The greater the joist spans and the narrower the beam, the shorter the distance between beam support posts. Without the below listed cutting instruments you might not get proper cut while you might be injured without safety tools. The 4×4 should not be notched to the deck. Always refer to your local building codes or a structural engineer. Deck posts support the weight of the deck material and everything that rests on it. The future is … Maximum cantilever of a 2X8 is 24” at 16” o.c. The local building code should identify which is acceptable in your area but may site both with given parameters. One of the easiest methods is to cut a 24-inch rabbet into the connecting ends. You'll need the post layout marked before you begin. 5. So now we have a two story deck (underneath is a carport area) that is supported by six 6x6" posts, stacked on top of six 6x6" posts. Distance Between Deck Posts . When connecting two 4x4s together for vertical use, there are different ways to cut and fasten the ends together to ensure even distribution of stress forces. In this article, we’ll explain 4×4 and 6×6 posts, when and where to use them, how to secure them to a beam, and the spacing between post supports. An intermediate landing must be built if the stairs exceed a vertical height of 12’-0” but may be used to shorten smaller stringer spans. Most locations have added it to their deck framing code. Live-load or snow-load are other factors to consider, as are deck size and use. A 6×6 post is able to carry 2 without the use of special brackets or caps, but all 3-ply beams must have them. Short posts support more weight and deck area, while taller posts support less and require additional lateral bracing. The post should also be secured to the footing. The IRC sets the guidelines most locales follow. Also on triples use 20d like we used to not the 10d. Space Near Pool: If you have a pool, a deck can improve safety around the water and adds more walking space around your pool. The distance between posts, beam dimensions, plus the joist span, spacing, and dimensions also factor into load calculations. Attempting a build on a 20' by 24' rectangle Flat deck, on a basically flat backyard, not attached to my home. Maximum Joist Spacing for Decks Southern Pine Deck Joist Maximum Spans No Cantilever With Cantilever* *Joists may cantilever up to ¼ of the actual adjacent span. It also must be flush with the postface for full bearing. Joist spacing is limited by the decking boards per the table in the code or manufacturer’s instructions. Crafting an outdoor space for your loved ones to relax and enjoy time together on is a beautiful, lasting gift to both your family and yourself. Thicker beams will support more and allow for wider post spacing. Design / Build, Website Design by Owner
Remodeled Deck Railing Doesn’t Reach Stair Landing. See the Deck Post Size Table to make that determination because it … stair, pier spacing, joist span and maximum height of the deck above grade. California decks built up and solid beam size tables and post size table. Maximum Allowable Height for a 4×4 Deck Support Post. Short posts support more weight and deck area, while taller posts support less and require additional lateral bracing. The 4×4 post must be notched to fit the stringer and bolted with (2) 1/2″ through-bolts with washers. We’ll also look at posts for deck stairs and deck railings. Click for a larger images
We feature articles on how to install continuous concrete pier foundations, belled piers, footing forms and the buried post on top of the footing method. ft)= beam spacing x post spacing. When splicing a beam, the splice must meet in the middle of the notch. 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. Through bolts must have a washer under the head and nut. The manufactured connectors make it easy to fasten single to triple-ply beams to post tops. A 4×4 is less expensive than a 6×6 of equal length. 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. Most professionals will encourage you to consider going with a 6×6 deck post form the outset of the project. Gardening: Those of you with a green thumb, you can create a container garden with a new deck. A deck support post must withstand concentric compression and eccentric loads. But, if you need to add post caps to the 4×4 to do what a notched 6×6 will do, the savings may be negligible. To avoid code violations, many deck builders choose the 6×6 even if the 4×4 is acceptable. One way is to pour concrete in the post hole, set the post on the concrete and backfill with gravel. As a general rule, the best “bang for your buck” is most typically spaced every 12 feet, although 10 foot and 14 foot spacings are often a close second. There must be 2-1/2” or more between bolts vertically and at least 3/4″ between the bolt and the edge of the post. In the event of a single truss failure, this system will result in a domino