Steel track allows for the installation of fasteners as short as 20mm, but a staple fastener is essential for clamping structural elements to concrete. Anchor bolts are a staple fastener designed to resist lateral forces that could cause a building to lift or slide off the foundation. They can be divided into bent-bar anchors and headed anchor bolts, with the latter providing stability for the structure.
The best practices for anchor bolt placement include using an anchor bolt centered in every alternate stud cavity and stud spacing with a standard 16-inch on-center. Anchor bolts are useful for securing large and heavy objects to concrete, drywall, and other surfaces. However, they are not suitable for brick, stone, or block walls, so specialist masonry anchors are needed. Plastic wall plugs and masonry anchors can help achieve a secure fitting when fixing.
Anchor bolts are useful for securing large and heavy objects to concrete, drywall, and other surfaces. They are not required on walls below the stairwell, but powder actuated is fine for interior walls. Exterior walls are typically fastened to the foundation with J bolts or firing ramset or drilling wedge anchors.
Setting anchor bolts on the exterior is easy, either wet-setting or attaching them to forms. In California, a load bearing wall would need 1/2″ bolts about 10″ from the end of each separate board making up the mudsill and one every 4-6 inches. Concrete screws will work, but concrete screws should be considered for holding the wall in place.
📹 Why Abandon “J” & “L” Anchor Bolts in Wood Framing Construction FOR GOOD?
J & L anchor bolts have a long history in steel and wood construction. Some builders and framers still use them to this day.
Do interior walls require anchor bolts?
It is recommended that anchor bolts be spaced at least six feet on center and within 12 inches of each plate section’s ends when supported on a continuous foundation.
How to anchor an interior wall to a concrete floor?
Masonry screws are a simple method for fastening a wall to concrete, with a special bit needed to create a pilot hole. Drill at least 1/4 inch deeper into the concrete than the fastener’s embedment and remove dust with a shop vac. The hex-head style has an integral washer for a firm grip. Drop-in anchors, such as sleeve anchors, can be used to fasten a wall to concrete by tightening the hex nut. Lag shields are a more complex method, requiring drilling holes through the wood sole plate, marking the floor, drilling the floor, tapping the shield into place, replacing the sole plate, and driving lag screws with washers into the shields.
How to stabilize a freestanding wall?
The Studco® M110 StrongArm structural wall brace is a cost-effective solution for free-standing or isolated walls that require additional structural members to limit deflection and improve rigidity. This brace can be applied to standard steel stud walls, providing additional strength and minimizing lateral deflection. It can be installed without reworking the entire wall construction, as it is inserted into the track, fixed to the concrete, and bolted to the stud.
The brace is designed to be easy to install, requiring only a few steps, including building the wall frame first, inserting the brace into the track, fixing it to the concrete, and bolting it to the stud.
How do I know if I need wall anchors?
Drywall anchors are deep, designed to counteract the weight of items fastened to the wall. Before purchasing an anchor, use a stud finder to locate a stud, the sturdy pieces of wood used to frame the wall. If a stud is present, you can avoid installing a drywall anchor as it provides the necessary resistance. If a stud is not found, weigh the item to determine the best type of drywall anchor. Different types of drywall anchors are available depending on the weight of the item being hanged. Metal anchors are stronger and designed to hold heavier items than plastic ones. Drywall anchors are rated for weight capacity, based on the weight of the object they are used to hang.
Are wall anchors necessary?
Dwelling anchors are of paramount importance for the security of items affixed to walls, as their absence can result in the items falling off or causing the drywall to sag.
Do I need wall anchors for concrete?
When securing fasteners to concrete walls or other hard surfaces, anchors may be necessary. Different types of loads describe different types and directions of force on an object. When choosing concrete anchors, consider the load type and capacity, comparing it to the weight and potential movement of the object. Shear load, tensile load, static load, dynamic load, and impact load are all types of loads.
Concrete anchor types include concrete screws, hammer-set anchors, lag shields, lead screw anchors, plastic wall plugs, and anchor bolts. Masonry and concrete anchors are classified as light-duty, medium-duty, or heavy-duty based on their weight capacity.
Can you install anchor bolts after concrete is poured?
Anchor bolts are often placed after concrete is cast, but this is more common than expected. Drilling is necessary to create a void for the bolt, and hole depth and diameter must be specified to the installation crew. “Guessing” about bolt diameter and length is poor practice. Post-placed anchor bolts are inserted into the drilled hole and grouted tightly into place. A template is recommended for positioning drill holes and aligning bolts in the same holes.
Can you build a wall directly on concrete?
The statement is accurate when the wall is a low single-brick thick wall, 2 feet in height, comprising a 1/2 foot thick concrete slab on a well-drained base. Conversely, if the wall is a high wall, 8 feet in height, comprising three bricks and a 4 inch thick slab on a poor base, the statement is also accurate.
When to put anchor bolts in concrete?
Before installing a wedge anchor, ensure that the concrete has been set properly for at least 28 days. Avoid installing a wedge anchor in green concrete, as it can negatively affect holding values. The item being fastened also affects the choice of fastener due to its thickness and weight. When specified by an engineer, a specific type of fastener with a specific diameter and embedment depth must be used. If the wedge anchor is inserted through a hole in the item, the hole must be larger than the diameter of the anchor.
The surface of the item must have space for a nut and washer. The length of the wedge anchor is determined by the material being fastened and is manufactured with a minimum embedment and standard length.
What are the disadvantages of anchor bolts?
Mechanical anchors have main disadvantages due to their expansion types, which induce compression stresses in the base material. This necessitates sufficient base material around the anchor to withstand these stresses. When choosing fixings for applications, it is crucial to consider the pros and cons of chemical and mechanical anchors. Mechanical anchors can be categorized into two groups: expansion anchors and non-expansion anchors.
