Although I like notching, the shear strength of a grade 2 carriage bolt is 13,500 lbs and grade 5 is almost double at 24,400 lbs. The strength of the bolts is well in excess of the lumbers ability to hold an extreme load. The biggest danger is the lumber could split at the bolts when places under excessive loads.
15 years in the carpenters' union and this is the way we get taught to do this when we go through apprentice training. I have worked with staff from This Old House, including G..C. Tom Silva, and this is his method too.
@@lincolnhobartmiller What is wrong with that? It seems a bit unusual as carriage bolts have square just below the head so you'd need a big washer, but surely it's better than not having one even if it's not 100 needed?
After 30 years in business, in Tenn if you notch a post your asking to introduce water into the heart of the post which will then freeze and thaw and make the post split over time. Regardless of whatever type of "waterproofing" you add it let the post come apart faster then carriage bolts or lag bolts. I recently repainted a deck i built 25 years ago using lag bolts, stil good and sturdy and straight. I repaired a 10 year old deck another person built with notched posts that was already showing serious degradation to the posts. Decks were built for years and years without notching posts. Unless building codes demand it, dont do it.
Exactly! Just level it, screw it in place, then bolt it together. 1/2" carriage bolts are not going to fail. Water will get you every time, though, if you don't let it drain.
After showing this video to a structural engineer, & an architect, and speaking to friends and family who've built many decks in their years, I concluded that duct tape is the best choice.
1/2" bolt has ~7000 lbs of sheer strength x 2 = 14k lbs at each post in this 'wrong' example. The 6x6 post itself has about the same /compression/ strength. The real reason for the rabbit joint is wood shrinkage. Over time, the treated lumber will shrink and a bolt will loosen. With the beam directly supported by the meat of the post, loose bolts from shrinkage do not compromise the integrity, and can and SHOULD be checked to be tightened.
Bolted joints work by creating friction between the two surfaces, therefore if the bolts are tightened sufficiently all the shear load is taken by the wood. The “wrong way” is fine assuming the bolts never come loose. When they do (most likely by the wood shrinking/relaxing under the compression from the bolts) then the wood will shift and load the bolts in shear. The failure point will then likely become blowing the bolts out the top side of the beams. The “right way” is safety in the long run as it doent matter how tight the bolts are as long as they stop the beam falling off the post. Also, carriage bolts shouldn’t have washers, they have a square protruding under the head that’s intended to stop them spinning. The washer will reduce or prevent the protrusion engaging with the wood making it likely impossible to tighten fully.
@@gregoryclifft7398 gotta agree with u timber shrinks across the grain especially wet treated timber as it dries incorporating a shoulder in to the post for the beam to sit upon is definitely the way build heavy load bearing floors
Maybe speed is important if you make lots of structures, but for a DIY that does this a couple of times in a lifetime, what's a few extra minutes? I would like to know which one is better? Lag screws or carriage bolts? I would still choose carriage bolts because they "compress" the wood and add friction while the lag screws "pull" the wood to add friction.
Normally the bolts won't see much in shear due to the friction the bolts are providing between the two wood pieces. The problem occurs when the bolts loosen up and start taking the load directly. Even so, the typical homeowner's deck doesn't carry huge amounts of weight (except maybe when piled with snow) and one carriage bolt in a deck would never be a single point of failure. That being said, best to build to code.
I've been a carpenter for 48yrs. All the comments here about the strength of carriage bolts is correct. Unfortunately this guy stressed (pardon the pun) the wrong point, namely that too much load here, and it would be the beam that would give out first. It would split around the load point on the bolt.
yep, I once built a small water tank stand and greatly understimated the load. It was built in this style with large screws suitable for treated pine. Failed around the screws with wood splitting exactly as you describe. Seeing it was all in place i used some heavy duty supports brackets (angle iron) and thru bolts. Been sitting there for 8 years now and still seems happy. Lesson learnt.
I think your comment is the most informative here. It explains the reasoning behind the video's message better than the video lol. I wonder if there is a way to get drainage/airflow with a system like this to prevent long term rot between the 3 peices of lumber?
What he is showing is how they used to attach the beams on decks. If you have been a carpenter for 48 years you already know that. They never notched the post back then and even in the 80's.
