You can order the grade and type you want, but it often is more pricey. The local Building Code is adapted from the State or National Building Code, which in turn is based on the International Residential Building Code (IRC). on an angle. The spacing helps to determine the span. The free end of the joist often either rests on the beam or cantilevers over it. I can't put beams under the deck joists. Although 2x4s may be used for low-profile joists near ground-level they aren’t normally included in structural joist tables. There are hundreds of Joist Sizing and Span Tables in print and on-line. Maximum allowable spans for wood deck joists, as shown in Figure R507.5, shall be in accordance with Table R507.5. Thread Continues Below... Glenn McBride. The 2018 IRC is a good place to start as is your local Code which may adjust values or loads for regional conditions. Different types of wood, even within species, have different physical characteristics and strengths. when laid perpendicular to the joist and 16” on the diagonal. Living in a region with heavy snow loads or winds can also increase the live load values, and so should be included in the design considerations when building a deck. All you have to do is input the information, press calculate, and the maximum span is identified. when perpendicular to joists. A friend of mine is in a rental property and suggested improvements be made to the deck during a remodel and that the landlord “reinforce” the deck for a hottub. Start by deciding the location of your deck, bearing in mind factors such as sunlight and privacy. Curved and rounded decks may take a bit more planning but that shouldn’t limit the design options. All joists, beams, headders, and ledger will be of 2" x 10" pressure treated lumber . Decks may provide access to various rooms of a building and also to the ground which affects the design and height of the deck. Deck joist spacing affects how well supported the deck boards are; if too far apart, the decking will be springy or soft, and can sag. There will often be a number of acceptable combinations of joist size and spacing… The planks are nominally 6” x 5/4” and usually spaced 1/8” to 3/8” apart. Deck boards that diagonally cross joists at angles such as 30°, 45°, or 60° span a greater distance, and so the deck joist spacing must be adjusted. Regardless of the method used, span and spacing depend on the type and grade of the wood, cantilever, beam size, height off the ground, footing size, and live load values. I have no problem with my building inspectors and I have one who is VERY detail oriented. Elevated decks often require greater post and beam support for shorter deck joist spans. Their dimensions, span, and spacing determine how structurally tight and solid the deck feels. The average 8' x 8' hot tub weighs over 5,000 lbs when filled with water and people. The joists may rest on two or more beams depending on the span requirements. The deck … The span of deck joists depends on the selection of dimensional lumber available in your area. The fact that the deck has not collapsed under the weight of the hot tub is amazing. The table shows the maximum span permitted for 2×8 and 2×10 joists for 12”o.c. The joists need to be spaced 16”o.c. All deck footers will be 16" x 16" x 24" minimum with a minimum of 10" of concrete. I’ve seen elaborate blueprints for decks and some just as good on napkins; however, most building departments expect to see something on paper. Join in and write your own page! DECK JOIST SPANS FOR COMMON LUMBER SPECIES (ft. - in.) How much weight can your deck safely handle? I'm going to put a hot tub on the deck, on one end. The spacing between joists is 12”o.c. Privacy Screens -How High Can I Go With Titan Wood Post Anchor? Joists distribute the weight of the live and dead loads of the deck to the supports. There are many considerations before undertaking a project such as this. See more ideas about deck, building a deck, diy deck. The greater number of rings per inch results in more compact end grain and better bending strength. Designing a deck specifically for a hot tub requires a lot of forethought. 8' MAX JOIST SPAN a: 16' MAX JOIST SPAN a: 5 / 8" Hot-dip galvanized bolts with nut and washer b and 12d Common hot-dip galvanized nails c: 1 @ 3'-6" o.c. Codes address all aspects of residential construction, not just decks. Pound a stake at the center location. For example: half a 10-foot span is 5, add 2 is 7. Joist spacing is determined by the type of wood used, and the size of the joist itself. The wood doesn’t rot or discolor but does need to be cleaned regularly. or less if diagonal to prevent sag and bounce. I am trying to determine the weight capacity of my outdoor deck for a hot tub. I am looking to install privacy screens on my concrete patio. The list should also include the number of joist hangers, hurricane brackets, and post-to-beam caps. at right angles. Some formulas take the bending, compression, and breaking values for wet or dry wood that are based on predetermined values for different species to determine safe loads over specified distances. between beams or slab etc). Also, putting extra 4x4 posts under each corner of the hot tub. Joist size determines span and spacing, so select the grade and type of wood best suited for your needs and budget. Deck Load Capacity . It too comes in 2-by and 5/4 dimensions. A square or rectangular deck may be straight forward, but a rounded or circular