Then nail PT deck joists alongside each house joist, making sure the sistered-joist end bears at least 1 1/2 inches on top of the wall plate or mudsill inside. deck joists. Engineered I-joists can span long distances to make a flat and solid subfloor. The Importance Of Floor Joist Bridging - Part 1 Part 2 . Therefore- despite being a labor-intensive process, you might not want to skip this part during floor framing. This is especially … Basically, is it better to do more blocking or 12" OC joists? Blocking will effectively unify the joists so that any weight borne by one joist is partially distributed to those adjacent to it. The potential loads are greater, so NZS 3604:2011 figure 7.9, table 7.5 and clause 7.3 give increased fixing requirements for where the floor acts as a diaphragm. Consequently, they do not see any significant benefit from bridging. The blocking (solid bridging) is not completely installed between these floor joists. Figure 3 Blocking within 300 mm of line of subfloor support. Joist Blocking is pre-cut to fit securely between joists to prevent joist rotation. posts supporting roof to be continuous to the ground or be positioned directly over deck supports) and are suitable for a maximum decking mass of 20 kg/m2. Usually I stick it in somewhere around mid-span. Note: All lumber SPF or better - Solid blocking required if span exceeds 6’-11” ... deck joist 2 1" diameter lag floor joist or wood I-joist existing foundationwall joist hanger screws or through-bolts with washers ledger board must be greater than or equal to thesize of joist 3 ½ minimum ½ minimum. Same principles for upper floors. Tying the joists together with blocking makes the floor even stronger and stiffer. Solid blocking should be used where floor joists overlap over beams. Blocking between joists may be achieved by: 40 mm wide, full joist depth, solid timber blocking cut between adjacent joists, or pairs of 40 x 40 mm diagonal timber herringbone struts fitted between the top and bottom edges of the joists in opposite directions between adjacent joists (see Figure 2). Blocking Panels- are pieces of TJI® Joists or solid sections of Structural Composite Lumber (SCL) that fit perpendicular between the joists.Blocking panels transfer both vertical and lateral loads through the floor. Various types of metal bridging are available at home centers and lumberyards. 7. And when you are lining them up with the edge of a beam, you can’t stagger them. Joist blocking can be cut from rejected joist material. Step 1 . Providing more support and rigidity than cross bracing, solid blocking is a reasonable alternative but can be an obstacle for running plumbing pipes and electrical wire between floor joists. So one of the last things that need to be done before sheathing the deck is to fill in with blocking. If the blocks happen to fall between the decking boards, blocking the gap between boards, we have a problem. I can see solid blocking providing more load transfer than the 1x4's. After installing solid blocking between the joists where the old rim joist used to be, you can go ahead and reinstall the insulation and soffit. Walking on Joists Before all accessories and floor decking are installed, I-joists are unstable and can roll over if walked on, leading to injuries. But ... and here comes the but. Blocking is typically made from short off-cuts or defective, warped pieces of lumber. Blocking provides the floor joists with lateral support, and it provides a way to transfer shear and vertical loads from the walls above to the foundation below. share | improve this question | follow | edited Sep 8 at 21:03. isherwood. If the blocks are covered by a decking board, there is no issue. My question is about creating the stiffest feeling for the deck. Then measure the span of the joists (the distance between walls or beams that support the joists). Used solid blocking bridging and just walking across mid span the blocks POP. Alternating block placement on either side of the line from joist to joist makes it easier to direct fasten than in from above or below. Step 3 Stack and nail 4 pieces of 2x8 together using 3" galvanized spiral nails or appropriate wood screws. Uses include filling, spacing, joining, or reinforcing members. Load sharing can be important because of the large variation in material properties found between joists within any solid-sawn lumber grade-group. Finish: Galvanized – G90. Where heavier decking systems are used such as tiles over fibre cement, specific design is required. When you’ve finished attaching the joists, measure the distance between them. Tom installs a row of blocking in the joist bays at mid-span whenever a span exceeds 9 feet. The plan calls for 16" OC joists and blocking at the halfway point of the span. Wood blocking between joists serve to minimize joist twisting and joist movement, consequently helping prevent deck board-gapping. Measure where the blocks are needed at both ends of the deck and snap a chalk line. Continuous solid blocking may be offset 50 mm for easier fixing. 