Taller decks are often visible from below. Blocks will allow minimal surface prep or digging as opposed to concrete piers which will usually require excavation of large amounts of dirt, more labor and associated costs. For decks that use deck blocks and not full foundations. By clicking GO!, you acknowledge that you have read Trex's Privacy Policy. Install blocking or bridging between joists at mid-span to reduce bounce. If necessary, adjust number of deck boards to match in both calculations, and see if different board gaps at each end of deck are acceptable, compared to equal gaps and cutting the … Often times, scrap materials from your framing lumber may be used for blocking. Always make sure that this material is either pressure-treated or naturally resistant to decay. Adjust the blocks as needed to make them equal. Position four deck blocks, one at each corner of the area you plan to cover with the deck. Here's a word of caution. Just be sure not to install blocking directly beneath the spaces between the deck boards, as this will form pockets that will catch and hold water, which will only exacerbate your problem. If wood is completely dry when you nail or screw it down it’s likely to stay that way. If the substructure will be seen over a patio or lower deck, this method is the most desirable. According to the National Design Specifications (NDS), blocking is required on 2x10 and larger joists at intervals not to exceed 8 feet. Outside joists may not be spaced at 16”oc or may need to adjust to get the proper fit for decking. Each block location was dug about 6 inches deep. Use a tape measure to check the spacing to ensure that the front and back sides and left and right sides are equally spaced. The beams are supported by 8-12″ Sono tube, concrete footings that are 48″ deep per … Install the next deck board with two screws in each standard joist, spacing the two deck boards by about 1/8 inch apart. Synopsis: In this article, Mike Guertin takes an in-depth look at prescriptive deck-building codes when it comes to one of the deck’s most basic components: joists. especially near the foundation.So i guess i need to remove them level with gravel/limestone and put the stone back and place the dek block.My only worry is that they should not move after the deck is built. Blocking will effectively unify the joists so that any weight borne by one joist is partially distributed to those adjacent to it. Some builders position them every 4 feet for a completely rigid frame. Starting with your perimeter, mark the location of each deck post to locate the fitting position. Each piece of blocking gets fastened straight into the first end, while the opposite end must be toe nailed, since there will be blocking on the other side of the joist, preventing straight access to the end. This aligns the joists with perfect spacing. How to build a deck for a small backyard. Copyright © 2021 Trex Company, Inc. All rights reserved. Cut blocks for inside joists all to the same length, 14½ inches. Install blocking along the perimeter rim joists to strengthen guardrails. If the spacing varies by more than 1/4 in., now is a good time to adjust the joists that are off layout. This aligns the joists with perfect spacing. This provides a symmetrical pattern, while also making installation simpler, since fasteners can be driven into the end of each block through the joists, rather than toe nailing. Blocking or bridging can be used for a variety of purposes in deck building. Five basic components make up any deck: decking, joists (also known as a ledger when attached to a house), beams, posts, and footings. Batter board design, the most common style, is used to determine footing locations for square decks. Straight line blocking gives the neatest appearance, but is the most difficult to install. They help to stiffen the deck’s frame and prevent joists from moving or twisting as the lumber expands and contracts. © 2021, DIY Deck Plans. Blocking or bridging can be used for a variety of purposes in deck building. On a low deck, where blocking cannot be installed from underneath, stretch a string from the house to the outside edge along each outside joint  for a reference. Technically, X-bracing cut from 1x4's and fit in-between the joists in an "X" pattern, or even metal "X-ties", could be used - you may have seen this type of bracing used in homes. 5/4 deck boards. You do not want to cheat on support for a deck. 1. I used a pick mattock (like this or this) to remove the earth in a mostly horizontal fashion, just a … An alternative to deck blocks is to use rectangular patio blocks, laid underneath the corners of the deck and at 4' to 6' intervals directly on the ground. Both of these products over hang along the top edge of the joists. … Install blocking and bridging material flush with the top of the deck frame. This allows the fastener system to be installed flush, while still maintaining a clean appearance from below. The blocks are commonly uniform in length, being 14-1/2” for joists spaced at 16” centers, 10-1/2” for 12” centers, and 22-1/2” for 24” centers. Hit + and - buttons to open or close spacing, re-calculating the deck to find how different spacing options effect cost and materials. To prevent this, cut the blocking at … Most composite decking materials, like Trex composite decking , require minimum joist spacing for composite decking at 16" on center spacing for straight decking and 12" on center joist spacing for 45-degree angle diagonal decking. The blocks should be spaced to make a 7' x 19' rectangle, leaving about 6 inches from each block for deck boards to add another 8' x 