Expansion anchors, such as torque expanding anchors like throughbolts, shield anchors, and sleeve anchors, are expanded by being tightened, while non-expansion anchors, like undercut and self-tapping screw anchors, are expanded by the displacement of an expander plug. Mechanical anchors are essential for safety and can be used in various applications, but their use is often a significant decision for those with experience.
📹 Do NOT wet set anchor bolts – stated by structural engineers.
Anchorboltsetter.com Article from structural engineers against wet setting anchor bolts.
While the tone of this article may sound like I am against the use of J/L bolts period, there isn’t really much documented evidence I’ve found that shows failures in wood residential or commercial construction as a result of J/L bolts. J/L bolts are still technically allowed in the residential code and your building official may not have a problem with them either. The intent is to pass information about the issues other industries have had with them that I think might be a good idea to implement in residential construction. If you’ve attached walls to concrete using J/L bolts, it’s ok 🙂 I think J/L bolts have a place in very specific circumstances, however I do think there are much better options that are easier to utilize and do the job much better.
I’m also a licensed structural engineer specializing in residential and high end residential design. I don’t agree with the conclusion to substitute post-installed options for cast-in-place anchor bolts. While most contractors are going to love your article and always ask for a post-installed substitute, it’s not a one for one exchange. The capacity of post-installed options is substantially less than cast-in-place anchors. Not to mention that breakout is of equal concern and maybe even greater depending on construction practices and how the install went. Overall, substituting post-installed anchors for cast-in-place simply because they are easier to install for contractors is not enough to change industry standards. If your issue is with the breakout capacity being limited to the top of the J, then you can always substitute a straight bolt with a plate washer sandwiched between two nuts for substantially higher capacity. I think this article leads people astray.
I have used J bolts for 50 years. Never had any type of problems and I will continue to use them. Just because screw bolts are new doesn’t mean it’s better. Expansion bolts cause to much long term pressures on very fragile concrete. We pour all our foundations then insert the J bolts and will continue.
How ’bout you show us the threaded and epoxy anchors being pulled with your test jig like you did with the L bolt? I’m having a hard time believing the concrete wouldn’t break and blow out in the same way or that the bolts wouldn’t just pull out. I just want to see it. Everything looks good on paper.
Nice presentation and clear information, mate! However, I would avoid mechanical anchors, which induce increased stresses on a small section. I highly recommend the J & L bar as an engineer. But, as you said, it’s more convenient to use other types of anchors for site difficulties. Chemical bond anchors are a good alternative after concrete casting, but, the downside is that it’s expensive. A good engineer will sit down with his builder and discuss preferred construction methods and a budget, as some builders have more confidence to choose specific options.
Good article. We see L bolts in commercial all the time but they aren’t those little things your are showing. Not only are they bigger in all directions, they are usually paired with the horizontal rebar, the “L” hooks under the horizontal. In residential, IF you have enough wind to pull out a series of L bolts, you likely have much more important things to worry about. As an PE, you likely know the cause of failure is rarely one thing, the system failed not just one thing. For the sleeve or wedge anchors, the only person that knows if they “grabbed” or not is the person who installed it unless an inspector is going to walk around with a torque wrench. Epoxy is good IF the installer, usually the unskilled crackhead cleans out the hole correctly. I never messed with screw in anchor bolts Engineers need to stop trying to reinvent the wheel and just make a proven practice better. Make the horizontal part bigger and/or tile them to a horizontal and call it a day. 30 years as a commercial CM.
You generally don’t want to use wedge anchors on a foundation stem wall (which is most of the time). The distance from the centre of the bolt to the edge of the concrete is too short to comply with the manufacturer’s minimum requirements. You can even potentially blow out the concrete. The wedges push out and if the concrete is too thin, it will blow out. The close edge distance also substantially reduces the capacity of the bolt.
I believe that this movie was created as a promo for the post-installed anchor industry. The code requires CIP anchors to be emended 7″ min. which means that overall length of the anchor must be more or less 11″. Can you imagine how much the 5/8″ diam. KB-TZ2 SS (they do not fabricate HDG stock) anchor of this size is going to cost? It is a major impact on the construction cost. Good luck! So, CIP anchors are here to stay. In addition to what I have said above consider the following: 1. To install post-installed anchors into the sill plate (review the ICC Report #4266, for example) you need to provide a continuous special inspection at the site which can only be performed by an authorized third party, special inspection agency. I can guarantee you that it will triple cost of installation compare to the CIP anchors. 2. Please also show correct anchors with standard 90 Deg. hooks, not what was shown at the beginning of the article. What you showed was a substandard anchor with a short tale. See ACI318 or CRSI manual for correct dimensions. Good luck from California, SE.
I used all-threads with a washer and nut at the bottom in combination with two horizontal rebars running along the top of the foundation wall. For anchor plates I used custom made PL 5x3x1/2 with a punched hole. This size works well with both a 2×6 and a 2×4 wall plate and spreads the load across the hole width of the lumber for increased capacity. I also doubled up the wall plate in the bay with the anchor to increase the bending capacity of the wall plate. This also gave me more area for attaching the sheathing, which makes for a better load transfer. The problem with cast-in anchors is that one has to know exactly what the framing will look like to place them correctly. My anchors were installed pre-pour and concrete placement did rotate some of the anchors but they were easily straightened with a piece of pipe once the concrete had gained strength. The anchor threads need to be protected during the concrete pour so as not to gum them up. I used short pieces of PVC pipe with a duct tape cover. I have more confidence in these anchors than in any commercial system. It was a lot of work but this was for my own house and I wasn’t going to cut any corners.
I recently replaced a section of rotted sill and rim board on a 50year old house and discovered the block wall foundation had zero anchor bolts. The house was resting on the foundation and had not budged at all. Most barns in my area are sitting on stone foundations with mudsills in various states of decay and have no mechanical tie to the stones. I live in new england where we do not have tornadoes or hurricanes but it seems like this issue of anchors bolts just gets beaten to death.