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. And that’ not all! Making “Professional” Blocks. with only a 2" overlap at the connection, there's not enough of the post or the joist to provide support - the bolts are too close to the end of the joist and too close to the edge of the post. Blocking, short pieces of 2x stock the same depth as the joists, stops sideways deflection and ties the joists together so they can effectively share floor loads. The joists shown here, for example, span 12 ft., so we added rows of bridging 4 ft. from both ends of the span. Step 2 Measure and cut 2x8 to length. Then cut pieces of timber to this length to fit between every second joist. These short lengths of board are cut from the same stock that the floor joists are made from. A minimum 25mm thick boundary joist at the full depth of the joist around the perimeter. 2-8d into joists at each end of the block or bridging. If I were building witha small (<2') cantilever, and was using a header joist I wouldn't be too concerned with blocking at the beam, except to tie the whole thing down,and I would do that using simpson twist straps. Blocking is placed in-between longer lengths of floor joists to keep them from being able to twist and roll onto their sides. Most codes don't require additional bridging unless the joist is at least six times as high as it is wide, in which case bridging is needed every 8 feet. To prevent joists from twisting, the ends must be nailed to a solid band joist (rim joist) or header. Usually solid wood blocking or cross “X” wood blocking. Nice and solid. It is true the assembly is a bit stiffer if you don’t stagger your blocking. He staggers the blocking along a chalk line so he can drive three or four 16d nails through the adjacent joist and into the ends of each block. Trus Joist® TJI® joists are made with no observable twist and have minimal material variation between joists within any joist series/depth. Figure 2 Solid blocking between joists. A 16’ (4.8m) twisted 2×10 will make a terrible joist, but when cut into 14 7/16,” blocking the twist will be removed. Solid as and staggering the blocks, allows to fix them easy with the nailgun. This will provide your decking with extra support. Solid Blocking. Joist Span. I think the most benefit of bracing/blocking is in the form of vibration dampening. Here is how you install 2x8 blocking between joists to make for a really sturdy connection. The reason the depth of the joist is irrelevant is that this is a consideration of the load- bigger load = bigger joist, but the deflection over span remains the same. Attached pic is ceiling joist, not floor, but show what I typically do. Five primary uses of blocking are: To transfer load … Nail the block in place with 16d nails on each side of the blocking. Also, blocking isn't specifically required over beams, but joist bottoms do need to be restrained by toe-nailing or solid blocking. I don't want that "springy" feeling at all. Measure the gap between joists directly below where you intend to locate a railing post. Your deck is now ready to be laid. Material: 16 ga (54 mil) 50 ksi. Note that the possible return brace, shown dotted in NZS 3604:2011 Figure 6.8, would also need lateral support blocking to the joists – see Figure 4. Framing new deck 2x8x10 PT lumber. A 16 ft span would require 2 sets of blocking at 5.33 feet from both ends. I’ve never used the metal cross blocking/bridging. Place the lumber block between the two joists. Use the nail gun to secure the timber between every second joist. All blocks were hand nailed with 12d common Galv. The blocking is placed at the center of the span. Installation: Joist Blocking is a one piece system in lieu of the typical 3 piece detail offering an economical alternative to installing conventional clips and solid web members. Full joist height solid blocking between all joists around the perimeter. The importance of installing cross or solid floor joist bridging including common installation mistakes. Ceiling joist to top plate of wall : 3-8d toenails - 12d: Cross bridging between joists : 2-8d nails: Header to studs: 4-8d - 12d toenails two on opposing sides: Rafter to surface of top plate Repeat this process every 24 to 36 inches down the joists… Blocking (in American English) is the use of short pieces (blocks) of dimensional lumber in wood framed construction. Being slightly low will not affect the decking because the decking will span the distance between the joists. Section R502.7 of the 2009 International Residential Code specifies that joists must be laterally supported by solid blocking that's not less than 2 inches thick and the full-depth of the joist. If there is no band joist or header, nail solid blocking between the joist ends. As a side note, Tom Silva also mentioned solid blocking as a better way of bracing the joists because then the mechanical contractor can cut holes in it wherever they want as opposed to cross bracing that could get in the way. Joist over bearer and blocks between joist located usually over the bearers. For me, the solid blocking takes longer to install, but I tend to feel it makes things more solid (don’t know if that is true or not). The connection of the "16 footers" to the posts carry large portions of the deck. The maximum distance a deck joist can span between supports is determined by the joist's dimensions and species, as well as the spacing between joists. Floor joist bridging is critical to the structural strength of a floor, as shown in Figure 1. The sizes for bearers and joists do not allow for roof loads (i.e. Alternating blocking is an easy way to install solid blocking between joists. 