Use a joist span table such as those found in the Resources section to determine the maximum 2-by-10 joist spans for other species and lumber grades. Joist Span Calculator. See the notes below the span tables for details. The lengths and sizes of joists vary depending on the species and quality of the lumber used. Deck Joist Maximum Spans No Cantilever With Cantilever* *Joists may cantilever up to ¼ of the actual adjacent span. The spans are based on simple-span joists. We recommend beams are constructed from two 44 x 145mm Q-Deck deck joists and are placed at maximum centres of 1.8m. If adding additional framing, be sure to keep all boards level and in plane across the tops. Wood Beam Calculator (American Wood Council website) Rafter and Joist Span FAQ. A triple 2x6 beam over a span of 10' feet should be more than sufficient for normal deck loads. That all depends on the length of the clear (unsupported) span the joists have to make. A ... For example, my local code (IRC) specifies that the maximum allowable span for a 2x8 joist depends on the spacing of the joists (which you did not mention in your post), and the species of wood (which you did not mention in … Use the Beam Size table and find the 8’ post spacing column. 2” X 6”. o.c. Decking boards span from joist to joist. Refer to the Decking Span Table to determine what is the maximum distance that your chosen decking can span between joists. JOIST SIZE JOIST SPACING MAXIMUM SPAN. Table 4-8 Maximum Spans for Deck Joists in ft-in 1: Joist Sizes: 2x6 Joists : 2x8 Joists: 2x10 Joists: 2x12 Joists: Joist Spacing : 12 in. Again, it's important to know your local codes. View Joist & Rafter Tables. Headers & Beams. In this instance the maximum span between deck post centres is 2.07m (C16) or 2.24m (C24). CASE II SOLUTION: If you have an attic over your garage, these joists also bear the load of your attic flooring and any materials you store in the attic. Table 1 Floor Joists – 30 psf live load, 10 psf dead load, 360 deflection . 19.2” “ 8’- 7”. Floor Joist Span. For example, a 2 x 12 joist placed 16” OC. from Span tables of 2009 IRC 2x6 maximum span 9'-4" 2x8 maximum span 12'-3" 2x10 maximum span 15'-5" 2x12 maximum span 17'-10" for 16' span I'd probably go with 2x10 at 12" o.c. So the house dimensions will now be 24' X 13'. For example, a joist made from doubled 2 x 6s can span a distance about 25 percent more than a single 2 x 6, but a 2 x 12 can span about 80 percent more than a 2 x 6, even though it has the same amount of wood as a doubled 2 x 6. Floor joist span tables for surveyors – Floor construction. Listed are 46 tables based on common loading conditions for floor joists, ceiling joists and rafters. o.c. Maximum Spans. (on center). This a rough guideline. The rule of thumb is 6-foot span with a 2×6 on 16” centers. Your selection of decking material will determine the maximum spacing of your joists. FLOOR JOIST TABLE. Joists & Rafters. Span Tables for Domestic Floor Joists (to BS 5268-7.1) Note: Our floor joist span tables are based on loadings given in the newer, amended version of BS 6399-1. Douglas fir - Larch: 10-9: 9-9: 8-3: 14-2: 12-9: 10-5: 18-0: 15-7: 12-9: 20-11: 18-1: 14-9: Hem-fir: 10-0: 9-1: 7-11: 13-2: 12-0 Wood Species: o.c. The width is considerably more important than the thickness of a board. The lowest is a plain ceiling joist with no storage (10 pounds per square foot). o.c. 16 in. 2 grade, there is a method that can be used for estimating beam spans for a preliminary design. 16”“ 9’- 1”. the deck is typical construction. Select a load. Here's a helpful chart covering the most popular wood framing species and their maximum allowed spans: Composite Deck Joist Space. 1. for Southern Pine . - If supporting lightweight partitions running parallel to joists, provide two additional joists under each partition. 12 in. with a deflection of L/360 you could expect the following deflection = (16'x12" per ft)/360 = 0.53" also available for the Android OS. Summary The span of a 2x6 beam depends on several variables including the size, type, and species of lumber as well as the load. Read on and learn a little bit about what affects your decking's strength - like material and joist spacing. weight of the spa filled and 5 adults is listed at 3500#. Simplified maximum span tables for selected visual and mechanical grades of Southern Pine lumber in sizes 2×4 thru 2×12. Deck Sub-Frame Design; Decking Subframe Design Guidance Decking Beam Span Guidance. 2×6 joists 24″ oc, spanning 10′. o.c. Floor joist spans have been limited to a maximum of 4.2m. o.c. The wooden joists or beams over your garage help hold your roof in place. Ceiling Joist Span. Provide 1 row of noggins to centre of joist spans of 2.5m or greater, and generally at max 1.2m centres for larger spans. o.c. Let's expand our house beyond that 17'2" span capability to 24 feet wide. 