First, the IRC only allows certain dimensional lumber to be used for deck beams. 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). the midway point between the supported ends (either a ledger or beam) of Most decks use 16" on center spacing for joists. Maximum 2x6 Deck Joist Span To provide support for the joists, deck beams must span the entire length of the deck. For Beam 1, use a joist length of 13’, (6’+7’) and a post spacing of 9’. Lumber Species Southern Pine Douglas Fir Douglas Fir-Larch Hemlock-Fir Spruce-Pine-Fir Redwood Western Cedar Ponderosa Pine Red Pine That is a fairly simplistic way of looking at it. Refer to the Deck Beam Span Table below to assist in determining 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. Figure 1B. Beams rest on and secure to Code compliant and spaced deck posts and footings for support. up to a point. Refer to Table R507.5 of the 2018 IRC for specifics. You should also know the size of the post you are considering to you already understand the relationship between joist span and joist 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 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. For Beam 2, use a joist length of 7’ and post spacing … A deck beam is a board or collection of boards that support the deck joists and decking. Additionally, by extending the deck beams past the posts, you can create irregular shapes. The majority of composite deck board brands including Trex, TimberTech, and more require deck joists spacing to be at 16 inches O.C. Beams are made out of a variety of treated dimensional lumber. (on center) for standard straight composite decking installation. 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. 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 … So, rather than using a 6×6 beam, this would mean using three 2x6s bolted together. 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. The beams are (3x)2x6x16 glued and screwed together. This distance is half the distance to the next beam in either direction. If a joist spans between two beams. Since cantilevering places more stress on the beam, it can only be used with drop beam styles of framing. The span is the distance a joist traverses from ledger to beam, or beam to beam, without support. 5/4 x 6 pressure-treated decking may be placed with each board flush against the next; natural shrinkage will provide the proper spacing. Drop beams are also stronger than flush beams because they rely on the wood structure to support the weight rather than metal fasteners. The greater the joist span, the less distance the beam can span. 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. The Joist span table below is for joists with a continuous span on a deck below 1metre in height. Whereas a 10 feet can span up to 6 feet 6 inches. 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. 2" thick deck boards should be spaced approximately 1/8"; most builders set a 16d nail between the boards as they fasten them. I am looking to install privacy screens on my concrete patio. The narrower the spacing between joists, the greater the span can be. Lumber Species Southern Pine Douglas Fir Douglas Fir-Larch Hemlock-Fir Spruce-Pine-Fir Redwood Western Cedar Ponderosa Pine Red Pine 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. your planning stage, don’t forget to consider the spacing for your 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. 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