effect and the collapse of the entire roof system. The maximum limit dropped to 6’-9” for a 3-ply beam secured to the top of the post by a cap or bracket. It’s important to note, the greater the load area, the more weight on individual posts. Eccentric loads are forces that act in other ways on the post – lateral, diagonal, or torque forces – which can cause a post to fail. During your planning stage, don’t forget to consider the spacing for your beams. While a typical deck under 6 feet in height may only require posts set every 5 to 8 feet, the type of deck, the type of wood, the height of the deck and a variety of other factors can influence the spacing of the support posts. The best Grade of lumber (Southern Pine) for the maximum spans identified support Tributary Areas of 159sq.ft, which is why the maximum Tributary Area is 160sq.ft. Minimum Solid Beam Sizes - 40 psf Live, 10 psf Dead, Minimum Built-up Beam Sizes - 40 psf Live, 10 psf Dead. Most codes require posts to be fastened or secured at the bottom (footing) and the top (beam) to prevent lateral movement and uplift forces. The distance horizontally between bolts must be less than 5-inches. The maximum allowable 4×4 deck support post height under the 2015 IRC is 8-feet. Deck Calculator Tips. Crown Molding, Finishing Carpenter
Vertical loads figured as concentric along axis. A 1 or 2-ply beam, or equivalent, can still mount atop an 8-foot 4×4 post. Aesthetically, a larger post may look better than a narrower post, or vice-versa, especially if the deck is small. High grades or stronger wood species support greater areas for similar lengths. 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
Shorter posts will support heavier weights as they are less likely to bend and snap like a toothpick squeezed at both ends. DEAR RICK: The most efficient post spacing is going to depend upon the wind and snow load conditions at any particular given pole building site. However, for most decks, 50psf is a safe load value. I'm burying 4x4 posts in Concrete as I did with my large fence. However, the industry and code acknowledge the difference and rate the post accordingly – 4×4 sounds better too. However, an 8-foot 4×4 supports 6468-pounds and 2339-pounds at 14-feet, while a 6×6 is 18032 and 10550-pounds respectively – or 64% and 78% more load capacity. To minimize twisting, diagonally brace the top of the post and bottom of the beam, or fasten a block to connect the side the beam with the side of the post. However, it is advisable to always check with the local building department as some only permit 6×6 and some permit both for specified heights. As always, your comments and suggestions are appreciated. 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. Deck support posts are normally placed near the ends of beams and spaced along the length of the beam. Any post more than 8 feet long we use 4x6 or 6x6. The “6×6 Deck Support Posts” table identifies tributary areas for #2-SPF lumber. The maximum spacing of 4x4 deck posts should be 6 feet on center, while the maximum spacing of 6x6 deck posts should be … For my money, I’ll use a 6×6. The footings are constructed using a round cardboard tube form that is 8” in diameter (often called a sonotube, after a popular brand). Post Anchors are made to support a maximum raililng height of 42 inches. They are commonly secured at or above ground level with a metal bracket to a footing, pier, or deck block, and to the beam at the other end to prevent twisting. Shorter posts will support more weight than taller posts, but the Tributary Area limits allowable heights. We live in the beautiful wine country of Northern California. In most of the civilized world you will need a design to code and a permit, especially if you ever try to sell the house. There are other forces that frequently come into play when designing a deck – snow load, wind load, earthquake stresses. Building a deck is a great way to extend the outdoor living space of a home or business. The type of wood and length of post influence how much it will support before snapping. All posts must meet some eccentric stresses since most wooden posts aren’t perfectly straight. The best Grade of lumber (Southern Pine) for the maximum spans identified support Tributary Areas of 159sq.ft. The Moderate zone in Sonoma County California, the higher mountain regions may differ. The Deck Support Post Spacing table provides the post spacing based on joist span and beam dimensions. The spacing depends upon the beam thickness and width, and the distances the joists span. The thicker wood dimensions are less susceptible to bending as the length of the post increases. Keep in mind that these figures depend on the size and spacing of … With the min. To ensure decks are safe for what you plan, check with the local building department and a Structural Engineer, especially if the deck will carry heavy items. Rails connect to postcovers using 2x4 rail connectors, or the provided connectors. The tributary areas of the center posts are the same, the major difference is the area the corner posts support due to less lateral strength. So, for posts 3-feet and shorter, it’s a matter of preference, above 3-feet use 6×6. If your deck is slightly out of square (different widths), calculate results for both widths, and set out each end to suit. A 4-by-10 can usually span up to 12 feet between posts. Planning to install a hot tub or a spa also influence post size decisions, and should involve the input of a Structural Engineer at the design stage. 