Those 2 post vehicle lifts come with 5/8 inch wedge anchors and need 4 inches minimum concrete thickness, recommended 6 inch thick. I used 12 inch x 3/4 j bolts thinking that had to be better than 5/8 wedge anchors. I sawcut the concrete out, dug down 3 feet, tied rebar, tied the j bolts under the rebar, vibrated the concrete. I was a little nervous about 5/8 wedge anchors holding up 10,000 pound vehicle lift.
In my experience . Ever notice the slot on a CMU unit . That is where an L is supposed to be hooked . Not too many masons take the time to do that . Most with just push one down and core fill with broken cull and slop mortar in the cell .. They all wiggle . On concrete .. Most will just push one down and wiggle it, most are out of plumb and require knocking straight which shocks the concrete, On the perimeters of monolithic slabs, Cracks the concrete and sometimes breaks off the concrete, The threaded anchors are fine . But they can shatter the perimeters as well when tightening thus rendering them useless.. In the field ” anywhere besides and edge ” . Epoxy has it’s attributes as well . Drill the hole, blow it out and squeeze in the epoxy ..Yet in my experience .. If the hole has the least little dust .. It can be pulled up with ease when tightening So they really need to be cleaned out with with a damp cleaning tool . I find it hard to believe a sleeve or expansion anchor is better than a L bolt . Drill the hole and pound them in . They can be pulled up and out when tightening . So are you saying an L bolt can pull out easier than a sleeve. Wedge It ?? .. In a perfect world .. The J bolt is supposed to be hooked under rebar.. But few put the effort into making sure they are hooked and few put the rebar in the running location . It’s always Blow and Go . In my experience I have worked on some ” Beauties ” When installing the mudsills . The carpenters would just use cut nails, case hardened, or a sinker .
I have to disagree with this article, you as a P.E. should design based on safety or structural integrity but do it in the most cost effective way you can. If you were just referring to a retrofit solution then okay drilling and epoxy or screws would be on the list. But just saying no is a dis-service to your clients. L bolts are not for uplift, they are mostly about lateral movement, the nuts are not even tight typically. Uplift resistance is supplied by HUD style connectors for both slab or raised floor and the HUDs are connected directly to the studs. Mud sills are not part of the load path on the raised floor diaphragm or a slab. Using drilled anchors after the fact is just expensive from a labor stand point. What I noticed is a larger supplier base for L bolts which means the deep pocket corporations can lobby out the use of a low margin product they can no longer protect with a patent. What you see now is an overly complex anchor system they have complete control over with the associated higher price. -MG
I do not agree with your comments. Do you know you can put a very long L bolt such as 12-18 inch or even more into the concrete. There are also bolt holder available which can be installed before concrete pouring. Therefore you can accurately install bolt and pour concrete over it. You can also tie it to the rebar if design properly. It is very hard to drill a hole in concrete as such depth. Please provide some comparisons for both methods under similar conditions. Without comparison, it is not persuasive.
My experience is that drilling is easier and way more accurate without having to hang out material in the sill plate. Post drilled threaded bolts are commonly used in pole barn construction, and are more than adequate to hold the structure to the foundation. Having said that, I use j-bolts per code then add extra drill ins so that I have an anchor every 32″.
I am a general contractor with 40 years in the field experience and if the anchor bolts are installed as they should be, by code, they are to be tie wired and hooked to the horizontal strand of rebar. The sleeve anchor and screws you show are a far less substantial means of anchoring a sill plate and instill a false sense of security in folks who haven’t a clue of construction codes and practices. Just my 2 cents.
The anchor bolt application shown is for lateral loads, not uplift. The wall assemblies shown will only resist uplift until the nails pull out of the stud. When engineers want to resist uplift, they use hold downs or similar. Shear walls are rated for lateral loads and anchor bolts contribute to lateral resistance.
why not just make the L longer, it looks about the bend is only like half inch the it goes up like 6 to 8 inches….why not make the L shape like 2 or 3 inches long…. or make the anchor a T shape that is 2 to 3 inches each side or even say a + that is 2 to 3 inches north, south, east, west and the same length…..just asking…..
Nice article. But, I’m not sure if I agree completely. Firstly, it is not difficult to install J/L bolts. Those in the trade have been doing it for litteraly decades w/o issues. Secondly, where is the proof (aka testing article) showing J/L bolts failing due to uplift forces? And, thirdly, I deal with structural engineers all the time and most (if not all) of the specifications for AB have been the typical J/L bolts. Of course, using the screw-in bolts, and the expansion bolts are also good choices if the concrete is already poured. Otherwise, I don’t see why a structural engineer would phase these out when they are perfectly fine and gets the job done 100% of the time (provided its new poured concrete). Thanks.
Text at 1:51 states: “J/L bolt failures have been linked to bolts slipping off the concrete along the vertical shaft.” I don’t know what your source is for this assertion, but it does not withstand theoretical scrutiny. First off, the bolt shown has clearly not failed; it is the concrete that has failed. Ideally, you actually want to allow axial movement of the bolt w.r.t. the concrete at all points along the bolt, except, of course, deep at the fender washer or “J” or “L” area. Remember, concrete is strong in compression and weak in tension. Also keep in mind that the anchor bolt (as with all elastic materials) there will be elongation resulting from the axial force. If the bolt is bonded to the concrete, as the bolt is loaded, part of the load will be transferred to the concrete. Near the surface, you want all of the tension to be borne by the steel bolt, and none by the concrete, lest we see the failure type shown at 1:29. This why tape or tubing for the upper portion of the bolt is sometimes specified to prevent bonding to the concrete.
