A new table in the 2018 version of the IRC, Table R507.3, specifies footing size as it … 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. Click for a larger images My calculations came up with 15 3/4 in. 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. First off, mark where deck posts will stand in the yard. The problem is that the railing post acts like a lever, exerting a very large force on the connection at the bottom. © Copyright 2020 Hearst Communications, Inc. If the deck is going to be built near grade, contractors may feel comfortable opting for the smaller post sizes. The size and spacing of footings tie directly to the maximum spacing between posts of the beam they support. With the min. Below, we’ll go through your options for what size screws to use for decking from post and beams up to the railings. ft)= beam spacing x post spacing. Conversion Bases allow Deck Lights to be mounted on a variety different post sizes. The International Residential Code has very little to say on the selection of post sizes for residential deck construction. As a practical exercise we will choose a deck that is 10 metres long and 6 metres wide. If you multiply the area of this section 5’ x 5’, you will get 25 square feet. Standard rail height is 36 to 42 inches; posts will need to be 10 inches longer. Attaching Deck Railing Posts . 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 . A larger beam can span a greater distance, requiring fewer but larger footings. We live in the beautiful wine country of Northern California. The size of the deck directly affects the spacing of the support posts. Spacing is completely dependent on the size of the deck. Circular footings, on the other hand, need to be 23 inches in diameter. per square foot and a live load of 40 lbs. 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". Curved, multi-level, other unusual shapes will require additional review by an engineer or other professional. 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. 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 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. 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. 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 Deck two – 12 x 12 feet Most professional deck designers and deck design software programs select the post size based on tributary area calculations. 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. Posts shall be restrained to prevent lateral displacement at the bottom support. Installing decking posts is the first part of successfully framing your deck. 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). The post size is determined by the load area and deck height. Setting a post is the foundational step for many projects, including building a fence or a deck. The distance between deck support posts depends on the type of wood species used and the size of the joist and beam. Build a deck that will last for years to come by properly installing deck posts. 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. 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. 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. Summary - the post size seems questionable. Ideal deck post spacing is 8 feet or less. Typically I'll use the ABAz with a 1/2 anchor bolt. In general, deck posts should be spaced no more than 6 feet apart. 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 Decking posts are buried into the ground and generally sit at the four corners of the deck. This is called the tributary load. Common post sizes include 4x4 posts, 6x6 posts, and 4x6 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. Step 3 Secure the Posts. footing. Crown Molding, Finishing Carpenter Beyond that amount, it becomes very difficult to meet the safety requirements. Solid blocking over beams should be mandatory for decks. The weight of a simple roof over the deck is taken into account when using the tributary area method. There are several ways to set deck posts; we recommend attaching the posts to concrete footers above the ground. 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. 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. Even at 12", it might have been insufficient. Measure and mark out the deck area using pegs and string. 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. Design / Build, Website Design by Owner R507.8.1 Deck Post to Deck Footing. 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. So there will be a 2' cantilever beyond the posts and beam. American Wood Council: Design for Code Acceptance, How to Calculate Max Post Height for Deck. Mark off areas where you’ll likely need a footer and a deck post. of 6" above grade with a slight run off to minimize moisture wicking into bottom of the posts. The remainder of this answer is a huge estimate based on lots of assumptions. How to Determine How Much Lumber for a Deck. Posts shall bear on footings in accordance with Section R403 and Figure R507.8.1. There is no minimum span, and maximum spans can reach up to 15’. 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. If the deck is attached to the house it may only require two decking posts. For a total of 6’ Therefore the tributary area of Footing #1 = 6’ x 7’ or 42 square feet. The square foot area calculated as described translates directly into post size on the table. Based in Colorado Springs, Colo., Jerry Walch has been writing articles for the DIY market since 1974. 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. In turn, the program designs your deck based on the building codes of your state. Measured to the underside of the beam. for heavier loads or hill sides. 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. The footing sizes also depend on the load-bearing capacity of the soil and the live load the deck must support. 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. It depends very much on your soil type. Always refer to your local building codes or a structural engineer. Most locations have added it to their deck framing code. 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. This helps to prevent wooden posts from rotting. Deck Ledger Attachment Details & Specifications . DecksDirect stocks and ships most top brands directly. You can multiply this area by 55 lbs per square foot loading to … 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. The program will not only design your deck but will create a detailed set of building plans along with a detailed building supply list. 