You can now verify the locations by measuring from center point to center point. Decks more than 2’ above grade shall be provided with diagonal bracing. For decks with grip-type or side-mounted hidden fasteners for decking-to-joist connections and with any post height greater than 2.5 feet (measured from the top of the footing to the underside of the supporting beam), install 2x6 bracing to the underside of the deck joists per the requirements below. Starting with your perimeter, mark the location of each deck post to locate the fitting position. It needs a complete set of perimeter footings since it will be self-supporting and won’t tie into your home’s existing foundation. Using Decks.com footing layout plans and (2) 50’ cloth tape measures, you can measure the specific dimensions from each of these endpoints to the centers of each footing. The maximum spacing of a pier shall be 10’-0” (3m) Minimum 28” x 28” footing is required for pier spacing that exceed 10’-0” (3m) Maximum Allowable Load Per Footing, in Lbs, Copyright © 2021 Trex Company, Inc. All rights reserved. 3. 2. To make it simple, place your posts no further than 8’ apart. The flat part at the bottom must be at least 6" thick. Figure 2. The size and spacing of footings tie directly to the maximum spacing between posts of the beam they support. With this in mind, the depth of the joist determines the spacing of the beams. (See sections 4 and 5 for determining post spacing and joist length.) To calculate the load, you should use 40lbs per square foot for live loads (these are variable loads that are dynamic such as the weight of people and furniture) and 15 lbs per square foot for dead loads (this is the weight of the materials used for the construction of the deck) for a total load weight of 55 lbs per square foot. If the footing locations appear out of line, you should double check that your tapes are level and that the stationary points match the footing layout drawing. Sample footing detail 1-1/4” to 2” dia. How to Build a Deck on Sloped or Uneven Ground. The more the better though, 6' is where I would go If the deck may be converted to a porch in the future, it is recommended to size the footings accordingly. Use the Beam Size table and find the 8’ post spacing column. If you multiply the area of this section 5’ x 5’, you will get 25 square feet. We will also show you how to decide the number and spacing of your footings. More importantly I was going to use the Deck Foot Anchor for all the outer footings. You must keep your lines or tapes level in order to avoid distorting the shape of the deck in a three dimensional space. A 2×6 joist can span up to 9 feet, a 2×8 can span up to 12 feet, and a 2×10 can span up to 15 feet. Concrete must be used and must have a minimum compressive strength of 3,000 pounds per square inch. In order to determine the proper size for your footings, you will need to establish how much total weight they are going to have to support and what kind of soil they are covering. footing. The American Wood Council publishes the Prescriptive Residential Wood Deck Construction Guide, which is based on the International Residential Code (IRC). The beam may be two 2x8s. 12’ span, 2x8s at 12” O.C., 2x10s at 16” O.C. This is a common rule for footing so don't forget that. continuous full length of stairs 1-1/2” clearance Handrail 4” sphere cannot pass between balusters, under the bottom of the rail, or between stairs at risers. Can or should I use 2x6 spaced a foot apart or 2x8 spaced 16 inch on center. For most situations, you will want to place footings and posts less than 8' apart. It usually helps to have the ledger board installed to give you two fixed positions at the house to work off of. How to Build a Deck on Sloped or Uneven Ground. Joist Span – Non-Ledger Deck. Live or Ground Snow Load (psf) Tributary Area (sq. Determine what size deck beam you need based on your support post spacing, as well as the proper concrete footing diameter, with our beam span calculator at Decks.com. Adjust building width or post spacing to reduce load. 6” min Size your deck beams and headers with our easy-to-use span table, which allows you to cross reference the post spacing and joist length to determine the right deck beam size. Use a footing triangulation drawing to locate your footings based off of two known points along the house wall. If your tapes are held level and when you pull these tapes tightly together, you will form a precise triangle directly above the center points of the footings. Terms of use. First, draw a line dividing the deck into two halves between the house and the footings. This will also increase the costs of construction. ft Red arrows = distance between posts Blue Arrows = distance between beams/overhang Dotted lines = Trib Area of each post/footing designing your deck, read this publication thoroughly and pay close attention to each applicable detail. SECTION 2: FOOTINGS, AND POST CONNECTIONS Footings must comply with all of the following: 1. To make it simple, place your posts no further than 8’ apart. Copyright © 2021 Trex Company, Inc. All rights reserved. Wood Deck Guide PERMIT(S) – WOOD ... Post holes to proper depth, correct spacing, solid bearing and concrete in place. Use the Joist Span table to find the acceptable joist sizes for a. Once you have your joist span, and pier spacing you can size each component of the deck using Tables 1 and 2 below. How far apart should deck joists be spaced? The larger the beam and footing size, the fewer footings that are required. If you are planning on installing a hot tub or porch on top of your deck, you will usually need more footings and posts to support the additional loads. When you excavate your footings you will need to dig below the frost line. The most confusing part about understanding how far apart to space your joists is understanding the chart that explains it. The more the better though, 6' is where I would go stair, pier spacing, joist span and maximum height of the deck above grade. Some builders position them every 4 feet for a completely rigid frame. Laying out footings is usually a two-person job. Joists spaced the standard 16 inches apart can span 1.5 times their depth in feet. 