Standard green or brown coated screws are the cheapest. It all depends on your unique circumstances, but typically ½-inch diameter lag screws will get the job done. Carriage bolts feature a smooth, dome shaped head, without an external drive for appearance, safety and security. The gauge is the diameter of the screw. The SD screws are hex-head, and a driver comes with the screws. How to Install Stairs on a Deck with Lag Bolts. (see photo) [NOTE: The 2012 IRC – 2018 IRC all have the same table. Synopsis: In this article, Fine Homebuilding editorial adviser Mike Guertin details code-compliant methods of attaching deck-railing posts using FastenMaster bolts and screws combined with blocking made from framing lumber. To save you some trips back and forth to your nearest Home Depot, let’s break down what those numbers mean. A 3” length deck screws are preferable to 2.5” as they hold better. While the cost can be up to ten times the amount, it will still be peanuts compared to what you spend on your decking material. As decking products proliferate, it is important to understand that not every fastener works with any bracket or lumber. No Lag Bolts! You can't read too much into the code by making the inference that because a product has an ICC-ES report that a prescriptive table in the code book will apply directly to that product. Bolt Size For Deck Posts. All composite fasteners come with a weatherproof coating and a star or torx head. A reverse thread ensures the screw sits cleanly at level with the composite deck board. Usually, they are green or brown and come in a variety of lengths and gauges. Now your local inspector may give you a nod to use the IRC ledger attachment table to mount a ledger to a house with TimberStrand rim board, but that is solely at his discretion. For deck screws, you are likely looking at either 8 or 10 gauge screws. These screws are also coated but are narrower at #7 diameter. This creates a snug fit, which allows the teeth of the lag screw to dig into the walls of the pilot hole. Available in three lengths to accommodate your application. These systems are all designed to give the deck a clean look and are just as strong as traditional screws. Galvanized Simpson stringer brackets are designed to take Simpson SD #10 screws. Each pack of screws comes with a bit, which is star-shaped. Don't lag bolt a deck railing post to the outer band board that's nailed to the ends of the floor joists. x 9 ½ in. for those who like the flow-through design. Standard Galvanized Lags and Carriage Bolts: The most common method is to install ½” lag bolts with washers or carriage bolts with washers. Table R502.2.2.1 has three options: ½ in. Note: Modern recognized building standards require All support post to be at minimum a 6" x 6" notched post; with beam resting on post. For the heaviest connections on a deck, such as where ledgers attach to the house or to posts, use 1/2-inch bolts or lags. While these screws come in many designs, they are often ¼” diameter or more. Zinc-coated screws are the cheapest, and one of the most reliable, screws to use for pressure treated wood. Simpson Strong-Tie makes an excellent Deck-Drive DCU composite screw. The holes should be in the center of the post, 1 1/2 to 2 inches from the top and bottom of the framing. Just before leaving the AZEK booth, the AZEK team members wanted me to see an aluminum railing system they were displaying at the show. Choosing Structural Bolts Through Vs Lag Deck. They will have a corrosion-proof coating and are usually made with higher quality steel. bolt with the ledger spaced off the wall sheathing by ½ in. The head of the screw is star-shaped and comes with a driver. Finally, these screws are designed to fit within the holes of the brackets, as they are both Simpson brand. He is passionately interested in home improvement, renovation and woodworking. Bolts and screws must be located 2 in. Don’t assume that 16d nails are the same as ¼” screws because they aren’t. I plan on sandwiching the 6x6 post with two 12X4x16 redwood beams. Hundreds of articles and videos by top deck-building pros on how to design and build a beautiful, sturdy, and safe deck. As well, driving screws into brackets can be faster than nailing. You need lag screws that are long enough … Using Screws for Different Deck Materials, Screws are a whole different animal than nails. The only change is in the footnotes.]. First, pre-drill 5/16-inch holes through both the rim joist and ledger, then drill a ½-inch hole through the ledger alone. Easy Deck Inspection And Deck Repair Tips Family Handyman for proportions 1200 X 1200. This gives you something to hang your hat on when discussing your ledger attachment with the building official. Composite deck screws need material-specific screws. Remove the deck post and drill the deck post to the diameter of the lag bolt 3/8 inch is usually sufficient and drill the correct size lag bolt pilot hole in the rim joist. These numbers are important, and if you don’t know what you are looking for, you’re going to end up with the wrong screws. However, unlike a typical bolt, a lag bolt has a pointed end like a screw. Also, understand that screws and nails are different and have different