3. Decks, Patios, Porches, Walkways, Driveways, Stairs, Steps and Docks - 6x6 post spacing - Over a 20 ft 8 span, would it be ok to just use 3- 6x6 posts. Your post footings are the foundation of your deck and just like your house, the deck is only as strong as its foundation. Unless prohibited in your area, a 4×4 post is acceptable for deck supports up to 8-feet in height for a 1 or 2-ply beam within the identified parameters. How much they support is based on the tributary area and post height. When we design decks for our area these are the building practices we follow. The International Residential Building Code (IRC) and the International Building Code (IBC) act as guidelines for national and state building codes in whole or in part. for Live Loads of 40, 50, 60 and 70psf. Making sure it is solid and structurally sound from the ground up though, is often a matter of 4×4 vs 6×6 deck post. There must be 3/4″ or more of the stringer below the bottom bolt, and at least 2-inches of the stringer above the top bolt. He is passionately interested in home improvement, renovation and woodworking. The 6×6 is larger and checks and cracks will be more visible, however, it may not twist or bend like a 4×4. The nominal 6×6 is actually 5-1/2” x 5-1/2” and offers ample support to 3-ply dimensional lumber beams, which is why many deck builders and DIYers use them for all deck support purposes. The type of wood, the post length, and how wet or dry the location impact the load rating of posts and should also be taken into account. I hope you have a better understanding of the similarities and differences between 4×4 and 6×6 deck support posts, stair posts, and railing posts, and how to fasten posts and beams together. The load the deck carries is expressed in pounds per square foot (PSF or psf) in much of North America. Both are adjustable the ABUz post base (left) uses a 5/8 anchor bolt
See Engineering Reports for horizontal, compression and tension loads. for heavier loads or hill sides. The Building Code for most jurisdictions identifies what materials and dimensions of deck support posts are acceptable. Instead of notching the beam, post-to-beam caps or connectors may be used to prevent lateral and vertical movement. Our deck plans are designed to be used with poured footings and posts set in brackets attached to the top of the footing. Building & Construction, How to Cut & Install
Many deck builders and DIYers tend to use 6×6 support posts and so bypass any arguments or concerns. The manufactured connectors must be the appropriate size for the post and beam. So, which is better? TOOLS NEEDED TO CUT 6X6 POST: Before going to cut your 6×6 deck post or fence post, you must gather some cutting and safety tools for having appropriate cut safely. Here is a great tip on how to securely attach beams to 6x6 support posts for a free standing deck. The bigger post will support larger tributary areas at greater heights and is stronger laterally. Changing the post spacing is a major structural change and will require a new design for the current code and a permit. The deck post spacing will ensure you can enjoy the outdoor area for decades. To determine exactly how much decking material you need for your new deck, please fill in your desired specs into our calculator above. If a deck is raised more than 6 feet above the ground, codes may require 6x6 posts. The Tributary Area multiplied by the ‘dead’ (10psf) and ‘live’ (40psf) load rating, or the design load (50psf), identifies the weight the post may support. In general, the maximum span for a 4-by-6 beam is 6 feet between 4-by-4 posts. Maximum cantilever of a double 2X8 beam past a support post is 12” On my own deck, I had to replace a 6x6 after a year, when it bowed almost 1 1/2 inches. Postcovers easily integrate into most deck or porch designs, working equally well with wood, composite or vinyl railings. If you found this article a good guide to assist in the selection and securing of deck support posts, please share it with others. Note: The 2018 IRC Table R507.3 identifies Tributary Areas of 20 to 160sq.ft. 5 Tips on How to Build a Strong Deck Frame. All cuts and boreholes should be field dressed with wood preservative to prevent rot and moisture. 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