Start your subscription today and save up to 52%. The vertical and lateral load paths of conventional residential decks are addressed in the 2018 International Residential Code. Beam ends must bear at least 1 1/2 in. Examples of the flush beams and dropped beams can be seen in the examples shown. Beams are permitted to cantilever past the end posts up to one-quarter of the beam span between posts. "I'm building a ground level deck, maximum 24 inches above the ground, it's L-shaped and it'll have two long beams. Nevertheless, table R507.5, “Deck Beam Span Lengths,” handles this complexity pretty simplistically, representing the load on the beam as the joist span. on-center along both edges. Beams must be attached to posts using either post cap hardware or a notched leg of the post. 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. 2 Stress grade, and wet service conditions. (For more on other aspects of framing an elevated deck, have a look at this guide.). A double 2x12 beam can span 12 feet; a (2) 2x10 can span 10 feet and so on. Home > Joist Span Calculator. Building codes for residential decks only require 40 psf. But you’ll notice when you look at the portion of the span table for joists with cantilevers that the joist span for decks with a cantilever is often less than the span for the same sized joist without cantilevers. 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* For example 2x6 materials can usually span 24” without any noticeable deflection and still support a significant load. With the min. DECK BEAM SPAN LENGTHS a, b (ft. - in.) One is 27 and a half feet, the other one is 31 feet. 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. Simplified maximum span tables for selected visual and mechanical grades of Southern Pine lumber in sizes 2×4 thru 2×12. The beam table is limited to 10 psf. This allows me to make the beam a little smaller (by dropping, say, from a double 2×10 to a double 2-2×8). 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. Become a member and get unlimited site access, including the Another way to hide the ends is to install a border/perimeter board around the outside edges of the deck (bottom). On Center Joist Spacing 12" 16" 24" Overhang? 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. Section R507.5 notes that deck joists can cantilever up to 1/4 of the joist span. Building codes for residential decks only require Beam Span Chart Learn how to size your deck beam using this easy-to-use span table. 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. For pressure-preservative-treated southern pine no. Drill through the beam with a long bit the same diameter as the bolts. wood decks focusing on the significant changes for the 2018 IRC. 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. 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. 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 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. The farther a deck beam must span—that is, the farther apart the posts are—the more massive a beam must be. ICC Digital Codes is the largest provider of model codes, custom codes and standards used worldwide to construct safe, sustainable, affordable and resilient structures. The longer the joist, the more area of deck the joist supports, and thus the beam supports. The calculations below list approximate recommended deck beam spans. Joints in beam layers must fall over posts. Beam span maximums are based on a maximum anticipated live load. or 2x12s at 24” O.C. 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 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. Deck joist span tables commonly identify the maximum span for different wood types and joist spacing. Deck joists are typically spaced either every 12 inches or 16 inches on center. Repeat this process at 16-inch intervals across the length of the beam. For simple construction, such as domestic construction, this can be determined from span table supplements in AS1684.2 and AS1684.3. I like to use this provision when sizing beams. Hundreds of articles and videos by top deck-building pros on how to design and build a beautiful, sturdy, and safe deck. Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine. When the deck joists are 8 ft. long, the beam can span 7-7. While joists provide a horizontal support system for deck boards, beams provide support for the joists. Some builders reduce joist spacing to 12" on center to strengthen the deck frame or to increase maximum allowable joist spans. Deck Beam Span & Footing Size Calculator Deck beams and joists go hand-in-hand as the framing materials for your deck. Joist Span Calculator. *Joists may cantilever up to ¼ of the actual adjacent span. Use the Beam Size table and find the 8’ post spacing column. You can also use the Wood Beam Calculator from the American Wood Council website to determine maximum rafter and joist lengths. Of course, beefier sizes also increase your lumber bill. For example, a double 2×8 beam can span 8-ft.-0 in. Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. Obviously, the larger the beam, the greater the distance it can span between posts. Beam span and cantilever measurements are taken from the center of the posts, not the face of the posts. These values didn’t change in the 2018 version of the IRC. Beams Allowable deck beam span lengths can be determined in MRC Table R507.5. The maximum joist spacing you can use will depend on the size and allowable span … Use the span tables below to determine allowable lengths of joists and rafters, based on size and standard design loads. The beams will be three-ply pressure-treated SP number two 2 by 12s, using 12-foot long lumber cut to … A beam overhang can be a maximum of 3/8 of the supported span. 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. 2 grade, there is a method that can be used for estimating beam spans for a preliminary design. wide, which means they aren't wide enough to fully cover both the deck boards and a 2x12 joist. Headers & Beams A Redwood 4x6 beam should span no more than 6' between … Floors (Decking and Joists) Metal decking with shear studs, 2” deep spans 10’, 3” spans 15’ in the direction of the decking ribs. Assumes 40 psf live load, 10 psf dead load, L/360 simple span beam deflection limit, cantilever length L/180 deflection limit, No. A three-ply 2×12 would allow you to use only two deck support posts for the 10×10 deck. Refer to the Deck Beam Span Table below to assist in determining the maximum span of a given beam between posts. Deck joists shall be permitted to cantilever not greater than one-fourth of the actual, adjacent joist span. Your beams will need to bear the load of not only your decking materials, but additional components of the frame itself. Often I can reduce the span between posts slightly by cantilevering the beam. View Joist & Rafter Tables. Just cross-reference the post spacing and joist length to determine the beam size. 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. For example, a 2 x 12 joist placed 16” OC. So run the table by your building official for approval before using it. The size of a beam is a function of the amount of weight it must support and the distance it must span. on concrete or masonry. © 2021 The Taunton Press, Inc. All rights reserved. CASE II SOLUTION: when the deck joists are 6 ft. long. But keep in mind that most fascia/skirt boards are 11-1/4 in. For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 … Decks Project Guide. With a 12’ deck span, the beam may be either two 2x8s or two 2x10s, depending on wood used. Beams made of two or more pieces are usually at least as strong as solid beams of the same size. 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. The numbers in gray indicate the distance between the support posts. The span of a beam is dependent on a few variables. Beam Configuration. on wood or metal and 3 in. live / snow load. 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. Most decking is not strong enough to support longer spans than 16". 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. Beam Span Calculator For help, simply click on the beside the section you need help with, watch this Tutorial Video. By clicking GO!, you acknowledge that you have read Trex's Privacy Policy. Specific design guidance includes convenient span tables for joists and beams and charts of post sizing limitations and connection methods. Sizing deck beams got a lot easier with the publication of the 2015 International Residential Code. 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. For help, simply click on the beside the section you need help with, Or watch this Tutorial Video. Measurements of deck beam lengths need to be from center of post to center of post. 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. 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. 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. 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. When the deck joists are 8 ft. long, the beam can span 7-7. Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features. dead load and 40 psf. Lumber Species Southern Pine Douglas Fir Douglas Fir-Larch Hemlock-Fir Spruce-Pine-Fir Redwood Western Cedar Ponderosa Pine Red Pine Joist Spacing for Composite Decking Beam span maximums are based on a maximum anticipated live load. Listed are 46 tables based on common loading conditions for floor joists, ceiling joists and rafters. 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. The maximum span indicates how long a beam can run supported by two deck support posts. Joist Size 2x8 2x10 2x12. Lumber Species. 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”. When a joist spans from a ledger to a beam, half the length of the joist is loaded on the beam, and this uniform loading is the basis of the engineering in the table. A beam of that size can span nearly 12’ while supporting 10’ joists. The species of lumber, size of lumber and the load it carries. Other (more complex) load condition spans can be determined with our free Hyne Timber Design 7.5 software. Numbers in blue are joist spans ( beam to beam or house to beam). Span tables allow users to choose an appropriate size and stress grade to achieve spanning needs. 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 … Most decks use 16" on center spacing for joists. 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