You can install HILTI powder activated fasteners that are 12 TIMES STRONGER than “J or L” bolts. I used them on my 1925 Model T garage expansion to fit a modern pick-up on top of 7500 PSI concrete stem wall. We have tornados and 115 MPH straight winds in thunderstorms har’ en Tussa, Orka-Homer, so I BUILT FOR THEM! My house was built 100 years ago in April this year. It’s held-up to wind, tornados, 6.7 earthquakes, 17 inches of rain in ONE HOUR and more. Do it RIGHT or do it AGAIN!!! The builders used a dozen iron cut nails between each stud into the concrete stem wall foundation thru the “shoe” or footing.
This was by far the best article I found on anchor bolts. My next step was going to be finding the ICR code regarding them. The article took care of both. I might get banned from the website, I plan to use L or J bolts for my project, lol. I don’t have a hammer drill so an L or J bolt would be the easiest and most cost effective in my case.
Hang on here. I learned how to do foundations from an old high school buddy in the trade. It was not covered in engineering school. Rebar is a big deal. The use of rebar I’d carefully documented. What I like to do and granted it’s tricky, is to slip the j bolt into the mud and then rotate it 90 degrees and slowly lift up. What happens is the bend is now under the length of #4 rebar. You can feel it catch as you fish around. Of course, one of the biggest problems is to put J bolts in the wrong place. Code dictates the placement schedule which sometimes interferes with the framing and sill plate. This is a pain. So the foundation drawing should show placement of these bolts. When needed, I will augment or repair as needed using a Titan bolt by Simpson.
Hey man just found your website, really interesting and very simple to understand. I’m sure you come across cantilevers in buildings, can you make a article showing a cantilever home, where part of a bedroom is cantilevered, and how one would attach a deck to the cantilever.. I see people shockingly attach their deck ledger board to the outside of the cantilever with no load bearing beam/post.. certain failure will follow with a heavy snow load or multiple people on the section of the deck attached to Cantilever.. definitely needs to be addressed!
Those expansion anchors are absolute JUNK ! I just built a garage where the concrete guys forgot a couple of the J-bolts and installed 4 of those expansion bolts where needed. Well, along comes me, the builder to install the sill and EVERY one of those expansion bolts pulled out of the concrete when I tightened them. You know what didn’t pull out of the concrete ? you guessed it… the J-bolts. I will not be getting rid of J-bolts anytime soon !
Is this a joke? Never in my life seen a J Bolt fail. Everything you showed, seems to my mind to be inferior to the J bolt. I have use similar screws to tie down frames walls to basement floors which were non-structural in order to refinish the basement as living space. I would be very leery of taking this article as real, without backing it up with other information and a lot of it. Almost 100% of houses are tied down to the foundations with J bolts and you never see them flying off during a storm. I am wondering whether this article is a joke or a marketing ploy to promote the things that he is promoting..
I was a tool and die maker for over 40 years in some very heavy metal industry with heavy machinery anchored to concrete floors…i have seen a lot of red head anchor bolts pull out of floors….these anchors bolts were sometimes inch in dliameter in 8 inch concrete pads….seen them get jerked right out by heavy equipment, but never a j bolt of he same diameter…seen them shear but never pull out
I agree somewhat, but for a house the L bolts should have plenty of hold down. Also smooth shank vs threaded? Here in Australia its all post installed anchors except for stuff that is big. What I mean by big is say a radio tower you might use cast in bolts but weld them to the cage in some cases, but a tower is also side loaded which helps the L bolt. As you said chem set anchors are very strong but they basically have a 75mpa resin in a 20 to 35mpa base material so you’re still limited by the base material being concrete at say 20mpa. This means cast in bolts are the strongest, not L bolts but rather threaded rod. What I do is if I have a square steel plate I need to anchor if I can set it in before the pour just make a plate in the steel and one out to align the bolts and now one bolt is achored with a plate and 4 other bolts.
If you’re a contractor and work in the field, J and L volts are essential. They’re for more than just what you’re saying. Bricklayers use a form of J and L bolts when tying brick into the side of the house. This is the difference between actually doing the job and thinking about doing the job. I was a construction steamfitting and electric for years. I saw the “plans” of engineers and designers. Most of the time, I saw what they said and laughed. For example, an engineer once had an outlet in the middle of where a double door was supposed to be. Now, I’m no engineer, but I think having an outlet in the middle of a double door is unnecessary and potentially deadly. I chose to ignore the plans and did not put an outlet in the middle of a double door. (We’re talking 3 foot from there floor. Another time I had an engineer try to tell me that a 351 Cleveland and a 351 Modified Windsor didn’t use the same engine block. I’m no expert, but I think the only difference is how the timing worked in the engines. I could also be wrong but I believe the only 351 engine block that was distant is the Windsor model. They didn’t recess turn timing chain. Other than that, as far as the blocks, they’re per much the same. But, I’m no engineer, so I could be wrong. I’m 52 years old. I’ve seen “new” ideas come and go. I understand it’s to “secure” Society, but it also creates an undue burden. First, J and L bolts are easier to put in when they concrete is wet, and if you know what your doing you can get a whole city block done in a day.
j bolts dont have to be installed that accurately… maybe if ur walls are 2x4s lol. you just line up your sill plate next to the bolts and use a marking jig or balance it on top of the bolts and hit it with a hammer. one big problem with post install ones that you missed, is corrosion. the only thing keeping those things in is thin pieces of metal. where as that j bolt can corrode a lot and still be strong. also with the wedge ones, they often don’t work as intented. more often than not, the wedge wont expand and they will seem tight, but will be completely loose.
I’ve been building medium and high end houses for 30 years and do my own foundation work. I’ve never even remotely had a problem with “j”. Bolts even in Alaska’s seismic conditions. I used 12×5/8 bolts 4 ft. O.C. As far as proper placement use a reusable plastic support that allows proper height and edge distance and you can float under them too.