DUUUDE! So glad to see you here. I've been a fan for years of Decks, Docks, & Gazebos. You're quite a crafty guy & seem to really enjoy what you're doing, especially the making people happy part. I'm not keen on notching posts but I see your point. I hope you're still around, making things happen.
Oh Mark you said it perfectly, alas, from all the posts, you need to go off on a 15 paragraph tangent, then they'll listen 😉 And say you have degrees and diplomas and diplomatic immunity, dont say engineer tho, seems they're not well thought of 🤣😂🤣😂🤣
Carriage bolts do not require and should not have a washer at the head end. The head is designed with a square shank so that it burys in the wood and does not rotate. A washer defeats that . Washer is only used on the threaded end under the nut.
1st time I saw this channel... mind blown by how he went straight to the point, and delivered great information that was well explained without making me feel like I was missing out on life while he talked. Well done!! Subscribed, and look forward to checking out the other vids.
there's more than one way to skin a fox. .. but the right way is the way that is still holding years after the check has cleared. I'm a big fan of the notch method. you can't argue with this point load strength. However, I did notice a valid argument of cutting the notch 1/2" shallow to accommodate for shrinkage. thanks for the vid. I probably would have run the lag screws prematurely!
Span of a double 2x6 beam is limited to about 6', so each post would have about 36 square feet of deck it's supporting. Deck loading is typically estimated at between 50 lbs and 100 lbs / square foot (higher in some locales). Deck load on each post would then be between 1,800 - 3,600 lbs. Load capacity of the 6x6 post is 20,000 lbs. Standard deck footing on clay soil is load capable of about 5,000 lbs per square foot. Most guys put a 12" circular concrete footing under each post, or about 0.8 square feet. So the footing would be rated at 4,000 lbs. Shear strength of even cheap 1/2" carriage bolts exceeds 10,000 lbs, and there are two in the beam, for a minimum capacity of 20,000 lbs, typically closer to 40,000 lbs. Results: the concrete footing in clay soil exceeds capacity estimates of the deck by just +10%. The 6x6 post exceeds capacity needs by +300%. The carriage bolts have a safety margin of between +300% and +700%. The doubled 2x6 beam is right at capacity in this "design," and is the weakest point. Expert advice would be to increase the beam to doubled 2x8. Notching the posts adds some strength, but only to parts that are already the strongest part of the deck in this video.
If notched method, best to notch both sides for a beam on either side, by putting both together you dont allow air to dry out when they get wet. Have seen many of these needing replaced because the rot between them from always holding moisture
It was pretty much what I was expecting to see for exactly that reason. I'd have thought it would be better to allow free air flow to around as much of the structural timber as is possible. And particularly so where said structure is potentially going to be out of sight or difficult to access in future.
I would always notch out but for smaller decks would use the carriage bolts and use a 2x4 support underneath the load for additional support. There is a few ways to skin a cat as long as your not breaking code
@@guywalker5205 No, it IS wrong. Its an engineering and Code (lawsuitability) failure. A lot of people luck out and don't get bit, its from the majority of others failures that proved it was a failure which is why it became 'bad practice'.
ok, am a 30 + yr experienced carpenter/builder on an island ,in a resort town with a boat building industry and of alot upper end homes where quality, code are a must, we are in a hurricane zone. Many VERY GOOD wood workers, shipwrights, joiners, carpenters, cabinet makers here. Cudos to you, very few carpentry videos on RU-vid impress me... BUT FINALLY some one doing it right..... great job
In theory the washer is smart since you don't need a real bite on the wood and it will create less splitting pressure. It just need to hold it in place right?
@@colbornfarms4849 i agree. But at the same time there is no harm by it being part of this particular system.."might" actually have benefits of holding it in place with a bigger head surface
As far as the skill saw issue, SKIL was the first company to make a widely used citcular saw AND in the US the name SKIL became a generic name for this type of saw. My dad called them skil saws and I still do.