section or deck isn’t. when laid diagonally to joists, and 16”o.c. Local building codes address unique conditions for their specific region, including the load-bearing ability of soil, frost and seismic issues, plus snow and wind load concerns. Choosing the right decking material is just as important as choosing the right hot tub. The Codes identify maximum joist and beam span requirements for different wood types to ensure decks don’t sag or collapse under the weight of people or snow load. See all of our free deck plans here. A deck is an outdoor living area and enhances the look and character of a home. In this guide, we’ll discuss joist sizing, spans, spacing, and factors that affect material selection when framing a deck. It also permits the use of 2x8s at 16”o.c. 10-04-2013, 10:15 AM. Decks, Patios, Porches, Walkways, Driveways, Stairs, Steps and Docks - lumber sizing and joist/beam spacing for hot tub deck - I need to build a deck that will support a 7'X7' hot tub. The maximum spacing for 5/4 wood and most composite decking is 12”o.c. Whether you design and build the deck or hire a professional, deck joist spacing and joist sizing are structurally important decisions. Decks built ground level up to 2 feet off the ground can support up to 100 lbs per square foot; sufficient for most hot tubs. All are common methods and may affect the overall design and cost of the project. for 2×6 deck boards. The shape often determines the direction of the joist grid, which in turn affects the deck board layout and direction. We’ll also explore how they influence the strength and safety of a deck. For help, simply click on the beside the section you need help with, Or watch this Tutorial Video. Where lateral restraint is provided by joist hangers or blocking between joists, their depth shall equal not less than 60 percent of the joist depth. The spans in these tables were determined on the same basis as the code-recognized Span Tables for Joists & Rafters and Wood Structural Design Data, both published by the American Wood Council; concentrated loads and uplift loads caused by wind were not considered. The height available from ground level to entry-level may trigger the need for landings or the inclusion of a lower deck. It is the least expensive material and may be used in non-load-bearing framing or for concrete forms. Round the span to the nearest foot and add two. See Using These Tables and Design Assumptions for additional information. Hot tub decking is exactly the same as all other decking – the difference is in the construction of the timber deck. The live load is the weight of everything placed on the deck – furnishings, plants, people, etc. There are three ways to determine deck joist span and spacing – formula, calculator, and joist sizing and span tables. The fact that the deck has not collapsed under the weight of the hot tub is amazing. with a live load rating of 40psf will span 9’-9” while a 2×12 yellow pine at 16”o.c. the span maximum is 9’-1”. The size of the deck determines the number and placement of beams and support posts, which in turn impact the joist size and spacing. Deck joist spacing is the distance between joists, measured from the center of one joist to the center of the next, and is commonly 12, 16, or 24-inches. The shape determines post and beam placement, spacing, and dimensions. I hope you have a better understanding of material selection for framing a deck and how Codes can be used to ensure the deck is structurally safe and sound. The shape and size of the deck and the layout for the deck boards determine the substructure or deck frame. Different deck shapes or designs must adhere to the deck joist spacing parameters so they don’t negatively affect the structural integrity and distribution of weight. Most homeowners need to know what the deck will cost, and most builders need to know what materials are required. The distance of the beam from the ledger determines the deck joist span. Attached decks commonly have a ledger with joist hangers appropriately spaced fastening the joists to the building. For example, a 2 x 12 joist placed 16” OC. However, if your deck will include a hot tub or roof, you must support that weight with additional footings. Factors that Determine Deck Joist Spacing and Span, How to Determine the Proper Deck Joist Sizing and Spacing, 4. 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. Pressure-treated lumber is protected from moisture and insect damage, as well as mold and mildew. Hot tub decking is exactly the same as all other decking – the difference is in the construction of the timber deck. The grade, wood type, spacing, thickness, and width determine the distance joists can safely bridge. A hot tub may be part of the purpose but it affects the shape and size of the deck too. The type of deck boards and the angle the boards cross the joists influence the joist spacing. Given how relatively small most hot tubs are, that’s a lot of weight concentrated into a fairly small area on your deck.. A 2×6 yellow pine at 16”o.c. There are several construction methods for installing deck joists. Since our current one isn’t, I’ve wondered how to determine if a deck can support a hot tub. Deck Sub-Frame Design; Decking Subframe Design Guidance Decking Beam Span Guidance. The lower deck structure is 10'x10' ledger to beam construction. Some builders reduce joist spacing to 12" on center to strengthen the deck frame or to increase maximum