None of these things resist uplift unless there is an accompanying strap that ties into preferably a large post built into the wall which is also rigidly strapped to the roof or beam which rafters or trusses are then strapped to. I’m not even a structural engineer and I know that much. Uplift forces are resisted by hurricane straps which distribute the enormous overturning forces across dozens of nails in shear. They are usually, if installed correctly, integrated with rebar to distribute the forces throughout the foundation. These anchors are primarily meant to counteract sheer forces and keep the house in place on the foundation. Not to prevent it from lifting up, because honestly, if you don’t have hurricane straps, the only thing keeping your house bolted to the floor is the 1.5 inches of 4 or 6 o.c. spaced nails along the bottom of your outer shear, whether OSB, ply, or that nifty zip stuff. Come on, man. Even I know this stuff.
On the Japanese article, they also use the L bolt, and also as a way to hold parts of the sill down temporarily while straightening the rest of that sill to the chalk line. So, it’s not useless to precision nerds. Maybe I could add a few screw or wedge anchors on the 4 corners of the sills after if it pleases you.
Hooray for you! Retired structural engineer. Never used a J bolt in my career but then again, I designed industrial structures. Anchor bolts were an issue from the start of my career until I retired 6 years ago. Mostly used threaded rod with nut on the end. You know the ACI has done a lot of research on this issue with pullout cone analysis, etc. J bolts are horrible. Kudos to you for highlighting this issue!!
………..I feel as though ignorance is a pandemic . I do Residencial framing for a living out in ut in the Rocky Mountains. 5/8″ “J” bolts hooked on the top course of rebar is not just the standard of the industry but is the Gold Standard. It is also the easiest of systems to install for a framer cuz wouldn’t you know it, but drilling 1 1/2″ of wood in your sill plate to accommodate a 5/8″ “J” bolt is much faster then drilling 8″ of concreat to accommodate a 5/8″ Titan screw. It’s not that any of these systems are bad, they are the best system depending on your application/circumstances. Try working in the fiend with these products for a hot minute. It will give you the actual context for applying your engineering degree.
Common sense would dictate installing “J” bolts before pouring concrete, and using the proper installation and of length bolt would be best. Install with j under rebar. When you talk about failure are you talking about design limits? Tensile strength? Proper spacing using the correct number of bolts for design loads.
Are you kidding? You should use exactly what the architect and/or engineer specifies. And your test??? Are you kidding about that also? For testing…You should use a deep enough anchor so the anchor itself breaks…NOT the concrete.. THen you know what it will really hold. We have put 1″ threaded rod down 36 inches into a footing with 4 inch plate washers at the bottom… What is that good for????30 tons of uplift? Sure,..I’m sure I’m just a fluke and haven’t read any plans (that I am involved with) where they do not specify J bolts…or fairly long allthreads with washers. If you look up on the simpson website,..you can see EXACTLY how much a 1/2 inch J bold embedded 9 inches (underneath the top rebar) will hold. Nice click bait,..that’s all I can say. I have never seen a post installed anchor allowed on a bearing wall.. And it will never happen on any job I am on. Post installed anchors happen,..and they are usually allthread embedded into concrete using structural epoxy,..and they have roughly the same strength as cast in place j bolt anchors…if they are the same length.
In California all post-set anchor bolts require deputy inspector, so Ive only used when there is screw up and bolt is missing or misplaced. Also J/L Bolts are not used as for holddowns in shear wall . just to keep bottom plate from kicking out and against minimal uplift /shear forces. Much longer curved / S shaped and inward angled bolts used for holddowns, SSTB16’s ect…never j bolts. Also always use Simpson strongtie anchor mate holders make setting all bolts pre-pour easier.
So for some reason we were required to put a particular depth of j-bolts. So it doesn’t do anything? It seems like post applied bolts like Titen are superior and mean the bolts are more properly placed in the end. Actually engineers in our area, typically specify J-bolts. Just haven’t changed their details.
1:29 your example shows it into the weakest part of precast concrete beam. That’s disingenuous as compared to most j bolt installations. Sub-Contractors can hardly read plans and don’t plan properly when they frame. It’s not just their fault. The contractors and builders chose the cheapest labor for so long there are no craftsman. I fundamentally disagree with the more expensive post pour options. People should just learn to be better. Just because a more expensive option exists doesn’t mean it’s actually better or faster.
Shame on you! So much misrepresentation in this article! You falsified the ‘J/L Bolt Flaw’ article. In your article @1:24 that is NOT a J/L bolt failing!!! You stole that article from someone else! And it’s a wedge anchor failing! Here is the original article youtube.com/watch?v=LBe4okYOvyA You used that article to imply it was a J/L failure. If you’re using someone else’s article you should be crediting them. Not passing it off as your (false) test.
Im a stonemason, Ive been fixing brackets and anchors to concrete blocks and concrete slabs for 30 years. Boundry bottom plate anchors blow out more slabs than j bolts, that’s a fact, countering your claim J bolts are tricky to line up. Yes j bolts can be tricky to line up, but you need to prove which method provides more uplift resistance, and therefore safer for my family. I would challenge anyone to provide testing results that show a thread on a concrete screw works better under tension than a bolt set into a slab. You say there’s a move away from the bolt embedded method to screw bolts and I agree. But if 3/4 bolts aren’t sufficient, then for another dollar more ” use a bigger bolt” and build a safer home. The only advantage is it’s easier and requires no thought to drill and place your threaded rod and screw bolts flat against your studs, saving time, but it’s not stronger, it’s weaker. I have pulled out plenty out pins and screws but you have to grind off or snap off embedded bolts.
