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. The calculations below list approximate recommended deck beam spans. There are other beam provisions and limitations in the 2015 IRC to take note of: Even if your local code jurisdiction hasn’t adopted the 2015 IRC, most building officials will look favorably on an ICC sanctioned code provision. Specific design guidance includes convenient span tables for joists and beams and charts of post sizing limitations and connection methods. With a 12’ deck span, the beam may be either two 2x8s or two 2x10s, depending on wood used. Although the practice is common, there’s no allowance for interpolating beam spans when the joist length you’re dealing with isn’t listed in the table. Numbers in blue are joist spans ( beam to beam or house to beam). Drill through the beam with a long bit the same diameter as the bolts. when the deck joists are 6 ft. long. When the deck joists are 8 ft. long, the beam can span 7-7. Assumes 40 psf live load, 10 psf dead load, L/360 simple span beam deflection limit, cantilever length L/180 deflection limit, No. or 2x12s at 24” O.C. The beam spans are based on the span of the deck joists, which are listed in 2 ft. increments from 6 ft. through 18 ft. Joints in beam layers must fall over posts. DECK BEAM SPAN LENGTHS a, b (ft. - in.) The vertical and lateral load paths of conventional residential decks are addressed in the 2018 International Residential Code. (For more on other aspects of framing an elevated deck, have a look at this guide.). 2 grade, there is a method that can be used for estimating beam spans for a preliminary design. Joists may bear on the beam and extend past the beam face up to the lesser of L O or L/4 as shown in On Center Joist Spacing 12" 16" 24" Overhang? 2 Stress grade, and wet service conditions. dead load and 40 psf. The size of a beam is a function of the amount of weight it must support and the distance it must span. CASE II SOLUTION: Listed are 46 tables based on common loading conditions for floor joists, ceiling joists and rafters. 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. 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. For example, a 2 x 12 joist placed 16” OC. A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on. Deck Beam Span & Footing Size Calculator Deck beams and joists go hand-in-hand as the framing materials for your deck. Beams made of two or more pieces are usually at least as strong as solid beams of the same size. Beam and Joist Span Tables Built-Up Wood Floor Beams Supporting One Floor in a House Maximum Spans for Uniformly Distributed Loads Species and Grade Supported Built Up Beam Size Joist Length 3-2X8 4-2X8 3-2X10 4-2X10 3-2X12 4-2X12 8 9-8 11-2 11 … For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 … For help, simply click on the beside the section you need help with, Or watch this Tutorial Video. live / snow load. Beam Span Chart Learn how to size your deck beam using this easy-to-use span table. 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. The longer the joist, the more area of deck the joist supports, and thus the beam supports. By clicking GO!, you acknowledge that you have read Trex's Privacy Policy. So run the table by your building official for approval before using it. Measurements of deck beam lengths need to be from center of post to center of post. Joist Span – Non-Ledger 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. But keep in mind that most fascia/skirt boards are 11-1/4 in. Simplified maximum span tables for selected visual and mechanical grades of Southern Pine lumber in sizes 2×4 thru 2×12. Your beams will need to bear the load of not only your decking materials, but additional components of the frame itself. You can also use the Wood Beam Calculator from the American Wood Council website to determine maximum rafter and joist lengths. Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features. Hundreds of articles and videos by top deck-building pros on how to design and build a beautiful, sturdy, and safe deck. Most decking is not strong enough to support longer spans than 16". While joists provide a horizontal support system for deck boards, beams provide support for the joists. Fewer posts on upper level decks are typically more desirable to the occupants and this drives the use of larger framing materials for longer spans. Beam span maximums are based on a maximum anticipated live load. Nevertheless, table R507.5, “Deck Beam Span Lengths,” handles this complexity pretty simplistically, representing the load on the beam as the joist span. I like to use this provision when sizing beams. Other (more complex) load condition spans can be determined with our free Hyne Timber Design 7.5 software. Beams are permitted to cantilever past the end posts up to one-quarter of the beam span between posts. wide, which means they aren't wide enough to fully cover both the deck boards and a 2x12 joist. Deck joists shall be permitted to cantilever not greater than one-fourth of the actual, adjacent joist span. Beam Configuration. Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine. Refer to the Deck Beam Span Table below to assist in determining the maximum span of a given beam between posts. With the min. Become a member and get unlimited site access, including the The span of a beam is dependent on a few variables. 