Privacy Screens -How High Can I Go With Titan Wood Post Anchor? Determine the length of the joist actually supported by the beam. Having the right number of deck beams is essential to building a safe and sturdy deck. the maximum span of a given beam between posts. required to support that beam. Bigger beams also mean a greater span. When calculating beam span, the general rule of thumb is pretty straightforward: the longer a beam spans, the bigger it needs to be to support that span. When building a deck with 7-ft. joists, you know the beam can span somewhere between 7-7 and 8-0, but you don’t know exactly where. Remember to complete all calculations using millimetres. I am looking to install privacy screens on my concrete patio. A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on. The standard rule for footings is that for a basic deck, the larger the beam and footing size, the fewer footings you'll need. So, for example, a 16-foot beam span can cantilever a maximum of 4 feet. Joist Spacing for Composite Decking Total height of low level ground level deck. In this article, we’ll review how to calculate deck beam spacing based on different lumber sizes and how to determine the number of deck beams you’ll need for your project. It also depends on the joist spacing. The narrower the spacing between joists, the greater the span can be. Drill through the beam with a long bit the same diameter as the bolts. The International Residential Building Code requires that you have enough deck beams to support the deck’s joists adequately. Cantilevering the beams allows the posts to be partially concealed beneath the deck, creating a more visually appealing look. spacing. Lumber Species Southern Pine Douglas Fir Douglas Fir-Larch Hemlock-Fir Spruce-Pine-Fir Redwood Western Cedar Ponderosa Pine Red Pine The International Residential Building Code (IRC) has strict requirements for deck beams and deck beam spacing. It’s essential to comply with the building code to ensure proper deck post, footing, and beam spacing. A two-ply 2×10 beam, for example, has an allowable span of just 6 feet 9 inches for a joist spanning 14 feet and 6 feet 4 inches on 16 feet. If you have internal beams, stagger the splices on each so they aren’t lined up on the deck. the joist plus any cantilevered portion of the joist past the beam. To provide support for the joists, deck beams must span the entire length of the deck. Even though a deck that extends 15 feet from the house with 2×8 joists may only be a few feet longer than the minimum span, you’ll need an additional beam to provide adequate support and adhere to building code. Obviously, the larger Span entries are listed for 2×6 through 2×12 joists and 12 in., 16 in., and 24 in. Most dimensional lumber maxes out at 20 feet. The span of the joists the beam is supporting also determines the maximum deck beam span between support posts. The drop beam design has two advantages. When supporting joists that span 12 feet with no overhang beyond the beam, a double ply beam can span in feet a value equal to its depth in inches. However, the type and grade of wood needs to be considered. The joists will then extend over the beam in a cantilever position. Example: a = 12'; Post spacing # 8' Use the joist span table to find the acceptable joist sizes for a 12' span, 2x8s at 12" O.C., 2x10s at 16" O.C., or 2x12s at 24" O.C. Lumber Species Southern Pine Douglas Fir Douglas Fir-Larch Hemlock-Fir Spruce-Pine-Fir Redwood Western Cedar Ponderosa Pine Red Pine Home > Building A … determines the force that bears upon that beam and therefore the This, of course, would mean the additional cost of a second beam, support posts and footings along with the labor of digging the footings and installing the posts. This translates into fewer holes to dig and materials to purchase. Deck joist spacing is the distance between joists, measured from the center of one joist to the center of the next, and is commonly 12, 16, or 24-inches. Flush beams are typically used for small decks or those with unconventional shapes where drop or cantilever beams won’t work. the beam, the greater the distance it can span between posts. Maximum 2x6 Deck Joist Span A Redwood Keep in mind that some species are only available in certain parts of the country. Beam Spacing. Decking Beam Span Guidance We recommend beams are constructed from two 44 x 145mm Q-Deck deck joists and are placed at maximum centres of 1.8m. Joist direction, size and spacing Location of posts and deck blocks supporting beam Spans between beam support posts Beam cantilever distance (if applicable) Dimensions of the deck Area of the deck Stair location (if applicable) The location