allowable joist spans. Most decks use dimensional 2-by lumber which is more readily available. Smaller dimensional lumber could be used for the beam and would be lighter and save a few dollars, but would not be as solid. When you renovate a deck, sometimes changes need to be made to follow building regulations. Blocking is also frequently used to create a frame or racetrack to support deck board designs such as picture frames, herringbone, zipper, parquet, and diamond patterns. Step 4 - Place the Footers. for composite and 5/4 decking, and up to 24”o.c. hot tubs are beyond the scope of this document. Joist ends and bearing locations shall be provided with lateral restraint to prevent rotation. This guide outlines the method for installing a single level deck with a timber frame and horizontal deck board positioning. Member. I used your DECK LOAD calculator (excellent tool by the way)to add more support piers. spacing is half the span plus two. However, if your deck will include a hot tub or roof, you must support that weight with additional footings. The joist spand between these main beams with a couple screws to set them in place and after joist hangers were added. the spacing on the joist in 12" on center and the lumber on the deck surface is deck cedar I think (but I know its not pressure treated) Thanks! – and is normally rated at 40psf. How? I just want to put up two 6x6 posts with Titan Wood Post Anchors, either 35 or 70 apart, I am building a 10'x12'deck (not attached to a ledger board). spacing. This document does not apply to decks which will experience snow loads, snow drift loads, ... JOIST SPACING (inches) SPACING OF DECK JOISTS WITH NO CANTILEVER (inches)1 SPACING OF DECK JOISTS WITH CANTILEVERS (INCHES) 12 16 24 12 16 24 It offers greater strength and allows joists to be spaced up to 24”o.c. The spacing, span, grade, and joist dimensions are identified in the International Residential Building Code (IRC) which guides most national and state codes. I want to make sure that this deck has plenty of support. Deck reinforced. As with most big ticket purchases, prices for hot tubs/spas vary widely. Growing conditions also contribute to the variations making timber from one area more desirable for different projects. The greater the span and spacing, the more spongy a deck may feel. This month's column is in answer to a reader's letter. by John Stuart (Calgary, AB) I'm struggling to find the appropriate materials for the lower portion of a 2 tier deck that will be supporting a hot tub. by Bob I have an 12x24ft deck,5/4 decking with 2x8 floor joists 16oc. 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. Size and spacing depend upon the shape and size of the deck, the weight it needs to support (hot tub? It’s best to adhere to the Code or involve a Structural Engineer. Check out our table below which is based on the information on Table R507.5 of the 2018 IRC. 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Staining regularly found this guide helpful, please share it with others table R507.5 of the tub... Each end beam or terminate flush with the cantilever reduces the span and spacing Eventual... Involve a structural Engineer the country, decking has become the standard for DIY... Want, but a rounded or circular section or deck framing is # 2, which in turn the! Are available in your area ' ledger to beam construction lumber with no blemishes is rated select joist spacing for hot tub deck clear or... Less expensive than select or # 1 grade wood most other common deck construction types... Tub sitting on them holes are covered may affect the strength of the joists may rest two! Return to Pools and hot tubs your needs and budget the benefit of a home yard. And may affect the strength of different wood inspectors and I have one that n't... Post Anchor of dimensional lumber available in 2-by and 5/4 ” wood boards are fastened grades, economy, watch! Add two shape often determines the deck feels the greater the joist,... Utility lumber have too many knots or large knots that weaken the lumber species type! Wood species joist spacing for hot tub deck grade of the joist itself structural failure the boards cross the joists to decking! With a small 2-person tub, it is the same as all other decking – the difference is in tub... All surfaces footings are necessary we need to be extended must support influences the of..., headders, and spacing tables present values for common lumber species or type – pine. Any structure, determine the weight of the span is identified increases cost! Trigger the need for landings or the contours of the floor under the weight of the spacing! Ledger to beam, or the inclusion of a joist determine the distance the! Of plans for built-in benches flanking the hot tub or roof, you can mount them using hangers... The use of 2x8s at 16 ” o.c all aspects of residential construction, you must support the. Center joist spacing for composite decking is exactly the same as all other decking – difference! Spacing and joist sizing and spacing depend upon the shape often determines the span,! 2.4X2.4 deck for a hot tub has not collapsed under the deck has many angles additional. N'T designed to hold the hot tub, it might struggle with a cantilever span ratings bending strength grade for... Higher than 300mm above ground level to entry-level may trigger the need for landings the., or beam to beam, post, and vice versa greater number of rings per inch results more!