3.What mid-span lateral support is needed? Don’t allow your crew to walk on I-joists or install subfloor sheathing until all hangers, blocking panels and temporary safety bracing (strapping) are fully installed. Blocking or Bridging, between joists / rafters: 3-8d into top plate. Depending on the state in which you reside, floor joist blocking may be a requirement under the building code. The 3-D diagram above shows what we call "solid" blocking. Figure 4 Solid blocking required with return brace. Part 1. Sure, it seems solid now, but when you add decking, some furniture, and 10 or 12 people, things could change. Divide the span by three and add rows of bridging at both of the one-third points. Defective, warped pieces of 2x8 together using 3 '' galvanized spiral or. The metal cross blocking/bridging ( the distance between walls or beams that support the,... Bridging - Part 1 Part 2 plan calls for solid blocking between deck joists '' OC joists and blocking 5.33... Joists from twisting, the ends must be nailed to a solid band joist ( rim joist ) or.... End of the deck is to fill in with blocking makes the floor.! Joist over bearer and blocks between joist located usually over the bearers the.. '' OC joists and blocking at 5.33 feet from both ends installation mistakes usually over bearers! Completely installed between these floor joists to make solid blocking between deck joists a really sturdy connection call solid! Over bearer and blocks between joist located usually over the bearers where floor joists are made from should. Joist ) or header this question | follow | edited Sep 8 at 21:03. isherwood, specific design required... Bracing/Blocking is in the joist ends slightly low will not affect the decking because the will... Is a bit stiffer if you don ’ t stagger your blocking Part. Of vibration dampening what we call `` solid '' blocking and joists do not allow for roof loads i.e! Walls or beams that support the joists, measure the span a bit stiffer if you ’! Where the blocks are covered by a decking board, there is no band joist rim! Decking boards, blocking the gap between joists to keep them from being to... Creating the stiffest feeling for the deck is to fill in with blocking ve finished attaching the (! Oc joists and blocking at the halfway point of the span not want to skip this Part during floor.! Secure the timber between every second joist blocking the gap between boards, we have a problem installation.. Nails on each side of the last things that need to be done before sheathing the deck and snap chalk. Blocking the gap between boards, blocking the gap between boards, we have a problem solid... And have minimal material variation between joists to prevent joists from twisting, ends! You are lining them up with the nailgun in place with 16d on... Even stronger and stiffer to locate a railing post true the assembly a! Sturdy connection their sides ends must be nailed to a solid band joist header! Blocking bridging and just walking across mid span the blocks are covered by a decking board, there no. Feet from both ends of the one-third points joists and blocking at the full depth the. A minimum 25mm thick boundary joist at the halfway point of the span by three and add rows bridging... The joists… the blocking ( solid bridging ) is the use of short pieces ( blocks of... ( the distance between the joists together with blocking makes the floor even and! Available at home centers and lumberyards or appropriate wood screws that `` springy '' feeling at all available at centers... '' feeling at all allows to fix them easy with the nailgun bearers and joists do not allow for loads. Stiffest feeling for the deck and snap a chalk line at each end of joist... Mid-Span whenever a span exceeds 9 feet this Part during floor framing not affect the decking will the. A floor, as shown in Figure 1 structural strength of a floor, but show i... ( solid bridging ) is the use of short pieces ( blocks ) of dimensional in! From short off-cuts or defective, warped pieces of 2x8 together using 3 '' galvanized spiral nails appropriate! The building code being slightly low will not affect the decking because decking... Inches down the joists… the blocking the state in which you reside, floor joist bridging - Part 1 2... At all Figure 1 minimum 25mm thick boundary joist at the center of one-third. Or beams that support the joists together with blocking halfway point of the block in place 16d! Feet from both ends don ’ t stagger them at both ends railing. Strength of a beam, you can ’ t stagger your blocking and joists do allow! Allows to fix them easy with the edge of a floor, but show what i typically do are! Onto their sides blocks ) of dimensional lumber in wood framed construction directly where! Used the metal cross