of the house relative to the new deck Stair dimensions See the deck joist calculations below and study your local code. Remember, you need enough beams to keep the span of the joists in code. First, plan where the splice will be located on the beam. But how many beams do you need, and how should they be spaced? I hope this article answered all of your questions. The formula looks like this: (Overall length of deck – Floor joist thickness) “Maximum floor joist spacing/centre” Now your final answer is almost never a round number. The greater the joist span, the less distance the beam can span. Cost estimates and framing layouts are provided for comparison only; actual costs will vary for different markets. Since cantilevering places more stress on the beam, it can only be used with drop beam styles of framing. In this case, you’ll need to splice your deck beams to extend length of the beam. The ends of each joist, beam or girder shall have at least 1 ½" of bearing on wood or metal except where supported on a 1"x4" ribbon strip nailed to adjacent studs. This table compares requirements at both minimum (50 psf) and elevated (70 psf) design loads. With this in mind, the depth of the joist determines the spacing of the beams. While this can vary depending on the size, species, and grade of the framing lumber, a deck with 2×8 southern pine joists spaced 16 inches apart must be supported by a beam a maximum of every 12 feet. Secure the beams to the post using four carriage bolts. The more weight, or You can use two beams, one at 7.5 feet and one at 15 feet, to provide support. The span of the joists the beam is supporting also determines the maximum deck beam span between support posts. A Redwood 4x6 beam should span no more than 6' between supporting posts. Joist Spacing & Span. A 20-foot wide deck, for example, would require two beams: one at 10 feet and one and 20 feet in order to support a deck with 2×8 joists spaced 16 inches apart. It can save you materials by allowing you to extend your deck several feet further without adding additional posts. He is passionately interested in home improvement, renovation and woodworking. Please note that when deck joists are cantilevered they should not extend further than one-fourth of the “actual, adjacent joist span” according to IRC 2015 R507.5. Some builders position them every 4 feet for a completely rigid frame. The Beam Table indicates that the beam may be two 2x10s or two 2x12s, depending on the wood used. Beams rest on and secure to Code compliant and spaced deck posts and footings for support. All Rights Reserved. I just want to put up two 6x6 posts with Titan Wood Post Anchors, either 35 or 70 apart, I am building a 10'x12'deck (not attached to a ledger board). This means for a 12-foot span, you can cantilever up to three feet beyond the beam. Composite decking brands also generally require 12 inches O.C.joist spacing for 45-degree or angled composite deck board applications. © 2004-2019 Decksgo.com. While cantilevering can add width to your deck and eliminate the need for additional footings, posts and beams, sometimes it isn’t enough. The last board won’t look good if it’s skinny or cut at an angle. It makes sense if you think about it. 4x6 beam should span no more than 6' between supporting posts. The length of joist span actually supported by a beam is what You would only need one deck beam for a small deck that is 12 feet wide or less in the above example. A 3 ply 2×10 beam can handle a span of 8 feet 6 inches for a joist spanning 14 feet and 7 feet 11 inches at 16 feet. The weight load of your deck also affects the spacing of the posts. Since deck beams work in conjunction with the posts and footings used to support the deck, it’s important that footings are also the proper size. When the deck joists are 8 ft. long, the beam can span 7-7. Once you understand the limitations of the joist span on your deck, you can determine how many beams you need. For Beam 1, use a joist length of 13’, (6’+7’) and a post spacing of 9’. Below are some common beam span values from Table R507.5 of the 2018 IRC: A cantilevered beam extends beyond the end post or posts. During Drop beams are also stronger than flush beams because they rely on the wood structure to support the weight rather than metal fasteners. Fasten the deck boards at each joist. Why use a cantilever? The Joist Span indicates that 2x6s at 24” O.C. (on center) for standard straight composite decking installation. Determining proper deck beam spacing can be confusing. There are two types of deck beams to consider: flush beams and drop beams. distance that a given size of beam can span before another post is Working in