J and L bolts are FAR superior to screw, epoxy and expansion anchors. The logic in this article is some of the dumbest I’ve ever heard. But typical of Engineers with zero building experience. It should be common sense that cast in place anchors are stronger and easier (with proper prep), but over complication is commonplace among engineers these days. Also, I’ve been in the industry 30 years and I’ve never once come to the consensus that installing J or L bolts or drilling out sills is “hard”. It’s actually the very opposite.. please, if it ain’t broke don’t fix it.. perfect example here.
As a contractor of 20 years specializing in excavation and foundation retrofitting, I STRONGLY disagree. Do not let your contractor use post installed anchors unless a mistake was made. ONLY when a mistake is made should a post installed anchor be used. I don’t doubt that calculations on paper show post installed anchors being similarly as strong as cast in place, but those calculations certainly don’t take into consideration all of the factors, like horizontal rebar being embedded above J bolts, weakening of concrete with micro cracks from drilling holes, greater moisture intrusions, removal of galvanized material from post installed anchors, etc.
I liked your article, and I understand using it in plain concrete settings. However, recently I bought a house that is sitting on a cinder block wall foundation. The house is on a slope, and half of the house is sitting on concrete foundation ad the other half is sitting on cinder block walls.The cinder blocks are over 10 feet tall. I think it would be easy enough to put in j bolts inbetween the cinder block joints to fasten the sill plate, but since the top of open and exposed on the cinderblock, I am not sure what else I could do? I could try and fill in the block walls at specific points, but I think that would take a lot of concrete, and I am not sure if it would settle correctly. I am not sure if there is something else out there to use?
65 years in the trades = This subject, and this presentation, is in my case amusing. Not to dwell on that, let me point out the obvious. Contractors are aware of the choices. DIYers don’t often get involved with projects that require them. Engineers wet themselves when you get technical, hence my amusement. See below!
Sir, I have been building for 60 years, dyna bolts regulrly fail, scew in anchors great for hold down or temporary formwork fix to adjoining concrete, rag bolts have stood the test of time in low stress engineered situations. This sounds like more white board commission for DEI academics have now got hold of the construction industry. Start using Ramset concrete insert bolts where you can run a continuous line of deformed rebar through them that integrates with the cocrete and rebar design. Heavens help the construction industry with this level of wooly thinking, talk about engineering loadings what we have going on here are mutational loadings . Welcome to the harsh roadmap of reality! KPP nz
Gave up J bolts almost 20 years ago for sill plates and use Titan HD anchors. CA code legal for sill plates. SO much time saved. Stand the wall, drill straight through the bottom plate into the concrete (about 30 seconds with the right rotary hammer), blow out the dust and impact wrench in the Titan. No comparison in labor saved.
Imagine your contractor, chewing tobacco like “no sir, we not doin none of that J bolt bullshit, we’re gluing the bolts right in da hole. Yup, gluin your house to the ground, buddy! Fuk a tarnaydah!” And the whole time a structural engineer with a clip board is fervently nodding in approval. You’d think you’re being pranked
Nice article but i have to disagree with parts. I’ve used j bolts and “stab bolts”, S bolts ( you didn’t show any of these) are also very common. You say they are difficult to use, I have to disagree, if you can read a tape measure you should not have any difficulty drilling holes in your plate for HD bolts. As for epoxy bolt applications, they are great but you have to be careful that the installer does a good job cleaning the hole or the bolt will not hold. Bottom line, stab bolts are faster (there are plastic holders that are designed to nail to the forms to hold them in the exact place they need to be when pouring our foundation) and less expensive than epoxy, but epoxy is perfect for the HD bolts you missed when laying out your forms. Now about using Red Heads for your HDs ? I live in earth quake country and i’ve never seen them used for HD where code requires a HD.
There’s multiple problems involved here and most of it boils down to costs. Builders will always select the minimum accepted standard to save money and this extends to the use of low-skilled and unskilled labor. My building career started with industrial form carpentry where everything was checked before and during every concrete pour to ensure proper placement of everything in the concrete. Nothing out-of-spec was allowed to pass, and most of the design work was above minimum standards to be sure load specs were met fully. When I got into residential work and saw the anchor bolts used I knew immediately they weren’t good, nor was anything about the whole job. And some of the blame belongs to Engineers who are also seeking easier cheaper way to meet testing standards instead of seeking improvements of performance which goes beyond testing standards and aims instead for something better in all respects. When it comes to longevity and resistance to damage of a structure overkill is called for to do the job best. For instance the pull-out strength of expanding anchors as will be used isn’t taking into account that the anchor itself puts extra stress on the concrete leading to edge-breakout. Nor does it take into account poorly done concrete work. Lab testing needs to correlate to real-life usage and conditions instead of everything being ideal which is only achievable in testing labs. Civil Engineering is a race to the bottom, with recognition and career advancement being more based on doing something cheaper/ faster/ easier instead of being done better.
Just ran across your article…I have to disagree with your opinion about j-bolts,however. I am not an engineer, but with 50+ years experience, as a contractor and carpenter, I have come to believe that a j-bolt, properly set in fresh wet concrete (which I agree is difficult), or cast in place and tied to rebar ( the best method, I think) is the strongest. I have used all the methods you explain many times. Of course, after installation, there is no way to see how well the installation was done. But that applies to all these methods.
Mr. Garth, Your article is unprofessional to say the least. You should submit your thoughts and suggestions for peer review by a professional committee. If approved, only then the code and recommended practices can be changed. Otherwise, you are confusing the average contractor and consumer who do not have the proper education to judge your opinions.
The screw in are more expensive and more labor intensive. If the J/L anchor has horizontal rebar over the J loop or L horizontal leg they have much more pull out strength than a screw in. You need to include a table of the uplift strengths. As for difficulting I am curious who finds them hard… not the concrete workers. It is probably the sill installers.
