Though there are building codes dictating many aspects of deck construction to insure the finished deck is safe and solid, there is no specific distance required for the spacing of screws attaching deck boards to the joists. Make sure to follow the deck board end gapping chart (Page 9, Figure 1) for gapping between the deck boards. I made the mistake years ago of using 600mm centres on iroko, which in itself would have been ok, it was a nice 22mm thick board, but I forgot the customer wanted the boards at an angle, so that increased the span to about 700 from memory, which was still ok for the bounce but it twisted like a pig. Available in many different anodized or powder coated finishes, as well as silver, sand, or gray tone aluminum. The thickness of deck boards and the distance between joists determines how solid your deck will be. For high traffic decks, 2×6 planks offer a more solid and safer surface. How to lay out, place, & secure decking: the deck flooring. The space between the ends of boards should always be 1/8 inch. Deck spacing isn’t anything to take lightly. Even though it is just a simple single step, the box base will need to be secured into the ground – NOT free standing. The load a deck can support is based on the dimensions and spans of the materials from which the frame is constructed. The supports for the decking will be 24" center-to-center. It can also create a trip hazard if it dips too far. Installing double joists where the boards meet in a run takes “pre-planning” – meaning you need to know where the boards will butt and have a double joist installed BEFORE nailing down the decking. 50x30 merbau decking boards (about 22kg/m2) on 120x35 joists spaced at 590mm supported by steel L brackets at intervals of 1450 with M12 bolts it's a low deck (top of boards at 170mm) and the brackets are to be anchored to a concrete slab thanks Deck boards – no matter the thickness (5/4″ or 2″) should always be fastened on top of a DOUBLE joist so there is enough nailing edge on each decking board where they are butted. Cedar deck board spacing … Maximum spans for decking shown in the table are based on a continuous beam with two equal spans and a concentrated load of 220-lb at the center of one span. I hope you have a better understanding of the types of deck boards on the market, and how to choose the right dimension lumber for your deck. Some composite 5/4 deck boards carry recommendations for joists at 12” OC, while others are reinforced with fiberglass and can span joists at 24” OC. Your comments and suggestions are appreciated. Step 1: Mark Line Measure from the house to the inside edge of the starter board and mark both rim joists at this distance. The spacing between standard joists will depend upon the thickness of the actual deck boards. Cedar Deck Spacing Tips. Are you ready to build or resurface a deck but don’t know what deck board dimensions are right for your plan? Holes for deck screws need to be pre-drilled though, making it a bit more work to install. The grade of wood – #1 or #2, premium, or standard determines the price and quality of the wood too. Has a 30-year warranty against staining and fading. So at this time my overall overhang of my border is going to be 1 ½”. Untreated pine, spruce, or fir can be used as decking. spanning 16’-6” between supports may cantilever up to … It was installed on 45 degree angle to 2x10 joists with 16" spacing. Cost may also be a factor and is determined by lumber grade. Select your decking material. Not at all phil, the spacing for decking joists is more about stoping the wood twisting. Deck joists support deck boards and everyone who walks or relaxes on a deck, and whatever is placed on it too. Probably the most difficult decision to make when building a wood deck is what type of decking to use. board will end. Re: spacing for cedar deck boards i have never noticed a difference between rdwd and cedar as for spacing .it was moisture in the boards that was tricky . Deck boards that are laid at an angle to the joist are limited to 12” OC (or less) joist spacing. The wood is either air or kiln-dried, which decreases the moisture content. 5/4 x 6 needs a maximum of 24 inches. He is passionately interested in home improvement, renovation and woodworking. Deck boards that are laid at an angle to the joist are limited to 12” OC (or less) joist spacing. Most building codes limit 5/4 deck boards to maximum joist spacing of 16” OC if laid perpendicular (at right angles) to the joists. To help figure the amount of decking needed for a project, use the following linear footage calculator: Check with your local building authority about what span is required in your area. Use 2×6 planks for 16” or 24” OC joists, or if running diagonally to 16” OC joists. Choices of deck board fastener types and methods include nails, screws, clips, and a wide variety of hidden deck board fastener systems that we describe here as well. As with deck boards, the greater the span and the thinner a joist, the