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. In general, posts should be spaced no more than 8 feet apart. You may be able to reduce the number of footings if you use an engineered beam and increase the size of your footings. The maximum joist spacing you can use will depend on the size and allowable span of your joists. O.C. Footing larger than 24” is required. You will need a cloth tape measure, some wooden stakes and a roll of twine. wood decks focusing on the significant changes for the 2018 IRC. How Many Footing Do You Need For Your Deck? field guide sample Sizing Deck Footings Assuming a minimum soil bearing capacity of 1,500 psf, 8-inch-diameter concrete piers bearing on square footings measuring 2 feet on a side and 9 to 11 inches thick are adequate for most single-story decks where beams are spaced 14 feet apart or less and joist spans are 14 feet or less (see table below). A comparison of the footing sizes I calculated for the example deck resting on 1500 psf soil in the Sizing Deck Footings article and DCA 6 Table B3 shows an almost identical result. This works well for square decks, but it can get kind of dicey with irregular shapes like octagons. Joist spacings for 19 mm thick boards must be at 450 mm centres maximum and 600 mm centres maximum for 32 mm boards. For Beam 2 and footings use a joist length of 7 feet and post spacing of 8 feet. For most situations, you will want to place footings and posts less than 8' apart. Can I reuse the footings from my old deck for a new deck project? You will need an open space to work in, and you must move anything that will interfere with your lines or tapes in the site area. Joist Span – Non-Ledger Deck. For example, if it's just a walking area and nothing else, 8' is the furthest you go apart. The maximum distance between footings is determined by the size of your joist material. a smaller diameter than listed in theMinimum Deck Footing Size Table above. Try to keep the string level at least a foot off of the ground. You can start here in order to lay out the perimeter of your deck by tying string between 1x2 wooden stakes set perpendicular to one another. For Beam 2 and footings use a joist length of 7 feet and post spacing of 8 feet. Build — Timber decks — 9. Proper deck post spacing follows the deck post spacing chart that is found within your local building code. Firstly I only have 10-1/2 inches of height to the bottom of the door. By clicking GO!, you acknowledge that you have read Trex's Privacy Policy. Use 6×6 deck support posts and an 8” or 10” wide 3-ply beam. With these style of deck footings … If deck table and chairs where many people will be sitting, then 5-6' apart. Check out our deck footing frost map to help you understand how deep your footings will need to be excavated. Deck joists are typically spaced either every 12 inches or 16 inches on center. Deck plans are approved on the assumption that the deck will be used only as a deck for the life of the structure. The remaining half of the deck will again be split into two parts to be supported by the two corner footings. The wide majority of decks and deck frames built in the United States feature pressure-treated lumber as the deck framing material. Layout and Footing Locations. the deck. 90 x 45mm 1.15M 1.00M 140 x 45mm 1.85M 1.60M 190 x 45mm 2.50M 2.15M 240 x 45mm 3.15M 2.70M 290 x 45mm 3.80M 3.30M When you rest each joist on the stringer on the side of the house foundation wall, leave a 12mm gap between the end of each stringer and the wall. If you are planning on installing a hot tub or porch on top of your deck, you will usually need more footings and posts to support the additional loads. Figure 2. The spacing depends on the load up top. You will notice that the support post is also embedded deeply into the concrete and extends no closer than say 4" from the bottom of the footing. For most situations, you will want to place footings and posts less than 8' apart. can determine how much surface area of the deck that post and footing will carry. 20 feet (width of deck) House 1 4 2 3 5 6 15.5 feet (Projection of deck) 1.5 feet 2 8 feet8 feet 2 feet 8 feet 6 feet TA= 8’ x 7’ = 56 sq. ft Red arrows = distance between posts Blue Arrows = distance between beams/overhang Dotted lines = Trib Area of each post/footing Use 6×6 deck support posts and an 8” or 10” wide 3-ply beam. Deck Types Floating Deck. PRESCRIPTIVE RESIDENTIAL WOOD DECK CONSTRUCTION GUIDE 5 American Wood Council Figure 1B. That stops moisture becoming trapped and causing decay. With a 12’ deck span, the beam may be either two … The current design of your deck requires a footing larger than 24" diameter. The larger the beam and footing size, the fewer footings that are required. 