The problem with the post installed anchors is there usually not allowed for installing green concrete which may be fine for some use cases but there’s a lot of people that get out there on very fresh concrete and frame. I would be more concerned about tapcon style anchors that were installed into green of concrete personally over the j bolts personally. I have worked extensively in the concrete and rough construction but I’m not a structural engineer so maybe I’m wrong here.
While I agree with most of what you said, it is not difficult at all to place anchor bolts correctly before pouring concrete. It is just people are lazy or unskilled. Skilled construction workers usually build a wood template. The setup the anchor bolts with nuts below and above the template to make sure the the anchor bolts are at the right distance and plumbed. Then the make sure the template is leveled correctly and everything falls in place. Construction workers know what to do. Just the management ask them for insane production speed, therefore forcing them to cut corners.
I can’t see how titans or wedge anchors are more structurally sound than something cast in place. First you have to hammer the concrete to drill the hole. I would assume this makes it weaker than intact concrete even if marginally. Then to pull out a j bolt it has to overcome friction and straighten out the bolt. This seems like it would take a lot more force than the small metal on a wedge anchor or very course thin threads. The epoxy may be equivalent because it’s effectively patching the conference around a bunch of threads. I know titans are getting more popular but I figured it had more to do with saving time. If you can put them wherever needed after the fact and even extra ones, it’s much better than what happens if your j bolt layout is off. I’m a plumber so this isn’t my expertise but I would think if you wanted an alternative to j bolts, get the ones with the s on the end. I bet they’re hell to pull out. Anyway I’d be curious to see the test results on all these products. Maybe we could go back to how we used to screw toilet flanges to concrete. Drill a hole, then with a punch pack the hole full of lead wool, then drive a wood screw in
Does anyone ever bother to check the mud-sill to foundation attachment after an earthquake, a hurricane, or a tornado? This is only easily observable for homes that have basements and crawl spaces, as the concrete slab foundation actually conceals the anchor bolts and hold-downs inside of the finished gypsum board walls.
Is pull out test on the j-bolt was ridiculously shallow and does not at all reflect real world application. In residential construction using the post cure mechanical anchors add significant expense and time. You can’t install those in green concrete safely. Most home builders don’t want too late to begin framing more than 2 days after the pour is done. I don’t think the use of j bolts going away anytime soon and his justification for the more expensive alternatives seems poorly reasoned
Post-installed anchors will never replace cast-in-place for general sill plate anchorage. First, they cost a fraction of the proprietary post-installed anchors. Second, the contractor will have to hire (pay) a Special Inspector to witness some or all of the anchor installations, and they will have to wait for the inspector to show up to install them. Until the codes and manufacturers allow post-installed anchors without special inspections, they will be cost and time prohibitive.
Aren’t J bolts and L bolts supposed to be used with rebar running horizontal along the rounded inside part, essentially holding it down, hence why they are shaped like that. Makes sense that it wont hold if you are using it in a way it wasn’t intended to be used, or I may be wrong, maybe somebody should do a “I was today years old when I found out….”
If you install the J bolt or L bolt correctly it would be stronger than the screws. The use of rebar with J OR L bolt makes then very strong. I have installed J bolt tied to rebar laying in the J. The rebar goes the length of the foundation. The only way that J comes out is with the complete foundation.
dude makes no sense, he had that bolt in inch of crete for his dumb jig, if instaling a hook into concrete is complicated for you then that’s not the industry for ya. Those expansion bolts will crack concrete and still not provide the strength nesesary, the screws with glue are useless come on bro, most of those epoxies are not even made for harsh climates…
You just earned a new subscriber son!!!🤙🏼 I’m a 35 year GC from South Florida where strong winds and Hurricanes are a big issue in my field. Inspectors are hard on us with matters such as the one on this article. And you’re absolutely right about these concrete anchors!! I appreciate your tips and I will definitely search through your other articles. Thanx man!!!🤜🏼🤛🏽 and keep up the good work!!!
in fl cbs uses rebar pored in the slab, but i like to see something like a 3-4 inch each side t even the alternatives are still straight shafts now i do know good engineering should have tests proving the claims by makers, i might like a combo of some j or l plus some drilled in if in hurricane or tornado areas although i would only build filled block or poured concrete in the tornado ally plus a shelter
You can just chill in a rebar on sideways on an angle like 20° or so fill it with some grout or some Hilti head epoxy put it in there and then well then that’s something on the end of it to hold your post down that’s just as strong as an anchor bolt going straight down relying on that little edge I think it’s even stronger it’s like alligator nailing
I’d recommend using epoxy with tapcons. I drilled the right size hole and used them but they free spin in the hole after tightening. It’s a basement wall non load bearing so I’m not worried about it. I put the studs in after the sill because I didn’t have room to work with so it’s really tight to the floor and doesn’t have any lateral movement. If I did it again though. I looked for the epoxy at Lowe’s made for anchors, none in stock. I don’t know if all epoxy is the same or not.
Guessing a plate with welded thread bolts is out of the question? Yes that means being installed before the concrete and to ensure the proper thread height is above but would be way stronger as the plate in the concrete would distribute the pressure of pull. Just an idea but yes a lot of drawbacks there can be.
my cousins husband worked for Napa and went to a trade show where they demonstrated using the epoxy –seems the epoxy Vapor extends out into the concrete expanding the area of adhesion.. other types of hold downs pulled out with little concrete damage the epoxy consistently pulled out a 4 to 6 in section of concrete!!!!
I’m a mechanical engineer, building my own home. I used L bolts as called out by the structural engineer, but upgraded to galvanized for a few extra bucks. In a few locations we needed additional bolts such as around doorways so we installed Titen bolts (screw anchors) in those locations. I loved using the Titan bolts and they were very easy to install. The concern I have is the design heavily relies on the integrity of the thread. It seems as if the thread would be the weak link over time as the thread corrodes and rusts. The thread is fairly thin so it feels as if it could decay relatively fast. I would suspect the galvanized layer is also somewhat compromised as the threads are twisted into the abrasive concrete. I wonder what kind of life span these bolts have been tested to.
