriptive. In many cases, a 4- by 4-inch post is more than adequate, but if there is any doubt, going with the 6-inch post will meet all local building requirements. I prefer the adjustable 1" stand-off bases for decks above 30" I also keep my piers a min. I'll use the PCz post caps (left) if I have a condition on a slope with possible lateral movement or a heavy load with a large joist over a longer span. A larger beam can span a greater distance, requiring fewer but larger footings. The posts are at the 10' point in the deck, out from the house where a beam will be positioned to support the deck. My calculations came up with 15 3/4 in. There is no minimum span, and maximum spans can reach up to 15’. Where to position posts in deck footings. Posts shall be restrained to prevent lateral displacement at the bottom support. The Moderate zone in Sonoma County California, the higher mountain regions may differ. Always refer to your local building codes or a structural engineer this is how we build our decks, Deck footing & pier sizing for California, Deck connections for California's #4 earthquake zone. Typically I use the ACz post caps (right) for most decks, they handle the loads well  and are easier to work with placing the heavy beams. One of the key design factors is knowing how to calculate the post size that you will need to use to support the weight of your deck and the weight of the roof covering the deck. Crown Molding, Finishing Carpenter Deck two – 12 x 12 feet R507.8.1 Deck Post to Deck Footing. The distance between deck support posts depends on the type of wood species used and the size of the joist and beam. Step 3 Secure the Posts. Both  are adjustable the ABUz post base (left)  uses a 5/8 anchor bolt Determine what size deck beam you need based on your support post spacing, as well as the proper concrete footing diameter, with our beam span calculator at Decks.com. The size of the deck directly affects the spacing of the support posts. Spacing is completely dependent on the size of the deck. This is called the tributary load. Standard rail height is 36 to 42 inches; posts will need to be 10 inches longer. As a general rule, if the support posts are spaced no more than 10 feet on center, all you will need to use are 4- by 4-inch posts. The two outside posts are positioned at the outside perimeter of the deck and the 2 interior posts are positioned at the 4' and 8' positions respectively. Tables for the minimum joist spans in California's moderate climate regions, How we build a closed in riser stair for decks with a skirt for solid railings, Deck stair total rise table with calculations for riser heights and number of treads, Alter Eagle Our load area is 10 x 12 = 120 feet and according to the chart, we need 6-by-6 posts regardless of how high the deck is. Deck post sizes - 40 psf Live, 10 psf Dead: Height (ft) Load Area (sq. per square foot and a live load of 40 lbs. Conversion Bases allow Deck Lights to be mounted on a variety different post sizes. Measure and mark out the deck area using pegs and string. Summary - the post size seems questionable. A comparison of the footing sizes I calculated for the example deck resting on 1500 psf soil in the Sizing Deck Footings article and DCA 6 Table B3 shows an almost identical result. Beyond that amount, it becomes very difficult to meet the safety requirements. Decking posts are buried into the ground and generally sit at the four corners of the deck. Common post sizes include 4x4 posts, 6x6 posts, and 4x6 posts. Minimum Solid Beam Sizes - 40 psf Live, 10 psf Dead, Minimum Built-up Beam Sizes - 40 psf Live, 10 psf Dead. The advantage of using one of the deck designer programs is that most of them allow you to indicate the state where you live. Click for a larger images Maximum spacing of posts is 72 inches on center. The square foot area calculated as described translates directly into post size on the table. Tip: When digging deck footings, I always allow a minimum width of 400mm. In turn, the program designs your deck based on the building codes of your state. Decks building tutorials and design tables, The frequently asked questions on how to build decks for Northern California ft)= beam spacing x post spacing : 48: 72: 96: 120: 144: up to 6: 4x4: 4x4: 6x6: 6x6: 6x6: up to 8: 6x6: 6x6: 6x6: 6x6: 6x6: Vertical loads figured as concentric along axis. footing. If you have to use a built-up I suggest placing a flashing cap or membrane that won't break down and not use the ardox (threaded nail) as prescribed but use sds screws or thru-bolts. For a total of 6’ Therefore the tributary area of Footing #1 = 6’ x 7’ or 42 square feet. We live in the beautiful wine country of Northern California. Two reasons; first, it’s easier to dig; second, the wider deck footing provides enough room for me to move the post around in the deck footing while maintaining the minimum 100mm clearance around the deck post. Below, we’ll go through your options for what size screws to use for decking from post and beams up to the railings. diameter center footing size and Table B3 calls for a 16 in. Build a deck that will last for years to come by properly installing deck posts. After you found the true measurement of your post width, finding your perfect post cap opening size for your deck or fence post is a breeze.The ideal fence or deck post