more it will flex and bounce. For 2x material (1 1/2” thick) I’d use 24” spacing for plastic decking boards and 36” spacing for Cedar, Redwood and pressure treated boards. I want to pass building code here in Kentucky. Using screws to attach decking. Is it OK to use 5/4 PT decking on 45 degree angle to 16" spaced joists or should I install at 90 degrees. Are you looking to build the outdoor deck of your dreams but don’t know where to start? Watch this video to get insider tips on how to save big on Western Red Cedar decking. It is recommended you check your local building codes before proceeding. WRCLA Western Red Cedar decking is available in a selection of thicknesses, widths and lengths as shown in the table below. Some builders reduce joist spacing to 12" on center to strengthen the deck frame or to increase maximum allowable joist spans. The two most common deck board thicknesses are 5/4” and 2”. An inexpensive choice that will require cleaning and staining once or twice a year, or a wood-look synthetic polymer that won’t fade, split or mold for 50-years, but costs 10-times more. Most decking is not strong enough to support longer spans than 16". All three choices—5/4 x 6-in. Decking boards provide the finished surface of a deck, keep people from falling through between joists, and support the weight of people and furniture between the joists. To get going I also have an overhang all around the deck of ¾” plus I also have the thickness of my fascia to be installed after the decking and it is also ¾”. 28mm thick deckboards can be laid on joists with 600mm spacing - though for higher level decks, this should be reduced to 500mm centres. If fastening plywood decking, select galvanized 8d (2½”) or 10d (3”) spiral or ring nails. For example, a 2 x 12 joist placed 16” OC. Check the chart below for a quick comparison. Maximum Joist Spacing for Decks Southern Pine Deck Joist Maximum Spans No Cantilever With Cantilever* *Joists may cantilever up to ¼ of the actual adjacent span. Common deck board widths are 4”, 6” and 8”. The primary function is to drain water from the deck. Characteristics & Properties of Western Red Cedar. Additionally, climatic conditions can cause boards to sag over time if the span is too great. Composite deck boards will require the joist spacings to be closer than this. Cedar has unmatched natural beauty that can't be compared to other species or composites. Low maintenance, no warping, cracking or splinters, or any mold, mildew, rot, or UV worries, plus a lifetime guarantee. To use 5/4" decking, requires 16" or smaller spans. The true span of the decking board is used, taking into account the thickness of the supporting joist beneath it. How much joist spacing do you need between your deck framing? Attach 5/4 lumber to joists with the same type of box nail, but use a 10d (3”) or 12d (3¼”) length. Joist spacing is the distance between each joist, and are measured in inches from center-of-joist to center-of-joist. A deck is commonly a platform raised off the ground by posts or blocks that support beams that carry joists that the deck boards fasten to. Choosing between 5/4 deck boards or 2×6 planks may be a personal choice or one based on structural necessity. The size of the deck determines the length of the joists and unsupported span they must cover, and it influences the joist spacing. Whether cedar, pine, spruce, or fir, 5/4×6 deck boards are milled for deck use, while most 2×6 are initially milled as a structural framing material. Shop Top Choice 5/4-in x 6-in x 12-ft Cedar Lumber in the Dimensional Lumber department at Lowe's.com. Larger gaps, such as 1/4”, allow more of this material to fall through the deck. Widths of 1”, 2”, 3” or 4” require more pieces and thus labor to cover the same area. The most common or standard deck board width is 6-inch wide planks based on square-foot coverage, labor, and material cost. A 2”x6” plank will flex more when supported at 24” OC than the other two distances, and a 5/”x6” will flex more at 16” OC than at 12” OC. (2” x 6”x 12’ = $5 to $9), Wood, commonly pine, protected from fungus and insect damage with chemicals that have been forced into the wood with pressure. The stain or sealer should be resistant to UV, mold, and insects. As a rule of thumb, most decks will require 16" on center joist spacing, which means there is 16" from the center of one joist to the other. This is for the homeowners out there that are finally ready to put the finishing touches on their deck (except for stains and sealants of course) and are wondering exactly what cedar deck board spacing to use and why. It is important to note, though, that the thicker lumber dries slower and won’t twist, bow, or cup as much as the thinner material. 