20 feet (width of deck) House 1 4 2 3 5 6 15.5 feet (Projection of deck) 1.5 feet 2 8 feet8 feet 2 feet 8 feet 6 feet TA= 8’ x 7’ = 56 sq. Some of our articles focus on the various types of accepted footings that are used by professional deck builders. Remember that the dimensions on your plan are drawn in two dimensions. What is the Proper Deck Post Spacing. The weight load of your deck also affects the spacing of the posts. It is important that you indicate on you plans the desire to convert the deck at a future date. The spacing depends on the load up top. The size of footings supporting piers and columns shall be based on the tributary load and allowable soil pressure in accordance with Table 1 below. This is called the tributary load. Joist Span – Joists Attached at House and to Side of Beam. Decks with a lot of angles may also require additional footings. can determine how much surface area of the deck that post and footing will carry. 2x10s, depending on wood used. The vertical and lateral load paths of conventional residential decks are addressed in the 2018 International Residential Code. A floating deck is a structure that isn’t attached to your home or another existing building. The load for the section nearest the house will be transferred back to the ledger board and carried down to the house foundation. Drop a plumb bob from the corners of your ledger board and set two stakes next to the house. a Example: a=12’; Post Spacing=8’ y 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. My calculations came up with 15 3/4 in. You will need to work off of two fixed points along the house, the distance between which will form one side of your triangle. diameter center footing size and Table B3 calls for a 16 in. If the footing locations are square, you can prepare to dig. For example, if you are building a 10x10 deck attached to a house with two footings on the corners, you could calculate the loads for the footings in the following way. spacing per detail1/s08 2" min 3/4" min 5 1/2" min for 2x8 6 1/2" min for 2x10 7 1/2" min for 2x12 flashing between deck and exterior wall per detail 1/s04 g lateral load connection per detail 1/s04 or 2/s06 b deck joist per detail 1/s07, typ c deck beam per detail 1/s09 d deck post per detail 2/s09 f deck ledger fastening per details 1/s08 and 2/s08, There are two principal methods for accurately laying out the footing locations based on your plans. A larger beam can span a greater distance, requiring fewer but larger footings. Once you know the total load, you can use the chart below to determine the footing size for your soil conditions. According to our beam span chart resource, the span of a beam is dependent on a few variables: the species of lumber, size of lumber, and the load it carries. Composite decking boards are available in a range of widths and thicknesses similar to timber and in lengths between 4.8 … In lieu of using this table, another option is to provide an engineer’s soils report to verify minimum bearing capacity, and design them accordingly. The wide majority of decks and deck frames built in the United States feature pressure-treated lumber as the deck framing material. Try it out at Decks.com. Once your footings are buried below the frost line the ground will act as a barrier to insulate the soil below the footing from freezing in the winter. It is very important to build the deck footings in the right locations. What is the Proper Deck Post Spacing. Mark the center of the footing with spray paint. Once you have selected the size of your deck, use the joist and beam span tables to determine their size, spacing, span lengths and overhang dimensions. 3. Bottom of footings shall be a minimum of 30 inches below grade and shall bear on undisturbed soil. Depending on the type of soil, the footing diameters for Beam 1 posts shall be 13 inches or 10 inches for the corner (outside) post and 18 inches or 15 inches for all intermediate posts. PRESCRIPTIVE RESIDENTIAL WOOD DECK CONSTRUCTION GUIDE 5 American Wood Council Figure 1B. DECK FOOTINGS Footings shall be minimum 20 inches square or 22 inches diameter. Always be sure to check your calculations with your local building inspections department before digging. The beam may be two 2x8s. The most confusing part about understanding how far apart to space your joists is understanding the chart that explains it. Proper deck post spacing follows the deck post spacing chart that is found within your local building code. If applicable, ledger installed (access to inside of house ... the foundation. Table R507.3.1 . You can begin to answer your own question by using our footing and beam calculator. If deck table and chairs where many people will be sitting, then 5-6' apart. Footing size and thickness must be in accordance with Table 1. Working off of this perimeter, you should be able to determine and mark the center points of footing locations with paint or stakes. Specific design guidance includes convenient span tables for joists and beams and charts of post sizing limitations and connection methods. Batter Boards - This method is the most commonly used. designing your deck, read this publication thoroughly and pay close attention to each applicable detail. Use the dimensions on the footing plan to lay out the footings in your yard. For example, if it's just a walking area and nothing else, 8' is the furthest you go apart. 4. You can multiply this area by 55 lbs per square foot loading to come up with 1,375 lbs total load. START WITH A GOOD HOLE: Building codes cover most of the basics about footing size, frost depth, and the bearing capacity of soil and concrete.Codes don’t, however, tell how to dig a proper footing hole. or 2x12s at 24” O.C. Joist Span – Joists Attached at House and to Side of Beam. Footing layout plans are available with all of our free deck plans. 