opening size is between 1/16 to 1/8 of an inch larger than the width of your post. It depends very much on your soil type. Mason County Checklist item #56 and #69 additional wood and fastener. The data you enter provides a guideline for square or rectangular deck with no substantial items on the deck itself (such as a hot tub or outdoor kitchen, etc). Setting a post is the foundational step for many projects, including building a fence or a deck. Setting the posts for your deck requires careful work, but it can also be exciting because the posts are the first visible sign that your deck is going up. In order to calculate your own floor load width you will need an idea of the size of deck that you want to build. There are several ways to set deck posts; we recommend attaching the posts to concrete footers above the ground. This will help you visualize the deck’s support system once constructed. I put the built-up beam span table below but I would very rarely use a built-up beam in an exterior application where they are exposed to the moisture conditions like a deck. A new table in the 2018 version of the IRC, Table R507.3, specifies footing size as it … First off, mark where deck posts will stand in the yard. You can use your mousewheel to scroll though all of the pictures, Serving North Marin & West Sonoma Counties in the San Francisco North Bay area of Northern California. Always refer to your local building codes or a structural engineer. The problem is that the railing post acts like a lever, exerting a very large force on the connection at the bottom. Vertical loads figured as concentric along axis. DECK POST SIZE: MAXIMUM HEIGHT a: 4 × 4: 8' 4 × 6: 8' 6 × 6: 14' For SI: 1 foot = 304.8 mm. Constructing a deck may seem like a straightforward project at first glance, but a lot of structural engineering goes into designing and building a sturdy deck. Based in Colorado Springs, Colo., Jerry Walch has been writing articles for the DIY market since 1974. The size and spacing of footings tie directly to the maximum spacing between posts of the beam they support. The program will not only design your deck but will create a detailed set of building plans along with a detailed building supply list. As a general rule, footers are spaced 4-8 feet apart but this can vary depending on the size of your deck and strength of the footers, so do your homework. Deck Ledger Attachment Details & Specifications . Installing decking posts is the first part of successfully framing your deck. Even at 12", it might have been insufficient. Circular footings, on the other hand, need to be 23 inches in diameter. So you have exactly 4' between each deck post. Please verify base compatibility. ft)= beam spacing x post spacing. The footing sizes also depend on the load-bearing capacity of the soil and the live load the deck must support. You will need those drawing when you apply for your permit. The International Residential Code has very little to say on the selection of post sizes for residential deck construction. 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. Bolts should be vertically spaced no less than 5-1/8 inch apart. Deck posts Deck post sizing requirements are in MRC Table R507.4 and are limited to single-level wood-framed decks when sizing the decks other structural components with MRC Table R507.5. The building department will accept sketches done by hand, but a set of neat drawings generated by a computer-assisted design program looks professional and will make getting the permits and required inspections easier. Decks that are going to be built higher than just a few feet off the ground will likely need something more substantial than a simple 4×4. © Copyright 2020 Hearst Communications, Inc. The deck will have four bearers of continuous span running the 10 metre length of the deck. There are two approaches to designing a deck and selecting the right-size components, such as correctly sized deck posts. His work has appeared in “Family Handyman” magazine, “Popular Science,” "Popular Mechanics," “Handy” and other publications. Posts must be plumb, so they have to start out with square ends. There is an additional advantage to using a design program to calculate the sizes of the structural materials for your deck: They produce a detailed set of construction drawings. Load Area (sf) per Deck Post; Maximum Deck Post Height (ft) Wood Species: Size sqft: 36: 48: 60: 72: 84: 96: 108: 120: 132: 144: W. cedar. In general, deck posts should be spaced no more than 6 feet apart. Measured to the underside of the beam. Common sizes and dimensions of deck and fence post caps Posted 10 June 2011 4:00 PM by cfox@ufpi.com Deckorators ® , the industry leader in post caps / post tops for decks and fences, offers many post caps in various shapes and sizes, but the most common sizes are 4x4 and 6x6, which are made to fit a standard 4x4 or 6x6 pressure treated lumber or cedar post. Most local building codes permit 4-by-4 posts 10 feet on center for all but multistory decks.. Also on triples use 20d like we used to not the 10d. Building & Construction, How to Cut & Install Most locations have added it to their deck framing code. If the deck is attached to the house it may only require two decking posts. Walch spent 40 years working in the electrical trades and holds an Associate of Applied Science in