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. Two-by-twelve Douglas Fir joists spaced 12 inches apart on center, for example, can span 20 feet, 7 inches, but the same joists spaced 24 inches part can only span 14 feet, 7 inches. 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 11-10 … 2×6 boards across the joists. The highest is a fully loaded floor (70 pounds per square foot). o.c. I need to repair/ reinforce a deck at my sons house. Dense elect Structural Select Structural NonDense Structural No.1 Dense No.1 NonDense No.2 Dense NonDense No.3 12 The widest span in the floor joist span table in Part 2 of this tutorial module showed that floor joists can span 17'2" if they are 2 X 12s spaced 12" o.c. 2x6 or 2x8 for deck joist. 24 in. Please select a length and a quantity and our calculator will do the rest. o.c. 16 in. Longer spans can be calculated as appropriate - Spans less than 1.0m have been omitted. o.c. 24 in. Maximum spans in feet-inches. This means that some values are slightly more conservative than span tables from other sources if those do not include the amended guidance. Without that number, this question cannot be answered as asked. For example 2x6 materials can usually span 24” without any noticeable deflection and still support a significant load. Decking made of 2x4s or 2x6s can span up to 24 inches. Select the on center spacing for the joists. supported by 4×8 beams at both ends. 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”. 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 … If you need a storage area above your garage, strong ceiling joists are necessary to support the added weight. The minimum bearing length is 1 ½”, spans values in bold indicate that web stiffeners are required at the OSB end panel. o.c. 12 in. 16 in. o.c. With a 12’ deck span, the beam may be either two 2x8s or two 2x10s, depending on wood used. Effective June 1, 2013 . Deck joist spacing for composite decking remains largely the same as if working with treated lumber. FLOOR JOIST TABLE. the deck and spa were here when my son bought the house. For a more rigid feel, 12” or less may be preferred. Deck joist spacing should never exceed 16” on center (with the exception of MAX deck boards, which allow for maximum 24" on center). Spaced at 12 inches, the joist may only span 16 feet 8 inches. o.c. or 2x12s at 24” O.C. I joists installation and handling attaching railing post to a 4x8 beam and flush 2x8 joist deck unit attaching pergola posts to deck beams joists building stronger post to beam … However, when running SPF 2×6 floor joists into the floor joist calculator referenced above, you get a maximum span of 9 Feet 8 inches with a minimum bearing length of 3 inches at each end on 12” centers. Size S. Spacing In. 24 in. 12” ON CENTER. There are six choices. If I sister a 2x8 to each 2x6, meaning that the bottoms of the joists line up but the top of the 2x8 is approximately 2 inches above the top of the 2x6…is there a span table for such a situation, or any rule of thumb for estimating strength as per code? At 16 inch spacing, 15 feet 2 inches and 13 feet 3 inches at 24 inch spacing. lumber appears to be doug fir. This is how far apart they will be. Roof Rafter Span. If you use 5/4 decking, joists must be no farther apart than 16 inches. Annotated decking diagram. which has a span of 17'-3", either that or reduce the span. Cantilever Treated & Graded Decking Joist (6" x 2") Stress graded to C16 this timber is well suited to all structural applications. will provide more support, strength, and improved floor assembly compared to 2x4 of the same grade and species. 12 in. Jump to Latest Follow 1 - 6 of 6 Posts. Assume that I have an attic which currently has 2x6 joists on 16-inch centers. 24”“ 7’- 11”. The 2×4’s and 2×6’s are considered to be in SPF #3/stud and the 2×8’s and 2×10’s, in SPF #1/#2. How far can a double 2x6 beam span? Most lay outs are on 16″ so the field is pre-selected. 10’ - 0”. The decking span you choose will affect the feel and potentially the safety of your deck. Span Calculator for Wood Joists and Rafters also available for the Android OS. 24 in. This 6" x 2" is a perfect way to start your new Deck, strong and easy to work with you won't need a professional! If you will run decking at an angle, you might need to put the joists closer together. 16 in. Surveyors and structural engineers use data from tables below to help calculate the size of timbers necessary to … For example, 2x6 joists that are spaced 24-inches o.c.