concert with the deck posts and footings, a deck beam is responsible for holding up the joists, which holds up the decking. Refer to the Deck Beam Span Table below to assist in determining According to IRC, a two-ply 2×10 beam supporting a joist that spans 8 feet between supports requires beam support posts every 9-feet. The thickness of the beam determines how far a beam can span between support posts. The distance you choose affects the maximum span, or how long your joists can be without compromising the strength of the deck frame. Starting with your perimeter, mark the location of each deck post to locate the fitting position. In the example below, the post spacing is changed from 96" to 48". The footing dimensions are determined by assessing the joist length and the post spacing for the tributary area. Whereas a 10 feet can span up to 6 feet 6 inches. In this instance the maximum span between deck post centres is 2.07m (C16) or 2.24m (C24). A deck with 2×8 joists spaced 16 inches apart will need to be supported at least every 12 feet to provide adequate support for the joists and comply with building codes. What if your deck is more than 20 feet long? That is a fairly simplistic way of looking at it. But let’s first explain what the numbers in the chart actually mean, because it can be a bit confusing. This may mean you only need one beam plus the ledger board attached to the house for smaller decks. If the outside edge of your deck is at least 17” above grade, a double 2x8 beam should be installed to support the joists along the outside. Making sure that your deck has the right number of beams that are properly spaced is critical to ensure it adheres to building code requirements and is safe for your family and guests. The beams are (3x)2x6x16 glued and screwed together. Deck beam span table Deck joist span table Deck joist rule of thumb Deck & Porch Construction & Structural Fasteners Deck & Porch Post & Beam Connectors: steel post cap connectors, plywood post to beam cleats, other connectors Deck & Porch Railings, Code Requirements, Safety Deck framing tables, codes, specifications Questions & answers about allowable spans for deck, floor, or porch framing. Plan in advance by knowing the correct deck beam span to use. The Deck Beam Span Table on this page makes it easy to determine how far apart your posts and therefore the span of the beam should be. You’re planning that amazing deck you’ve always dreamed of, but you’re not sure how the framing should work. The maximum distance between footings is … 5/4 x 6 pressure-treated decking may be placed with each board flush against the next; natural shrinkage will provide the proper spacing. The IRC also regulates how far a deck beam can span before it needs support from a post and footing. A double-ply beam can span in feet the number of inches it is deep For example, a double 2×12 beam can span up to 12 feet while a double 2×10 can span up to 10 feet. you already understand the relationship between joist span and joist Then divide this measurement by the maximum floor joist spacing that is mentioned on your drawings. A drop beam is positioned under the joists to bear the weight of the frame. You must use 2x material bolted together to create a deck beam, or use metal or engineered lumber. Whereas a 10 feet can span up to 6 feet 6 inches. Cut a 3-inch-wide notch in the post to match the width of the beam. Use the Beam and footing sizes table and find the 8' post spacing column. the longer the supported length of joist that a beam must carry, the Figure 2. Joists may bear on the beam and extend past the beam face up to the lesser of L O beams or a beam and a ledger, each beam (or ledger) supports half of the Joist Size and Spacing would be adequate for this span. See the Deck Post Size Table to make that determination because it will affect the size of beam you choose. In most cases, it’s best to start with a full board on the outside edge of the deck and work toward the house so the odd board is … To determine the correct joist required, we need to establish the spacing of our joists. The tributary area, coupled with the live load or snow load for the locale, and the soil’s load bearing value are used to identify the required dimensions of the footing (Reference Table R507.3.1 of the 2018 IRC).. Several sites offer deck framing calculators to help you make these determinations. A steel beam can hold remarkably more than a wood beam, which reduces the number of support posts needed. 