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. However, lumber prices are rising and therefore it is more common to see 5/4”x6 deck boards that should not span more that 16” and usually 12”. Obviously, the larger the beam, the greater the distance it can span between posts. Terms of use, How to Create Strong Post-to-Beam Connections, How to Install Deck Girder, Cantilever or Drop Beams, How to Splice a Deck Beam Over a Support Post, How to Use a Triple Deck Beam to 6x6 Post Connection, Understanding Point Loads and Beam-to-Beam Framing. Beams Allowable deck beam span lengths can be determined in MRC Table R507.5. A three-ply 2×12 would allow you to use only two deck support posts for the 10×10 deck. Headers & Beams This allows me to make the beam a little smaller (by dropping, say, from a double 2×10 to a double 2-2×8). *Joists may cantilever up to ¼ of the actual adjacent span. Examples of the flush beams and dropped beams can be seen in the examples shown. 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. "I'm building a ground level deck, maximum 24 inches above the ground, it's L-shaped and it'll have two long beams. Just cross-reference the post spacing and joist length to determine the beam size. These values didn’t change in the 2018 version of the IRC. on-center along both edges. The numbers in gray indicate the distance between the support posts. A common beam is composed of the same size and type of lumber used for the joists by nailing 2 or 3 together side by side. When the deck joists are 8 ft. long, the beam can span 7-7. ICC Digital Codes is the largest provider of model codes, custom codes and standards used worldwide to construct safe, sustainable, affordable and resilient structures. Most decks use 16" on center spacing for joists. Repeat this process at 16-inch intervals across the length of the beam. Build a Grade-Level Deck: Install Posts and Rim Beam, Adding Fascia and Other Decorative Elements, Laying Out, Cutting, and Installing the Stringers, Installing Treads, Risers, and Stair Railings, Expert insights on techniques and principles. The beam table is limited to 10 psf. Building codes for residential decks only require 40 psf. Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs. 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 wood or metal and 3 in. Maximum Beam Spans for Patio Roofs Keep in mind that these are minimums for the spacing indicated—you can select larger sizes to handle excessive loads or for appearance. 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. There are Tables that also provide sizing for beams based on span, joist wood type, and grade, as well as beam size, support post spacing, and footing requirements. 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. © 2021 The Taunton Press, Inc. All rights reserved. For pressure-preservative-treated southern pine no. The beams will be three-ply pressure-treated SP number two 2 by 12s, using 12-foot long lumber cut to … Beam Span Calculator For help, simply click on the beside the section you need help with, watch this Tutorial Video. The maximum joist spacing you can use will depend on the size and allowable span … The species of lumber, size of lumber and the load it carries. Beams must be attached to posts using either post cap hardware or a notched leg of the post. on concrete or masonry. For simple construction, such as domestic construction, this can be determined from span table supplements in AS1684.2 and AS1684.3. Sizing deck beams got a lot easier with the publication of the 2015 International Residential Code. Section R507.6 calls for the built-up beams to be fastened together with a minimum of 10d nails spaced 16 in. spanning 16’-6” between supports may cantilever up to an additional 4’-1 ½” for a total maximum length of 20’ -7 ½” Southern Pine Deck Beam Maximum Spans* View Joist & Rafter Tables. A beam overhang can be a maximum of 3/8 of the supported span. A beam of that size can span nearly 12’ while supporting 10’ joists. Beam ends must bear at least 1 1/2 in. Often I can reduce the span between posts slightly by cantilevering the beam. Copyright © 2021 Trex Company, Inc. All rights reserved. Maximum allowable spans for wood deck joists, as shown in Figure AM106.1, shall be in accordance with Table AM106.1. The farther a deck beam must span—that is, the farther apart the posts are—the more massive a beam must be. Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. Another way to hide the ends is to install a border/perimeter board around the outside edges of the deck (bottom). Deck joist span tables commonly identify the maximum span for different wood types and joist spacing. Joist Spacing for Composite Decking Structural Steel Beam Span Table Posted on April 7, 2020 by Sandra Structural steel hand 2020 steel beam s install support structural steel shapes information part 3 4 structural steel members sizes for steel i beams hss channel The maximum span indicates how long a beam can run supported by two deck support posts. Of course, beefier sizes also increase your lumber bill. Decks Project Guide. A Redwood 4x6 beam should span no more than 6' between … Beam span and cantilever measurements are taken from the center of the posts, not the face of the posts. Deck joists are typically spaced either every 12 inches or 16 inches on center. Deck builders can now refer to Section R507.6 Deck Beams and Table R507.6 Deck Beam Span Lengths to determine the size of 2-ply and 3-ply built-up beams made from 2×6 through 2×12 lumber. Spans for a preliminary design and the distance it can span 10 feet and on... 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Determined with our free Hyne Timber design 7.5 software must support and the load carries... 12 ’ deck span, the larger the beam span maximums are based on size and design! 52 % * joists may cantilever up to ¼ of the joist supports, safe!