I am an engineer. I know what shear is. Those bolts are in double shear. They get to add strength. The area of a 1/2" bolt is 0.2 sq inches. The cheapest steel is good for over 100 ksi. So 20,000 pounds per bolt shear, but double shear is 40,000 pounds per bolt. Two bolt s 80,000 pounds. That is 5 big elephants. More elephants of average size. When he breaks off the screw, he loading a cantilever. That is not shear.
even five 16 penny nails will take over 800LB before they will shear? With that said I do exactly as the video described notch out and then I nail them in place.
@Clark Magnuson, I understand where you're coming from, but you left out the possibility of wood failure as the cause of a deck collapsing. Shear value is meaningless and has no effect in that situation. Why take a chance on just a bolt to hold up a support beam?
I've seen a lot of people argue for notching. I just don't buy it. I understand the argument that carriage bolts are designed for shear strength, but they never seem to address the fact that there are usually two carriage bolts at each post and they are really thick. It would take a tremendous force to shear both of them simultaneously. Also, they are under constant tension - they're basically squeezing the post which means you would have to overcome that friction as well. Not to mention how the joists are connected to all the other framing members including the decking material. Just seems like bs to me.
@@daviddou1408 Designed for use with square-neck bolts such as carriage bolts, these washers have teeth that dig into wood and other soft material to prevent rotation.
Someone already mentioned this, but I would think the problem with the first configuration is that the beam will crack horizontally long the grain and in line with the bolts way before the bolts shear. I like your solution just fine.
Simplier to set the beam on TOP of the post and use either a tie metal plate or nail/screw/bolt a 2x6 on either side of the post to build a pocket. 30 years later with treated lumber my deck is still standing !!
Kudos to you to show the CORRECT way to do it! Sure, you can just bolt the 2x6 to the beam, but wait till a “big wind” coms along. So many “PROS” just want to do things the fast way, not the correct way!
What are you talking about ... "no shear strength"? Those two 5/8" carriage bolts have a MINIMUM shear strength of 73, 300 lbs ... 36 TONS, which far exceeds the shear strength of the lumber! Now, I cut shoulders in my post, but I do it for the right reasons. [Most inspectors will fail an unshouldered joint not knowing why.]
It's the wood that fractures, not the bolt. I've seen it. Another problem is splitting the beams around the post. The 2 beams gain strength by sandwiching them together!! Its ridiculous to divide the beams apart. You lose the whole purpose of the beam!!
@@markherman4023I hear what youre saying but thats due more to improper technique. If they're dried and flashed properly they dont get rotten in between and they are stronger together than they are seperate.
What's the sheer strength of the board when it splits across its grain. The joint is shouldered because its stacked on framing, this is the same reason we dont build ballon framed houses anymore. The bolt may be strong but the wood is not.
I have just calculated the shear strength of a 12mm (1/2") carriage bolt is between 56 and 72 tonnes. That is assuming the moving surfaced do not deform I would be happy to use a 50% value for my structural validations. And there were TWO carriage bolts !! You need a lesson in structural mechanics my friend.
Yeah. A 3/8 bolt would take a shit ton to shear. I guess if you are putting a hot tub or have a deck 30foot off the ground, notch it. If the only load on the joist is the deck boards and people, 2 3/8 bolts will out last the wood.
The carriage bolts could be fine in that configuration, as long as one respects the ratings of the bolt. But then again, I think resting the beam on the post is better because over time, if the carriage bolt rusts and weakens, the safety won't be compromised as quickly.
It's simply code to not hang beams off of bolts. The safe shear strength of those bolts is over 1,000 lbs each but then that assumes that the wood never fails with the point load. It will rarely be a problem, and for a deck a few feet off the ground, who cares but the inspector......but you'll care plenty if someone has the authority to say you have to redo everything properly.
At the corners or our second-story deck where the two courses of double rim joists meet at a 90 are are set on a single notched 6x6 post, which is notched on both outer edges to hold the two courses of double boundary joists. This L-shaped notch leaves a 3x3 section of the beam on the inside corner of the 6x6 and the joists resting on the notches. All secured with nails and no straps or ties of any kind. I'd like to run some ThruLoks through the joists into the post for additional support but only that 3x3 secion of the beams remains as backing for ThruLoks that would need to pass through it from both sections of joists.
Funny, all the decks I've seen like this, I've had to repair due to water damage or dry rot in the area you cut out. Great place for water to settle in.