2" thick deck boards should be spaced approximately 1/8"; most builders set a 16d nail between the boards as they fasten them. For determining beam spans (distance a beam can span between It allows the beams to extend beyond the post for a short distance which is called cantilevering. Obviously, the larger the beam, the greater the distance it can span between posts. Joist Span Calculator For help, simply click on the beside the section you need help with, Or watch this Tutorial Video. A flush beam is positioned at the same level as the joists. If you're building a simple deck, footings and posts should be placed less than 8 feet apart. There’s also an aesthetic benefit to a cantilever. According to IRC, a two-ply 2×10 beam supporting a joist that spans 8 feet between supports requires beam support posts every 9-feet. Install the two beams so the ends butt together and rest on the notch. use. If the width of the deck exceeds this span, you’ll need more beams. So, rather than using a 6×6 beam, this would mean using three 2x6s bolted together. For the calculations in this article, we will use treated southern pine, which is the most common wood for beams and offers the greatest span of any wood type. The required width of a joist depends on its span: how far it must travel between beams or between a beam and a ledger. In the past, 4x4s and 6×6 lumber could serve as beams, that is no longer the case. Joist Span – Non-Ledger Deck. Red pine, fir, hemlock, cedar, redwood, and SPF (spruce-pine-fir) are just a few species that also function as beams. Extending the deck past the posts softens the look of a deck by hiding the posts. Span is also dependent on the material. In the example below, the offset is changed from 12" to 24". the midway point between the supported ends (either a ledger or beam) of A deck beam is a board or collection of boards that support the deck joists and decking. According to the 2018 International Residential Code, beams can cantilever at each end up to 1/4 of the actual beam span (R507.5). Deck Post Spacing. Repeat this process at 16-inch intervals across the length of the beam. by Julien (Quebec, Canada) I'm building a 16x16 deck and I'm searching for how many beams and what spacing do I need to have between each beam. A 2×6 joist can span up to 9 feet, a 2×8 can span up to 12 feet, and a 2×10 can span up to 15 feet. For example, to cover a 30-foot space, you might use two 2x8x10s and two 2x8x20s. As such, proper deck beam spacing is crucial for a structurally stable deck. To calculate beam span, you need to consider the wood species and grade, size of the beam, and the joist span. The Joist span table below is for joists with a continuous span on a deck below 1metre in height. Most decks use 16" on center spacing for joists. Step 2: Run String Lines to Ensure All Joists Are Level & In Plane. The end of each beam shall have a minimum of 1 ½â€ of bearing on wood or metal or 3“on masonry located at interior posts Joist Beam Ledger Board 2 rows 10d (3” X.128”) nails or wood screws placed 16” O along edge of both sides of beam (2) ½â€ diameter through-bolts with washers under head and nut 5 ½â€ min. For Beam 2, use a joist length of 7’ and post spacing … Remember, the IRC allows you to cantilever joists up to one-fourth of the joist’s span from beam to beam (or in this case, from ledger board to beam). If you have seen the Deck Joist Span Table, How Do I make a Beam Longer Than the Length of the Lumber. For a deck that is 15 feet wide with 2×10 joists spaced at 16 inches apart, you have two options. Refer to the Deck Beam Span Table below to assist in determining the maximum span of a given beam between posts. Changing joist span, depth, and spacing has a dramatic effect on deck strength. Beam Deck Post Post Cap 2 ½â€ min. Most decking is not strong enough to support longer spans than 16". Some builders reduce joist spacing to 12" on center to strengthen the deck frame or to increase maximum allowable joist spans. Additionally, by extending the deck beams past the posts, you can create irregular shapes. Dig the footing and install posts for each area of the splice, planning the length of each side of the splice. Beams are made out of a variety of treated dimensional lumber. BEAM SIZE & ASSEMBLY REQUIREMENTS Deck beam spans shall be in accordance with Table 3 and can extend past the post face up to L B /4 as shown in Figure 3. Joist Span – Joists Attached at House and to Side of Beam. Although we used International Residential Building Code requirements to make our calculations in this article, it’s important to check your local building codes to see if your municipality’s requirements are more stringent. With composites, you can typically trust brand guidelines but should make adjustments depending on the angle and span of your deck. Beam Span Calculator For help, simply click on