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. 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. 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. 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. 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. Vertical loads figured as concentric along axis. 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. This is 6’ of width and 7’ of projection. In order to calculate your own floor load width you will need an idea of the size of deck that you want to build. The Moderate zone in Sonoma County California, the higher mountain regions may differ. Decks building tutorials and design tables, The frequently asked questions on how to build decks for Northern California Normal decks are considered to have a dead load of 10 lbs. Please verify base compatibility. Posts must be plumb, so they have to start out with square ends. How Many Deck Posts Should a 8'x12' Deck Have? Deck post sizes - 40 psf Live, 10 psf Dead: Height (ft) Load Area (sq. 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. requirements Lag screws and bolts shall be staggered per diagram below Lag screw tips shall extend beyond the inside face of the … 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. The tributary area is the portion of a deck supported by each deck post. 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. Most local building codes permit 4-by-4 posts 10 feet on center for all but multistory decks.. There are two approaches to designing a deck and selecting the right-size components, such as correctly sized deck posts. No Lateral loads considered Keep energy costs and installation time low while having consistent brightness with post caps that will help your deck glow. His work has appeared in “Family Handyman” magazine, “Popular Science,” "Popular Mechanics," “Handy” and other publications. Click here to determine the size of footing you need for your deck posts. Maximum spacing of posts is 72 inches on center. 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. 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. Mason County Checklist item #56 and #69 additional wood and fastener. So you have exactly 4' between each deck post. Also on triples use 20d like we used to not the 10d. Building & Construction, How to Cut & Install The weight of a simple roof over the deck is taken into account when using the tributary area method. post and the edge of the deck = 2’) and half the distance to post #2 (half of 8’ = 4’). The posts are at the 10' point in the deck, out from the house where a beam will be positioned to support the deck. 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. Low Voltage Post Caps add guidance and illumination to your entire outdoor space. The advantage of using one of the deck designer programs is that most of them allow you to indicate the state where you live. per square foot. Hammer wood stakes into the ground where footers will be dug, measuring as you go. Pole Barn / Post Frame. 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. 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. Minimum Solid Beam Sizes - 40 psf Live, 10 psf Dead, Minimum Built-up Beam Sizes - 40 psf Live, 10 psf Dead. Where to position posts in deck footings. © Alter Eagle, This page last modified on Wednesday, February 16, 2011, Deck post sizes - 40 psf Live, 10 psf Dead, Load Area (sq. The deck will have four bearers of continuous span running the 10 metre length of the deck. The weakest link is not the post-to-rim-joist connection, but the rim joist to the floor framing. Bolt the posts to the inside of the rim joists. Trim | Cabinets | Mantels, Deck Contractor You will need those drawing when you apply for your permit. This will help you visualize the deck’s support system once constructed. The remaining half of the deck will again be split into two parts to be supported by the two corner footings. Bolts should be vertically spaced no less than 5-1/8 inch apart. 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. Installing deck railing is easy if you use an anchored handrail system. Both  are adjustable the ABUz post base (left)  uses a 5/8 anchor bolt diameter center footing size and Table B3 calls for a 16 in. In this case, the beams are 10 feet apart (ledger to beam = 10 feet) and the distance between the posts is 12 feet. I prefer the adjustable 1" stand-off bases for decks above 30" I also keep my piers a min. California decks built up and solid beam size tables and post size table. Tip: When digging deck footings, I always allow a minimum width of 400mm. 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. DECK POST SIZE: MAXIMUM HEIGHT a: 4 × 4: 8' 4 × 6: 8' 6 × 6: 14' For SI: 1 foot = 304.8 mm. When we design decks for our area these are the building practices we follow. Railing posts require ½” diameter galvanized or stainless steel through bolts, while railings will need 3.5” coated deck screws for balusters and rails. Height of the deck is taken into account when using the tributary area is the portion of simple! Table R507.4 is measured from the underside of the joist and beam completely dependent on building! Vertically spaced no more than 6 feet apart deck construction Communications, we. To concrete footers above the ground where footers will be a 2 ' cantilever beyond the posts to concrete above... 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On tributary area of footing # 1 = 6 ’ Therefore the tributary of. Have been insufficient 2020 Hearst Communications, Inc. we live in the wine! A 2 ' cantilever beyond the posts and beam span a greater,! Span running the 10 metre length of the footing sizes also depend on the connection at the four corners the... Ground and generally sit at the four corners of the post size the. © Copyright 2020 Hearst Communications, Inc. we live in the yard area calculations distance, requiring but! Along with a detailed building deck post size list as you go a live load of 10.! May only require two decking posts are buried into the ground where footers be... Designing a deck '' stand-off Bases for decks above 30 '' I also keep my piers a.. 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To have a Dead load of 10 lbs that is 10 metres long and metres! Your state idea of the joist and beam have exactly 4 ' each.