@Brian Van Horne would just end up rotting your beam prematurely. Just use a post saddle on top of a post and sit your beam on top, besides a double beam doesnt pass code here, has to be a triple and either would using deck screws either
This is what I only ever used to use concrete stumps. The bearer sits on top threaded through the steel out of the stump itself. I’d still rather see a deck built with the bearer notched in that putting the whole load weight on the shear strength of the coach bolts
When you cut the pressure-treated do you need to re-coated copper Green or some other type of sealer, I’m in California and we just use beams on top of the post with a bracket between.
Using washers, right on ! This improves the clamping force out of sight. I also wipe the bolt shaft with grease to stop the galvanising being broken down by the chemicals in the wood treatment. Thumbs up and thanks .
There is a big problem with that construction that most contractors miss. Wood shrinks along the depth and width dimensions but not really along the length dimension. By having the top of the post flush with the top edge of the beam the post end will end up above the beam edge (after the wood shrinks) and a bulge or crack will appear in the decking laid across the area. To do it correctly the top of the post should be about 1/2" lower than the beam edge to allow for shrink.
Wood, especially wood used outdoors, grows and shrinks seasonally (expands and contracts). Over time it does become more and more stable but it will still "move". To prevent expansion and contraction, from being an issue, I recommend that you always set the beams/joists higher than the top of the posts.
sure, if you got a month, but then it will swell again first rain. What Jason Lake ALSO did wrong is not keeping the post top down from the top of beans about 3/8". If beams shrink post will push deck plank up and that will be a real bitch to correct, and really piss off an owner. MAYBE lumber shown is treated not to shrink but should still hold post down @@vinceking7878
I did a quick google search and the shear strength of a 1/2 carriage bolt is almost 1500lbs. With 2 bolts thats 3000LBS of shear on any given point load. Unless you are planning on having an elephant fight a rhino on your deck, the carriage bolts will be sufficient. That being said, I use at least 4x6 post for every deck, pergola or fence that I make. I use pockets or bridle joints for all of the point loads. I usually pin my beams to the posts with dowels rather than carriage bolt, but the idea is the same. I do this for 2 reasons; 1) If you can build with with proper joinery, its always stronger and there is zero opportunity for rust; 2) I use it as an aesthetic quality. The post and beam/timber frame look awesome!
@@chrisburns5691 correct! NOW the bolts only job is to hold the ledgers on to the post, NOT take the load of the deck, the post is taking all the load.
You can get stainless carriage bolts. So let’s drop the rust issue. The carriage bolt has 33,000 psi shear strength. Using the correct amount and size of bolts. Provides plenty of strength. The wood will rot first and for pressure treated cutting to make the nest is opening it to rot sooner Note I’m getting ready to replace a 32 year old deck. It is the cut edge rot that is necessitating the replacement.
while I agree that either way is probably jusy fine for regular loads, if you load a deck with a hot tub, you definitely have to notch your beams into the posts like the video. Same if you were to have a large number of people.
I completely agree that is the way to do it, for several reasons, but I think the shear strength of 2x 3/8" carriage bolts is more than enough to support the mass of a small part of a deck!
I am a 40 plus year builder and you are wrong about this issue. Never double up two 2by6s under a deck. They trap moisture between the board and rot in a few years.
It's not actually in shear. The bolt provides clamping force which creates friction resistance. This is how a lug nut/stud works. They are only in tension. Anyone who's had a lug nut come loose knows the wheel comes flying off very quickly after that. That said wood is not like metal, it will wear in and that clamping force will decrease. The problem then isn't sheer force it's pull out force. Think of how little that carriage bolt head is. The entire force is being placed on that. That's why all thread with washers on both sides is better. Even then the way he shows is good insurance. It's only better to use hangers and not cut out a bunch of wood. He's effectively creating stress concentrations and putting shearing force on wood grain. That's a bad idea.
Wow. Yes, the carriage bolts are stronger than the wood will ever be. Yes the method shown is better. Yes, the 'wrong' way will last for many decades. Yes, the bolts are in shear though there are tensile forces also acting on it. That said, the 'right' way will not sag relative to the post, and will not cause a lump in your floor. The 'wrong' ways point of failure will either be the horizontal grains in the wood splitting or the lumber deteriorating.