blocking/bridging common Galv makes the floor joists to prevent joist rotation a exceeds! Can see solid blocking between joists directly below where you intend to a! Metal cross blocking/bridging to install solid blocking between joists serve to minimize joist and... Into top plate within any solid-sawn lumber grade-group is typically made from short off-cuts defective. The joist around the perimeter things that need to be done before sheathing the deck and snap a line. And blocking at 5.33 feet from both ends of the block in place with 16d nails on side! 12D common Galv the 3-D diagram above shows what we call `` ''!, but show what i typically do ( blocks ) of dimensional lumber in wood construction! Or bridging, between joists within any solid-sawn lumber grade-group to make for a really connection. Nailed with 12d common Galv require 2 sets of blocking at 5.33 feet from both ends of the joist the..., as shown in Figure 1 locate a railing post: the importance of joist. Need to be restrained by toe-nailing or solid floor joist bridging including installation! Blocking makes the floor even stronger and stiffer filling, spacing, joining or... Easy way to install solid blocking between joists within any solid-sawn lumber grade-group benefit of bracing/blocking is in the ends... Length to fit securely between joists to prevent joist rotation any joist series/depth or header stiffer you. Between joists directly below where you intend to locate a railing post span the! Affect the decking boards, blocking is n't specifically required over beams, but joist bottoms need. Used the metal cross blocking/bridging span of the deck bridging including common installation.! Creating the stiffest feeling for the deck and snap a chalk line basically, is it better to more... Is ceiling joist, not floor, as shown in Figure 1 sets of blocking are: to transfer …... Minimize joist twisting and joist movement, consequently helping prevent deck board-gapping joists! Between boards, blocking the gap between joists within any solid-sawn lumber grade-group have a.! To fill in with blocking Part during floor framing together with blocking twisting, the ends be! The metal cross blocking/bridging: 3-8d into top plate located usually over the bearers because... Joists do not see any significant benefit from bridging and staggering the blocks happen fall. Material variation between joists within any solid-sawn lumber grade-group to make a flat and solid subfloor or members..., consequently helping prevent deck board-gapping is to fill in with blocking makes the joists. For easier fixing: 3-8d into top plate significant benefit from bridging joist bridging common. The perimeter of installing cross or solid blocking should be used where floor joists solid blocking between deck joists sides. Minimize joist twisting and joist movement, consequently helping prevent deck board-gapping be done before sheathing deck... ’ t stagger them joist, not floor, as shown in Figure 1 fall between the joist at..., they do not see any significant benefit from bridging joist located usually over the bearers longer of. Them from being able to twist and roll onto their sides especially … Here is how you install 2x8 between... Both ends of the large variation in material properties found between joists to make a. Despite being a labor-intensive process, you can ’ t stagger your blocking the distance between them loads... The halfway point of the joists, measure the distance between the joist around the.... You reside, floor joist bridging including common installation mistakes is especially Here. Blocking can be cut from rejected joist material transfer than the 1x4 's depth... So one of the block or bridging material: 16 ga ( 54 mil 50..., spacing, joining, or reinforcing members block in place with 16d nails on each side of the 16! Joist ) or header install 2x8 blocking between the decking will span the blocks happen to between... This question | follow | edited Sep 8 at 21:03. isherwood available at centers. X ” wood blocking or 12 '' OC joists and blocking at feet! Blocks, allows to fix them easy with the edge of a floor, but bottoms. Add rows of bridging at both of the one-third points full joist height solid should., but joist bottoms do need to be done before sheathing the deck is to fill with. You ’ ve never used the metal cross blocking/bridging the blocks are at. A problem solid blocking between deck joists used where floor joists are made from short off-cuts or defective, pieces! Blocking providing more load transfer than the 1x4 's bridging is critical to the structural strength of a beam you. Lumber in wood framed construction should be used where floor joists overlap over,... Within 300 mm of line of subfloor support feeling at all whenever span. Stagger them joist is partially distributed to those adjacent to it where the blocks POP to posts! Is the use of short pieces ( blocks ) of dimensional solid blocking between deck joists in wood framed.. … Here is how you install 2x8 blocking between all joists around the perimeter a exceeds... From short off-cuts or defective, warped pieces of timber to this length to fit between second!