numbers. The smaller diameter makes driving through the angled joist holder holes easier and lessens the event of joist ends splitting out during diagonal fastening. Where both sides of the joint are accessible, bolts offer the strongest … what size lag bolts for attaching beam to post in pergola construction I'm building a pergola and would like to know what size lag bolts I should use to attach the beams to the post. What diameter and length would be used? Regarding 1 1/4" TimberStrand - it is a product that is an alternative to dimensional lumber. x 1-3/4 in. Step 3 Screws used with composite decking typically have a much smaller head and tighter threads. In some cases, these screws have a reverse-thread just under the screw head. One interesting thing on pg 4 of the TJ literature, Weyerhaeuser lists a load rating of 475 lbs per 1/2 in. Within minutes I got into a tug-of-war discussion with a young AZEK employee after he showed me the cast flange at the bottom of the aluminum deck post. They hold well but are hard to drive and may split the wood. Are galvanized lag screws strong enough? What Size Screws to Use for Decking These bolts typically have a hexagonal head and are at least ¼” in diameter. Post Lag Attachment Hardware - These lag bolts are used for deck mounting posts into wood. The prescriptive fastener table is great when you’re mounting a conventional ledger to a conventionally framed house with screws or lags; but what do you do when you want to use proprietary structural screws like Simpson Strong Drive Screws or FastenMaster LedgerLoks, or when you have existing siding you don’t want to disturb? These bolts have an aggressive thread, a pointed tip just like a regular screw and a hexagonal head. i have been following an online guide and its good and i will try your idea. Therefore, 1 ½” length SD screws should be used for this connection. Composite screws, with their narrow thread, also have the benefit of not needing any pre-drilling. This is a good idea. You need a different type of screw for each part of your deck. This is a huge time saver. On many older decks the 4×4 posts were notched and then lagged to the rim joist with 3/8 in. Stainless screws, which are not coated, will not discolor cedar. When installing joist hangers, space is sometimes at a premium depending on your deck installation. If you have the money, splurge for stainless steel screws in pressure treated wood. Lag screws, also known as lag bolts, are screws that are frequently used for building with wood.They have extra-strength holding power that makes them more durable than other types of screws. Do your research and ask questions – don’t just rely on a product’s guarantee or warranty. These are also known as 14 gauge, but are usually labeled as ¼”. There are also smaller holes in the bracket through which regular screws would fit, but I think lag screws would be more secure. The 2009 IRC gives us a prescriptive bolting and lag screwing schedule to follow when mounting a deck ledger to a house. thanks, Sorry i forgot to mention the guide. smittyd said: 4 2x6's will be put around the bottom attached to the 4x4's. To properly attach a deck ledger using 1/2" lag screws, 5/16" holes need to be pre-drilled through the ledger and rim joist. If using standard, pressure treated deck boards as treads, then #8 3” coated deck screws is the best option. The prime focus of your deck, you want your deck boards to be secure and to look good. Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features. When installing cedar decking, stainless screws are a must. Treads are non-load bearing. If using structural wood screws, then you’ll likely be using ¼” diameter screws. Then other 2x6's will be put in as floor joist which will eventually hold the decking boards. A common rule of thumb is that a screw needs to go at least halfway into the wood beneath the piece you are attaching. For deck framing, structural wood screws such as Simpson SDS 1.5” screws work with joist and stringer hangers, as well as post/beam brackets. Figure 6 - Carriage bolt If you are using nuts and bolts, I would suggest the use of carriage bolts, as shown in Figure 6, as they provide finished aesthetics are much nicer than hex bolts. After that, a 1/2" hole should be drilled through the ledger only. However, the copper commonly found within today’s pressure treated wood will eventually eat away at the zinc. There are solutions and I’ll address them in future postings. Remember that a bucket of CAMO deck screws is about double the amount of regular deck fasteners, not to mention the cost of the jig. For cedar, stainless deck screws of the same diameter and length are best to avoid discoloration. Or use new specialty ledger screws, such as LedgerLOKs, which can be substituted for lags, simplifying installations with no loss of strength. Douglas Fir LVL – no attachment is allowed to strand lumber, SYP LVL, the mudsill, I-joists, floor trusses or other materials. Some building codes require a tension tie to be used in conjunction with a carriage bolt. Mixing and matching can result in corrosion and structural failure. Max gap between ledger and wall sheathing is ½ in – so no, you can’t use the ½ in. The best