5/4 cedar should be installed with a small gap and pressure-treated tight. Dimensional lumber is what is produced by planing the rough cut lumber smooth. The decking should be regularly protected from rot, mold, and insects with a sealer or stain every 2 to 5 years. The plank thickness should provide a solid feel for the unsupported distance between joists. Note: These are nominal sizes, actual sizes may vary by manufacturer. Refer to the Decking Span Table to determine what is the maximum distance that your chosen decking can span between joists. This is easily achieved by building a box frame from the joist timbers (6x2in – 150x50mm) and fixing deck boards to the surface. The distance a deck board traverses between the joists is unsupported, so boards of different thicknesses are required for varying spans. On this deck I wanted one board width as my border and the boards are 5/4 red cedar decking material. But sometimes, they can be a bit unclear when it comes to a crucial component of your deck frame – joist spacing. It is resistant to mold, insects, and rot, and is available in six wood tones. Lay out cedar decking planks in a dry run before cutting Starting from the wall of the house in a parallel run the first board. The bigger the space between the joists, the stronger you need your decking boards to be, as they will have bigger distances in between the support joists they are fastened to. The last board … The decking dilemma—wood deck material options. Once the moisture content is stable, the wood goes through a planer with cutting heads that remove saw marks and smooth the plank surfaces to standard dimensions. Joist spacing. Each deck board must be supported by 4 or more joists for proper performance. A 5/4”x6” deck board is rated for 12” OC and 16” OC, and a 2”x6” plank can span that plus 24” OC. If the board is too thin for the span, it will feel spongy or bouncy. Most decks use 16" on center spacing for joists. Once the frame is complete, you are ready to attach the decking. radius-edged cedar, pressure-treated and composite decking—share similarities. If the planks are too thin for the distance spanned, they will flex and possibly break, and the deck will feel soft or spongy. The spans of joists varies based upon several factors: joist size, spacing between joists, decking material and wood species. They’re all rot resistant to varying degrees, require 16-in. Cedar is more expensive but usually considered to be a more premium looking deck board, it is naturally moisture and rot resistant looks great. A plank spanning too great a distance will flex under load, making it feel spongy, and it may crack or break when bearing weight. The planks are still planed to the same finished or actual dimensions, but more board feet may be produced per log. However, it is best to check with the local building inspector for allowances in your area. Proper deck board spacing should have a 1/8-inch gap after the decking has dried out. Because it's not addressed in the codes, screw spacing is inconsequential. Deck joists are typically spaced either every 12 inches or 16 inches on center. For a 12-foot wide deck, 2×8 southern pine or SPF lumber will span in one length with spacing between the joists of 12” OC or 16” OC, making it a good choice for deck joists. Planks 12” wide aren’t practical due to the cost per piece as they are scarcer as fewer can be milled from a log compared to smaller dimensions. So, depending on what type decking you use, you can the decide what size and spacing of joists to use. Deck joists are commonly 12-inch, 16-inch, or 24” on-center (OC). Joists are commonly spaced at 12” OC, 16” OC, and 24” OC. When you’re finished perusing this article, you should have a better knowledge of deck board dimensions and how to select what’s best for your project. (Figure 2) Step 3: Fasten all deck boards down using 2 T-Clips™ per joist or Dekmount® with at least 2 screws per board per joist. For 5/4 material I’d use a 16” spacing. Set the jig with the tips of the nails on either side of the joists. probable depends on location but a 16p was to small ,I used a 20P for years but seem to be getting bigger lately . In this article, we explain the types of deck boards available, nominal and actual dimensions, board thickness and width, compare 2×6 to 5/4×6 decking, and explore joist span and spacing. The gap will naturally close and widen throughout the year as the weather and seasons change. Some composite 5/4 deck boards carry recommendations for joists at 12” OC, while others are reinforced with fiberglass and can span joists at 24” OC. The widths are readily available in most lumber or building supply stores, and the number of pieces easily calculated into deck dimensions. The grade and type of wood determine the free span it can run – southern pine can span further unsupported than fir, spruce or hemlock, which in turn can span further than cedar. (1” x 6”x 12’ = $60 to $68), Aluminum planks are weather and waterproof boards up to 36-feet in length. Since 5/4×6 have a specific purpose, they are milled smoother and have a more rounded edge to prevent splintering and scuffing. Constant flexing of the plank will weaken it and may cause it to break more easily. Dry material should be spaced a