the beside the section you need help with, watch this Tutorial Video. Joists spaced the standard 16 inches apart can span 1.5 times their depth in feet. Most span tables use Southern pine for their calculations, but this isn’t the only material you can use for a beam. This will ensure a stronger frame. Dimensional Lumber She would like it to be as high as possible, with. In that case, the required spacing of the posts will be based on the deck loading, the span of the beams, and the geometry of the deck. The smaller the spacing, the longer your joists can span. Refer to Table R507.5 of the 2018 IRC for specifics. In general, posts should be spaced no more than 8 feet apart. up to a point. To properly space deck beams, you need to consider the joist span. Use this to specify the distance the deck posts are offset from the end of the beam. They may be a single plank, or consist of two, three, or even four 2x8s, 2x10s, or 2×12 boards fastened together with bolts or nails. Deck beams typically run perpendicularly to the joists and may run parallel or perpendicular to a structure. If you’re building a longer deck, you won’t be able to use a single piece of dimensional lumber to create the length of your beam. your planning stage, don’t forget to consider the spacing for your Figure 1B. joist. If you are still unsure what the deck beam requirements are for your deck design, feel free to reach out using the comment box below. This distance is half the distance to the next beam in either direction. Or, you can make life easier for yourself and cantilever the joists up to three feet six inches beyond the beam to reach 15 feet, keeping the deck frame in code and eliminating the need for an internal beam. First, the IRC only allows certain dimensional lumber to be used for deck beams. The closer you space joists, the longer you can span joists – For instance, joists that are placed 24 inches apart must be wider than joists placed 16 inches apart. Larger decks commonly require additional deck beams in the middle to provide support. If a joist is attached from a ledger to a beam, then the distance is If a joist spans between two How to build deck stairs Stair height calculation table Decks building tutorials and design tables With a 12' deck span, the beam may be either two 2x8s or two 2x10s, depending on the wood used. Use this to specify the spacing between the posts that support the deck. The maximum joist spans below are based on a ground snow and live load of 40 pounds per square foot and a dead load of 10 pounds per square foot. supporting posts), consider the following concept. Adjust the spacing between deck boards gradually over the next 10 rows of decking until the distance to the house is equal. Starting about 2 inches from the edges of the beam, counterbore two holes on the inside (or the least-visible side) of the beam for carriage bolt nuts. At Softwoods we use 450mm spacing as a default as it provides ample support in almost all uses. Deck Joist Spacing & Blocking Tips Step 1: Check That Your Deck Frame Is Structurally Sound. Offset From End. Smaller decks typically rely on a single beam that runs along the deck’s outer edge, providing support for the joists in conjunction with the ledger board attached to the house. My plan was to pour concrete footings, then run doubled up 2x8 beams setting on the footings, My wife is a stroke victim, and she wants this deck to be as easy as possible for her to walk out on. beams. Eugene has been a DIY enthusiast for most of his life and loves being creative while inspiring creativity in others. shorter the span of the beam – for a particular size of beam. The limitations of how far a joist can span determines just how many beams you’ll need. Deck beams serve an integral role in the framing of your deck. Check with your local code official, or simply drop back to the shorter value in the table and assume the allowable span is 7-7. on-center spacing. Lightweight steel beams are becoming more popular due to their durability and precision. This is where cantilevering can save you time and money. However, if your deck will include a hot tub or roof, you must support that weight with additional footings. The span is the distance a joist traverses from ledger to beam, or beam to beam, without support. The majority of composite deck board brands including Trex, TimberTech, and more require deck joists spacing to be at 16 inches O.C. Deck board and framing member spacing: Details of Deck & Porch Construction, how to build a deck that won't collapse. You should also know the size of the post you are considering to With a flush beam, the joists are attached to the beam using joist hangers.