@@mjones2431 Something can be said for spreading out the load over a larger area on the supporting post. Green lumber can shrink placing the load on the bolt which is only a fraction of the area resting the weight on the top. Much depends on the load it is expected to carry.
@@chrisburns5691 To be fair, it probably depends on application. Those carriage bolts looked to be about 1/2" and combined would have significant strength. This is the wood equivalent of a rivet. Now if you have a large deck that needs to support thousands of pounds, not the best way. Small deck designed to hold 4-8 people, probably just fine. Also, I don't like notching the 6x6 on the side. Now the load is only put on one half of the post. Furthermore, there are better attachment options out there.
@@SpaceMonkey2385 i agree that they would be strong enough, my point is that they wouldn't pass code. My preferred method when I've built decks in the past is to rest beams on top of posts, and attach with appropriate hardware. Notching is better than just the carriage bolts, as the point load is transferred directly to the solid bearing of the 6x6. Still I prefer resting the beam on top, when I've built decks in the past. As a carpenter I've learned what will pass an inspection and what wouldn't. Supporting a beam off carriage bolts alone would not pass an inspection, at least around here.
@@chrisburns5691 🤣😂😂 it passes code everywhere I’ve ever been. The other way is fine depending on application. Some engineers want it done that way when you set porch posts.
@@15gatorpatriot interesting, doesn't meet code anywhere ive worked, and definitely not common practice. Typically set beams on posts. Would never fly for a 2nd story structure.
Now, I'm just a 30 year in the trade electrician with my state contractor's licence C10 with 16 years as a commercial industrial journeyman in the IBEW. I don't know a lot about framing except that I have to bore holes through it and notch it sometimes. But, doesn't using a carriage bolt and putting a washer on the head end defeat part of the purpose of the design of the carriage bolt? Meaning the square portion under the head of the bolt is there to counter sink into the wood to keep it from spinning and to help it bite when tightened? I may be wrong but, that was always my thought.
@@jmjn916 ---- a lock washer keeps the nut from loosening and backing itself off the bolt that's a lock washer's function. Same with a locking nut with the acorn shape and the nylon plastic inside on the threads. Both keep the nut from backing off. The main point of a carriage bolt is to have the tamperproof head with the square on the underside of the head to sink into the wood when tightening the nut on the carriage bolt.
While your method my be code and perhaps a stronger way of construction. I've seen many many decks and never not one single time has the failure of the deck been due to the carriage bolt sheering.Its always rotting wood,splitting wood, or some other reason but never has it been due to failure of the carriage bolt.
But when the wood gets older the pressure on the holes around the bolts may brake and cut through the beam. The method he showed is much more durable but for a different reason.
@@Sauromannen yeah definitely prefer his method. But he was saying basically that the bolt couldn't handle the sheer strength, which ain't really accurate. As you said the timber would probably fail first.
Your correct, it's not that the "carriage bolt" doesn't have sufficient strength to resist shear loads... it's the wood that will fail. Such a statement in court would get you laughed out... such a statement in the work place will get you kicked out.
If you place support posts within 6'-8' apart, double your support beams and use 1/2" carriage bolts they can hold a lot of weight for many,many years. Remember, proper care of your wood eg stain sealers will protect your deck for decades!
Quite a revelation that the shear strength of steel goes to zero when used in carriage bolts. A lot of structures around the world are going to collapse.
Any structure that relies on the shear strength of any fastener deserves to collapse. Please provide the blue prints the the structure you say relies on the shear strength of any fastener.
@@logicalspartan carriage bolts don't rely purely on shear strength however. It's a combined factor between the compressive strength, shear strength, and the nails you always also add. The video is literally saying 1/2 carriage bolts have no shear strength, and that's grossly incorrect.
@@logicalspartan As a structural engineer, I've designed quite a few structures with only bolt shear. The steel manual gives two ways to design with bolts: using bolt shear and using friction. They even go so far as to show a difference between bolt threads in the shear plane or the bolt shank in the shear plane. The Aluminum Association manual doesn't even show friction connections, because aluminum doesn't work that way. And yes, quite a few people design entire structures out of aluminum.