There’s the structural design and there’s the builder. In the garage at my home growing up, we widened the garage and found one of the J bolts was just the top inch, there to fool the building inspector. It must have landed under a stud, so they cut it off, and drilled a hole next to the stud, put a washer and nut on, and dropped it into the hole they drilled.
Any anchor will do a great job holding the sill plate down no matter how much lifting force is applied to the structure. The problem is that every part of the structure that is not securely attached to each other with anything but nails can be pulled off of the sill plate. So the studs need some sort of fastener to tie it to the sill plate and top plate and the rafters need some sort of fastener to tie it to the top plates and the roof deck needs some sort of fastener to tie it to the rafters. Otherwise your entire house could be lifted off the foundation except for the sill plate.
Concrete dust, drilling concrete takes a LOT of time and creates a lot of concreted dust that (in my case) required an INSPECTOR-seriously- to watch the newly drilled concrete hole get blown out with air (which is typically not readily available on a new construction) or brushed with a bottle brush before applying the epoxy. Otherwise the concrete dust in the newly drilled holes do not allow proper adhesion. You simply can’t blow it out with a breath from your lungs (face full of concrete) or with water (puddling). Your theory is good, real world experience it is not practical. You should invent something better, you have great ideas.
Your understanding of the science is off. A correctly implemented cast in anchor will always out perform an anchor that is installed into a drilled hole. Drilling holes into concrete compromises it’s mechanical structure always. They have cast in anchors designs for every job. Any engineer worth his salt would know this.
A buddy of mine that is a builder is still using the J bolts even though he’s a mechanical engineer himself. I think it’s for the same reason he has lots of other issues on his jobs, when he tries to tell his subs to do something they tell him “you don’t need that” and just keep doing what they want. The other thing I see on his jobs is that they don’t install the bolts right away, it’s the last thing they do before leaving and the concrete is starting to get pretty stiff so it leaves a hole around the anchor from shoving it in. Then after all that half of them end up being in the wrong place when the framers get started. But when you always go for the cheapest guy you can get and all of his workers are illegals that don’t speak English much less know what a building code is I guess that’s what you get. I would think it would be worth it to use the other anchors simply because you can make sure they are where they need to be after the floor is framed.
back in the day in residential work when pump trucks either weren’t available, or the builder didn’t budget we would sometimes have to “loosen” it up to get it around to the back wall. we used to rip up the cardboard tie box to get the bolts to float overnight. after the framers put the sill on, they would mash over the bolt instead of using the nuts and washers to save time. I haven’t heard or seen any of those houses go anywhere. for that matter, houses built in the 1800’s are still on their stone foundations with no anchor bolts.
Well, after perusal, just a bit of your article, here, it’s unwatchable, for tradesmen, who been in the business for 50 years I must be just drooling into a cup. I have never ever ever had a foundation crack on me around an anchor bolt. I couldn’t even count the number of anchor bolts thousands I’ve never seen a failure never. i’m guessing it’s either poorly mixed concrete or your mixes to dry or they’re waiting too long for the wet set, your premises is complete nonsense it’s more about the mud and the skill of the worker.
Ive seen hundreds/thousands of wet-set bolts. Never seen any of the problems you’ve shown. Only way to see such problems is setting after concrete starts to set. One of the last bolts looked like a straight bolt dropped on a hole drilled afterwards. As for this system, way too many pieces. Grey color is a ridiculous choice for the locking piece – lose that in a heartbeat. Perhaps if there were a tether of some sort to prevent losing the pieces.
My contractor accomplishes the same thing with a piece of 1 by nailed to the form and the anchor bolt set at the correct height and distance from the side. It is fast, easy and accurate and the building inspectors do not have a problem with it. Wet setting is prone to error both in placement and orientation (height of bolt, distance from the edge, whether or not it is true)..
I design reinforcing systems for building slabs. I use at thread tube welded to the metal frame that accepts any threaded bolt or rod. The end of the tube is at floor level, and it aids the concrete contractor to level the floor to that point. They can even use a helicopter to level the floor, all the way to the edge.
I don’t know if the product is a contributor (advertiser) to the program/channel but, while I do agree he anchor bolts must not be set on wet concrete, the plasticky product is unnecessary and not the best tool. Just create a template with a plywood. Set the anchor bolts with washer and and nuts above and below the wood template. You can also tie the anchor bolts to the center of the rebar cage or horizontal rebar. When set this way is rigidly secured, and while pouring concrete a vibrator can be used so there are no air gap or honeycomb in the concrete.
Pre setting the anchor bolts prevents you from getting a good finish on the top of the wall. You’ll have air leakage pouring out of your building at each A-bolt location. We are taught to carefully place the bolts into the wet concrete but not to wiggle them up and down, rather tap the forms to consolidate the concrete around the bolt.
Agree that setting first looks better. different twist is 1:00 bolt is not set in center, too close to edge and what ive seen just in this article, crew is quite ignorant, may have even kicked it after install. Maybe we should use 2x6s instead of 2x4s or make foundation larger and stick out into dirt. Our Govt. and its great diversity / foreign competition / allowing more companies to leave America than any other country would ever do ( except maybe Rome or England ) in History has lowered us to near insanity already.
Real article starts at 1:46. It’s obvious people complaining about the pageant winner, or over emphasizing that they add anchor bolts prior to pour, have not watched the article past the time I shared above. However agree with the sentiment, terrible intro to showcase a unique (regardless of necessity) tool/product.
Sales pitch code allows wet setting, these guys should have used a real product not a 3d printed version. The blog link is gone so I bet they went under. I mean they are competing with a cut to width stick (metal or wood) with a hole in it. Run the steel through the hole push down line up edges and position is set and so is depth.