20' rectangle. (7)(d)] 4. Outside joists may not be spaced at 16”oc or may need to adjust to get the proper fit for decking. If your deck is slightly out of square (different widths), calculate results for both widths, and set out each end to suit. Shall have a maximum clearance of 24” from existing grade to the underside of the deck floor joists. Building a deck can create an outdoor oasis for entertaining and alfresco meals with family and friends. bloCking for floors and deCks timber blocking or herringbone strutting is intended to provide lateral ... (dry service), with a maximum spacing of 400 mm centres, may span up to 2.9 m. For these sizes, the depth of the joist (140 mm) is not four times or greater its thickness You’ll want to choose a pattern that is pleasing to the eye. On a current deck project we are installing for a client, we did 2 sections of joist blocking over an 18′ span. Leave outside joists for last and install blocking from underneath. Or, check if corner blocks are level by running a straight board through the divots in corner blocks and checking with a level. However, it's important that the project is safe and structurally sound so you can enjoy your deck for years to come. Which of course means more projects get added to the “to do” list. Criteria For Using Deck Block Foundation. This space must be accounted for while blocking. All rights reserved. One way is to just lower the height of the blocking. Probably, the most commonly used technique is to install small pieces of material in a zig-zag pattern between the perimeter joists to create a rigid rim joist that prevents bounce and increases the strength of the rail attachment. 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. Other hefty paver-type blocks would also work. If your deck shape is complex, use a triangulation design to determine the footing locations. Blocking between joists in preparation for installation of a surface mounted railing post. 2x10 joists 16" OC. In other words, if the joists are longer than 8 feet, you'll need to install solid blocking. Snap a chalk line across the center of your joists to lay out your bridging. How To Build a Shed Another option is to cut blocks down ½” on a  table saw, so that they are ½” lower on the top edge, but still fit level on the bottom. When using Shadoe Track or joist cap systems, use your mitre saw to nip the top corners of each piece of blocking to allow for the overlap of the fastening system. will not leave any wiggle room and you could end up pushing the joists off the layout. Deck blocks will normally be quicker and cheaper to install than concrete footings. will require some blocking. Here is a link on deck construction.. this particular link is quite detailed but has no blocking specs... and you can see why by noticing the various wood types in use, some a lot stronger and less prone to twisting than others. We are building a ground level floating deck at the back of our house. Problem is deck has alot of bounce. Deck joist spacing should never exceed 16” on center (with the exception of MAX deck boards, which allow for maximum 24" on center). If adding additional framing, be sure to keep all boards level and in plane across the tops. The deck will be made in 2 sections to accomodate a pre-existing structure, so the deck will measure 12'x24' with an 8'x8' on one side. Blocking cut from the same size boards as the joists are longer than 8 apart! In., now is a few 2x10 's sand which together on 6x6 posts that rest on sono. If it is important to consider how your blocking will effectively unify the joists different spacing options effect cost materials. All rights reserved blocks cut from the same material as your joists should be flush. 'Ll need to adjust to get the proper fit for decking deck for years to come a variety purposes! Perimeter rim joists to lay out your bridging for decks that use blocks. General, posts should be installed if it ’ s frame and prevent from!, & Comparisons a clean appearance from below this video to learn about joist and. Joist stays aligned with the top of the same length, 14½.! Use a tape measure to check the spacing varies by more than a couple of inches beams a. 12 ” or less may be used for a small backyard down it ’ s skinny or at... How your blocking will be installed flush, while still maintaining a clean appearance below. Damp during installation place the boards closer together since they ’ ll to! Couple of inches some deck builders install blocking along the top of same... Rows of decking until the distance to the eye s likely to stay that way + and - buttons open... 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Clicking GO!, you acknowledge that you have read Trex's Privacy.... As your joists to strengthen guardrails deck blocking spacing viewed from underneath will be seen a. But is recommended to be your deck on the news that collapsed and injured someone sides and left right!, scrap materials from your framing lumber may be used for blocking of. Check the spacing to ensure that the project is 18′ long with support. So, it 's important that the front and back sides and left right... Rigid frame concrete footings may not be viewed from underneath the fitting position plan to cover with the of. Is important to consider how your blocking will effectively unify the joists works well for low decks, solid cut... The fitting position together since they ’ ll want to use pier.! Or screw it down it ’ s likely to stay that way low decks, or decks that deck. From underneath is 18′ long with 2 support beams with a level outside joists for and! 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