rated lag bolts product is the 1/4 in. Structural screws are thicker screws specially designed to be load-bearing. Of course, Weyerhaeuser only lists 'lag bolts' and not through bolts. House rim joist must be minimum of 2x sawn lumber or 1 in. For most of us, working within a strict budget, coated deck screws are the most viable option. The post bracket is embedded in the concrete pier, and there are 4 holes in the metal bracket for fastening lag screws to the post. These are brand-specific screws that work in tandem with a jig or bracket. To be specific, 8 gauge roughly equals a diameter of 4 mm. So I needed to find out what size screws to use for decking. You can use 4 x 4 posts up to a maximum length of 10 feet and 6 x 6 posts up to a maximum length of 18 feet. Aim to hold the drill bit straight and level as you work. Remember, if you are using cedar, then you should opt to use a hidden fastening system as these coated screws will stain your cedar. When you prepare a materials list for your deck project, throw a half-dozen extra galvanized lag bolts … This is pretty self-explanatory. The IRC no longer allows the use of dimensioned 4 x 4 or 6 x 6 lumber for the beams or girders that rest on the posts and provide the support for the joists. Re tighten bolts and lags after the first year and check periodically for tightness. After the gauge or diameter, the next number listed on a package of screws is the length. When you purchase screws of any kind, you are going to see a whole bunch of numbers on the packaging. bolt with spacer option over the siding unless it’s T 1-11. As well, the screws have a reverse-thread near the head. Stainless steel decking screws are ideal in any exterior application because they are extremely rust-resistant. Building codes define the minimum height and strength of the railing system, as well as the size of gaps in the railing – they must be small enough that a small child cannot slip through. Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers. I am looking at galvanized lag bolts (for the ledger) and carriage bolts (for attaching the beam to the post) for a deck. Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine. The use of a carriage bolt with a Simpson tension tie is ideal. or 1/2 in lag bolts or structural screws such as LedgerLoks. When the going gets tough, pull the bit out to … Lag bolts screws cost a third of the price of structural screws. Remove the deck post and drill the deck post to the diameter of the lag bolt 3/8 inch is usually sufficient … Using screws to affix brackets such as hurricane ties and joist hangers, you may need shorter screws that will not protrude through the ledger boards or joists. The bolts and lags must be hot dipped galvanized or stainless steel. Don’t … These are the most commonly used deck screw, the cheapest, and are effective. Installing railing posts depends on your local building code requirements. Many deck screws will not have the thread size listed, as the term “deck” usually indicates a coarser thread. I'd check with my local official before trying it. There are tons of different types of deck screws out there and it can be overwhelming when standing in the fastener aisle at Home Depot. That means that once you have the footings in place you need to install posts - which will support the beams - that in turn support the joists – that support the decking – and eventually you, your family and friends. Just don’t forget to read the fine print (AKA Footnotes) beneath the table and other code sections. Unlike other hidden systems that use brackets between the deck boards, the CAMO system relies on a handheld jig that fits over the width of a deck board. Now that we know the difference between the various screws available for your next deck project, let’s investigate the ideal size of screw to use for every application. Recommended for all types of wood or metal to wood construction where standard wood or deck screws or nails are too short or light. The important thing to remember when choosing a screw is to be consistent. As always, please feel free to comment below if you liked what you read or if you have a comment or question to share. Underneath the head is a square section that Use of a #9 diameter, 2 ½” long Simpson SD galvanized screws work best with the joist holders. in total. On either end, the jig has two angled holes that ensure the screw is fastened diagonally, out of sight. At the same time, lag screw pilot holes are definitely closer in size to those created for bolts. It is much stronger than a lag bolt simply because the railing post is fastened on both sides, whereas a lag bolt only attaches the post to one joist. For the most critical connections on a deck, such as where ledgers attach to the house or to railing posts, use 1/2-inch bolts or lag screws. Eugene has been a DIY enthusiast for most of his life and loves being creative while inspiring creativity in others. Not knowing the purpose of the notched 4x4's, weight bearing for the roof or railing posts, I would use the 1/2" lag bolts with washers under the heads. This is a 10x10 deck for a hot tub. Deck Post Danger. How much do lag bolts cost? 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