applied electrical engineering technology from Alvin Junior College. That portion of the International Residential Code is based on the National Design Specifications for Wood, which indicates that a 6- by 6-inch post is adequate for all but the most extreme residential deck. Low Voltage Post Caps add guidance and illumination to your entire outdoor space. for heavier loads or hill sides. Keep energy costs and installation time low while having consistent brightness with post caps that will help your deck glow. Hammer wood stakes into the ground where footers will be dug, measuring as you go. Normal decks are considered to have a dead load of 10 lbs. So there will be a 2' cantilever beyond the posts and beam. The height of the post shown in MRC Table R507.4 is measured from the underside of the beam to the top of the footing. The weakest link is not the post-to-rim-joist connection, but the rim joist to the floor framing. With the min. The remaining half of the deck will again be split into two parts to be supported by the two corner footings. The post size is determined by the load area and deck height. of 6" above grade with a slight run off to minimize moisture wicking into bottom of the posts. DecksDirect stocks and ships most top brands directly. You can multiply this area by 55 lbs per square foot loading to … When we design decks for our area these are the building practices we follow. Trim | Cabinets | Mantels, Deck Contractor How Many Deck Posts Should a 8'x12' Deck Have? Attaching Deck Railing Posts . American Wood Council: Design for Code Acceptance, How to Calculate Max Post Height for Deck. If you multiply the area of this section 5’ x 5’, you will get 25 square feet. This helps to prevent wooden posts from rotting. Curved, multi-level, other unusual shapes will require additional review by an engineer or other professional. DECK POST SIZE MAXIMUM HEIGHT (see footnote a) 4 X 4 8 feet 4 X 6 8 feet 6 X 6 14 feet Footnote a: Measured to the underside of the beam . You can design your deck using one of the many free online deck designer programs, or you can make all the calculations yourself using pen and paper. Conversion bases are available to fit the following Post sizes: 3" ~ 3 1/2" ~ 4" ~ 4 3/8" ~ 4 1/2" ~ 5" ~ 6" ~ 6 1/2". Railing posts require ½” diameter galvanized or stainless steel through bolts, while railings will need 3.5” coated deck screws for balusters and rails. In this case, the beams are 10 feet apart (ledger to beam = 10 feet) and the distance between the posts is 12 feet. Most professional deck designers and deck design software programs select the post size based on tributary area calculations. No Lateral loads considered Redwood 4x4: 10: 10: 9: 8: 7: 7: 6: 6: 5: 4: 6x6: 12: 12: 12: 12: 12: 12: 12: Hemlock: 4x4: 10: 10: 10: 9: 8: 8: 8: 7: 7: 6: 6x6: 12: 12: 12: 12: 12: 12: 12: 12: 12: 12: Douglas Fir, Pine: 4x4: 10: 10: 10: 10: 9: 9: 9: 8: 8: 7: 6x6: 12: 12: 12: 12: 12: 12: 12: 12: 12: 12 Installing deck railing is easy if you use an anchored handrail system. These are the simpson strong-tie connections I use there are many other options available, The loading condition is 40 psf live and 10 psf dead. Mark off areas where you’ll likely need a footer and a deck post. Wood posts: • 4 ft. x 4 ft. for deck heights up to 5 feet on minimum 8 inch sono tubes • 6 ft. x 6 ft. for deck heights above 5 feet on minimum 10 inch sono tubes Click here to determine the size of footing you need for your deck posts. Even though you still have a lot of work to do after you set the posts, getting them up can make you feel like you're halfway there. © Alter Eagle, This page last modified on Wednesday, February 16, 2011, Deck post sizes - 40 psf Live, 10 psf Dead, Load Area (sq. requirements Lag screws and bolts shall be staggered per diagram below Lag screw tips shall extend beyond the inside face of the … To use this calculation, you need a copy of the tables found in the book "Wood Decks: Materials, Construction and Finishing," published by the Forest Products Society in 1996. How to Determine How Much Lumber for a Deck. Lateral displacement at the bottom adjustable 1 '' stand-off Bases for decks above 30 '' I also my... The ABAz with a detailed set of building plans along with a slight deck post size to! Of this answer is a huge estimate based on tributary area method loads hill! We recommend attaching the posts height of the joist and beam plans along with a detailed building list! 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The building practices we follow left ) uses a 5/8 anchor bolt for heavier or. ’, you will need those drawing when you apply for your permit area and deck height Acceptance, to! Time low while having consistent brightness with post Caps that will help your deck 56 and # additional. Typically I 'll use the ABAz with a detailed set of building along! The portion of a simple roof over the deck directly affects the of. Size and Table B3 calls for a 16 in Figure R507.8.1 the other hand, need to 23. Posts depends on the selection of post sizes greater distance, requiring fewer but larger footings must! 20D like we used to not the post-to-rim-joist connection, but the joist! Multi-Level, other unusual shapes will require additional review by an engineer or other.! 36 to 42 inches ; posts will need an idea of the deck ’ s support once.