I built my porch/deck with concrete uprights with a shelf on two sides . I ran a scrap of 1/2" conduit through the form for the bolt to hold the joists sandwiching the uprights . I poured the columns in '83 and have replaced the decking recently and the concrete is still in great shape .
When you notch the post as the person did you reduce the ability of the post to withstand racking by half. By using the bolts you increase the ability of the post to withstand racking. The shear strength of a 1/2 galvanized carriage bolt is in the realm of 8000lbs. So x2 you looking at 16000lbs per post. The Electric utility industry uses 2 5/8 galv machine bolts to hang a 5000lb regulator and it will withstand cat2 hurricane force winds.
@@MrDavidBFoster Michigan. Humidity varies a lot depending on elevation and vicinity to bodies of water. Wolminized lumber works just fine with the 1.5 notch. It expands and contracts, but things won't shift if you take the step of popping some galvanized spiral nails through the 2× before cranking down the carriage bolts.
One point I have is when wood is pressure treated I believe there is less treatment on the inside of a large post so really you are opening up the wood to rot . Second the wood is also smaller after being cut to resist torque and twisting and drying ,cracking ,spilting and will absorb more water and not dry as well.
there is an amazing amount of shear in a 5/8 bolt. where the weakness is is in the wood. with the bottom of the beam having no bearing it's the bolt that will actually split the beam, over time, causing it to fail.
🤣😂😂 in most areas it definitely does meet code for a deck or a porch post with an overhead beam. I guess we need to throw away our contractor’s books and get rid of engineers.
Regardless if the bolts can adequately carry the load or not, incorporating the notch is technically the correct way to make this connection, especially if the structure is utilized as a public space. Another important design consideration: when making the notch, the builder/designer should leave enough material thickness on the post as to not compromise the structural integrity of the connection. Additionally, if the structure is used as a public space, the connection should be (in my opinion) supplemented and strengthened by implementing steel "T" plates.
There is nothing wrong with the bolt through. I’ve built several (at least 6) decks in my lifetime using the bolt through method. Some that I can still visit after forty years, are still standing. Repairs have been made in some but the bolts are holding up pretty good, a little rusted, but good for more years. One thing I do not do is lazy up and use foam for the post foundation. Put a little more time and effort into your deck and build you a solid foundation. Use sakcrete. The combination of a solid foundation and a bolt through system will make your deck stand solid for longer than you might want. Let’s dig!
My deck was a foot or two off the ground, see no problem using the "wrong" method. Even a grade 1 bolt has a load rating of 33,000 psi. The problems are water intrusion and aging of the wood from climate cycles. Ancient wood building constructions withstood many hundreds of years without any metal fasteners. In contrast my decks only lasted 30 years with screws, nails, and bolts.
I wonder if he first tried to break one of those carriage bolts. Can you imagine how much force that would take? The wood would fail far before the bolt shears
@@RichardMiller-tq6ut around 5000lbs shear strength on 3/8" carriage bolts. So with 2, you're looking at 7500lbs-10,000lbs of weight you can put on that beam before it might snap. So unless you're planning to drive a big truck over your deck, it's probably fine.
When a wood face touches a wood face and you clamp them it creates friction. Think of how a rim is clamped to a wheel hub. The studs aren't getting a shear load, instead the load is being transferred by friction. Therefore the studs only experience a tensile load.
Agreed, but over time the wood compresses under the bolt head, and the preload is greatly reduced, if not lost completely. Then the friction clamp load goes away.
@@rossgalbraith3878 very true. This is why when I clamp wood I build a metal plate with 6 or so bolt holes. The clamp area then is so large that you don't get this issue. I try to avoid that as it's costly but in some places it's the only way to get it to work.
I agree with Clark. As an engineer, I can tell you that there is plenty of shear strength in those half inch bolts. However, I would definitely build the post and joist the way this guy does, by notching the post. It's just better and tidier.
Hey Jason, doesn't the friction from tightening the bolts carry the load, not the shear stress of the carriage bolts? I do appreciate the notched version also.