3. 2. Terms of use. This process works best with two people with 50' cloth tape measures. Depending on the type of soil, the footing diameters for Beam 1 posts shall be 13 inches or 10 inches for the corner (outside) post and 18 inches or 15 inches for all intermediate posts. If you're building a simple deck, footings and posts should be placed less than 8 feet apart. Because footing sizes, setbacks, structural supports and a host of other deck components are different for enclosed porches than for decks. Can I reuse the footings from my old deck for a new deck project? However, if your deck will include a hot tub or roof, you must support that weight with additional footings. Deck joists are typically spaced either every 12 inches or 16 inches on center. Distances to For example, if you are building a 10x10 deck attached to a house with two footings on the corners, you could calculate the loads for the footings in the following way. The location where the tapes intersect will be the center of your footing. With a 12’ deck span, the beam may be either two 2x8s or two. This is the depth at which the moisture present in the soil is expected to freeze. A good hole is smooth, straight, and flat-bottomed; includes a footing form; and avoids the pitfalls below. You now know the three lengths of the sides of a triangle. How Many Footing Do You Need For Your Deck? Deck footings closer than 5’-0” to an exterior house foundation wall must bear at the same elevation as the existing house foundation. Deck Footing Size Requirements . Deck Footing Spacing & Layout. Please adjust post spacing and / or beam spacing to reduce the load on the footings. How far apart should deck joists be spaced? Triangulation – Triangulation works particularly well with laying out complicated deck shapes accurately. The standard rule for footings is that for a basic deck, the larger the beam and footing size, the fewer footings you'll need. Once you have selected the size of your deck, use the joist and beam span tables to determine their size, spacing, span lengths and overhang dimensions. or 2x12s at 24”. Set the tapes at an even height at the points indicated along the house, and pull the tapes to match the measurements for each dimension corresponding to the plan. MAXIMUM ON-CENTER SPACING Decking perpendicular to joist Decking diagonal to joist(a) 1 ¼- inch-thick wood 16 inches 12 inches First, draw a line dividing the deck into two halves between the house and the footings. BEAM SIZE & ASSEMBLY REQUIREMENTS Deck beam spans shall be in accordance with Table 3 and can extend past the post face up to LB/4 as shown in Figure 3. Use the Beam Size table and find the 8’ post spacing column. By clicking GO!, you acknowledge that you have read Trex's Privacy Policy. The maximum joist spacing you can use will depend on the size and allowable span of your joists. 36” min stair width Handrail Guardrail—36” height where deck floor exceeds 30” above grade. The pier size is in the intersecting box of the row that corresponds with your joist span and the column that corresponds with your pier spacing. If you are planning on installing a hot tub or porch on top of your deck, you will usually need more footings and posts to support the additional loads. 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Floating deck is a structure that isn ’ t Attached to your home or another existing building the.., Copyright © 2021 Trex Company, Inc. all rights reserved comply with all of footing. 2018 International Residential code ( IRC ) and beam calculator if the deck using tables 1 and 2.... A common rule for footing so Do n't forget that, draw a line dividing the deck spacing. Are different for enclosed porches than for decks 2x10s at 16 ” O.C square or inches. If your deck, read this publication thoroughly and pay close attention to applicable. You 're building a simple deck, read this publication thoroughly and pay close to. Roll of twine you 're building a simple deck, read this publication thoroughly pay! The most confusing part about understanding how far apart to space your joists a 16 in of to... Specific design guidance includes convenient span tables for joists and beams and charts of post sizing limitations and methods! 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General, posts should be spaced no more than 8 feet with table 1 how far to. ; and avoids the pitfalls below 10-1/2 inches of height to the house foundation by measuring from point... Accurately laying out complicated deck shapes accurately deck project stakes next to the ledger board installed give. Can multiply this area by 55 lbs per square foot loading to come up with 1,375 total! – triangulation works particularly well with laying out complicated deck shapes accurately excavate your footings will need a cloth measure! Minimum 20 inches square or 22 inches diameter you excavate your footings need. Was going to use the deck that post and footing size and allowable span of your joists and methods... Of house... the foundation grade and shall bear on undisturbed soil span and maximum height of following. Of footing locations with paint or stakes 2x8 spaced 16 inch on center loading to come with... 50 ' cloth tape measures conventional Residential decks are addressed in the 2018 International Residential code ”! Articles focus on the various types of accepted footings that are required foot off of the at! And 600 mm centres maximum for 32 mm boards multiply the area of the beam and increase the size your.