full 1/4 inch apart to prevent damage to the boards as the material absorbs moisture. A nominal or rough cut 2×6 planes down to 1-1/2”x5-1/2” while a 5/4×6 dimensionally is actually 1”x5-1/2”. Beyond that, there … Wet end-use conditions and unseasoned (green) lumber sizes are assumed. (1” x 6”x 12’ = $12 to $20), Composite boards are manufactured from recycled plastic and wood to look like wood. A premium 5/4×6 deck board is often less expensive than a lower grade 2×6 of equal length. They are very resistant to mold, insects, and rot. Decking Joist Spacing. Spacing between deck boards provide a few critical functions. Most of the lumber used to construct the frame is nominal-dimension 2-by timber. First Step: Select a Wood Species . If you install your decking using wet boards, pressure-treated decking that has not yet dried out, then you should install them with no gap as a gap will be created as they dry and shrink. You can literally save thousands of dollars by working with various decking patterns and sizes. One major reason your deck could fail sooner than expected is due to poor framing. The maximum joist spacing you can use will depend on the size and allowable span of your joists… The nominal dimensions of lumber are commonly based on the rough cut size before being planed smooth on all four faces. Western red cedar decking makes a beautiful deck that will last. A 2×6 can span a greater distance, and be used perpendicular to joists up to 24” OC, and diagonally up to 16” OC. Beams are often under the joists but can be part of the joist frame on smaller decks. Joist Spacing for Composite Decking For an 8-foot deck, 2×6 lumber would be ideal. The selection of deck boards is greater today than ever before. Joist spacing is typically referred to as “On-Center” or “OC”, e.g, 16” OC. If you found the article informative or useful, please pass it on to others who may find it helpful. Adjust spacing between deck boards Measure to the house at both ends and in the center when you get within about 5 ft. of the wall. Cost and maintenance, though, are two factors to consider when choosing deck boards. Reading through load tables, it is recommended to use 2x4 or 2x6 stock as the decking, if one is spanning 24". A 5/4×6 can span up to 16” OC when perpendicular to the joists, but only diagonally across joists at 12” OC or less. Eugene has been a DIY enthusiast for most of his life and loves being creative while inspiring creativity in others. Building a deck is a great way to identify your outdoor living space and extend the use and enjoyment of your personal green space. Decking manufacturers may recommend anywhere between 12 and 16 inches for commercial decks and 12 to 24 inches for residential decks. Planks of 8 and 10-inch width are more costly per plank and square-foot coverage than smaller widths and less frequently used. Ideally, the finish gap between deck boards will be between 1/8″ (3mm) and 5/16″ (8mm) but should not be installed at this spacing as 5/4 boards will shrink, increasing the gap. Adjust the spacing between deck boards gradually over the next 10 rows of decking until the distance to the house is equal. The true span of the decking board is used, taking into account the thickness of the supporting joist beneath it. (1” x 6”x 12’ = $60 to $80). Make sure you plan adequate space for your joists. Gaps that are narrow (1/8”), can catch debris, specifically on top of the joists, and can be difficult to clean out. However, selecting the right size board isn’t just a matter of cost; there are other factors to consider too. Start building your next Western Red Cedar project today. But the 2015 IRC included a new one (Table R507.5) that will make it easy for deck builders to spec a joist size for a given span and joist spacing. However, it is best to check with the local building inspector for allowances in your area. Kiln drying allows the rough cut lumber to be cut thinner than 2-inches since it better controls the moisture content. 2 x 6 needs a maximum of 32 inches. By next spring, when the decking is … Cedar should be protected against UV damage with a clear stain or sealer every 2 to 5-years. As it dries, the wood shrinks, especially in width. Greater thicknesses could be used, but increased weight affects the substructure, and greatly increases costs. Wet end-use conditions and unseasoned (green) lumber sizes are assumed. When a tree is cut down and then milled into planks, it is commonly 1 or 2-inches thick with varying dimensions in widths. In writing this, we’re assuming you already have the cedar deck framed up with 16-inch spacing between the joists. Maximum spans for decking shown in the table are based on a continuous beam with two equal spans and a concentrated load of 220-lb at the center of one span. They will gray, weather, and rot quickly if a stain or sealer isn’t applied yearly, or more frequently. Check the distance between joists and select the deck board dimensions best suited for how the deck will be used.