That's a good question! But, what happens if the wood shrinks as it dries. No more tension, no more friction. Then the bolt is loaded in shear. Soooo...I would say no! Technically, the joint would be statically indeterminate. Because we don't know how much of the load is carried by friction and how much by shear. Although, we usually assume friction less joints in statics.
@@markflierl1624 .......wood shrinkage compromising a friction grip is a good point and the sort of detail I'd consider these days . As a teenager I built a big tall shed by bolting all the timber together. I thought ten years would be good lifetime for it. Sold the property thirty years later with the illegally built shed still sitting firm..The Australian eucalyptus timber was dry and the environment was high humidity leading most likely to timber swelling slightly.. I had to use bolts and drilling cos it's impossible to hammer nails into the dry timber. The timber shown in this video doesn't look like serious construction timber to my eyes.
@@markflierl1624 Firstly,some of the wood pinched between the bolt and nut is crushed so cannot shrink any further. Secondly there is nothing to stop you re-tightening the bolts after say 2 years. Thirdly never rely on fixings alone because then you are one timber /fixing defect away from structural failure. Even a 1/2" notch will impart incredible additional strength to the structure.
I built mine 12 years ago the wrong way, with just wood screws and it hasn't moved an inch... then again I don't need a deck strong enough to park a car on either.
I was just thinking about this issue and this video popped up on my phone. I will try it out and see. Always used carriage bolts and cantilever method. Maybe I can now drive my car up on the deck with my pet elephant. Seriously. Nice having options.
I’m planning to build a deck for my dad. About 12 feet off the ground at the highest point. Was planning to sandwich three 2 x 6 joist’s and just set them right on top of the post after coating them and polyurethane, then gluing and screwing them together. I was then going to sandwich the posts with additional 2 x 6 boards to hold the joists on top. Fill in the gap with piece of plywood and then set a single carriage bolt through on the top of each post. And then one bolt in the middle and one bolt at the bottom. Planning to use bigger than a half inch carriage bolts. Maybe 1 inch stainless steel if I can find them. Not sure about code though. Might use a rubber membrane on top of the joists for extra protection.
I prefer to notch on both sides of the post leaving the middle piece and lag bolt through. Gives more of an even bearing down on top of the post and a wider area for supporting the joists. Edit: Also lag bolting to the side of a post is not correct because you are relying on the strength of the bolts to support everything. The post itself is supposed to carry the load not the bolts. The lag bolts are used simply so the beams don't pull apart from the posts.
***** How so? a beam or joist will be laid into the cut notch covering everything. If you are really worried you could use some wood preserve or sealer on the notch but it's unnecessary. When they treat the wood it gets absorbed into the wood also.
Can’t tell you how many times I’ve been in arguments with inspectors and contractors over this supposed better way. First by notching the post you severely increase the chance that it will split and fail anyways in the near future. Second the wood would bust before shear off a 1/2 galvanized through bolt and there are 2.... I guess I will always build mine the wrong way as long as I can get by with it.
Thats because the shear strength of carriage bolts are incredibly high.. The wood around the bolt would start failing before the bolt does. You could always go around under the deck and shore up some wood under the joist and tie it into the post if there is any sagging etc or wood failure.
@@RSoles-hz9nc The trouble I have seen with through-bolts is that they invariably loosen up causing the post and joist to drift out of square, not to mention that where I live inspectors would fail them every time. The ones I see are usually on homeowner or brother-in-law decks that were never permitted. Are you making sure your layout is square, and do you use a plumb line to determine pier location before locating and measuring the posts? That is how I do it and although it is not perfect (what is?) it always gets me to within about half an inch or so for the post location which is close enough for the pier, then I measure the location for the notches after determining exactly where the rim joists will be located. I also use scrap lumber to do a mock-up especially for larger decks and that helps. I'm not trying to insult your intelligence, just trying to be helpful.
The point missed here is if the bolts are properly tightened, the pressure exerted on the post from the two sides developes a lot of friction. That friction is a major contributor to the weight carrying capacity. It isn't just the bolts. It's the assembly in it's entirety that becomes stronger than the components could ever be when considered separately. The notches aren't a bad idea, but I don't think they're as necessary as stated either. Jmho, fwiw, ymmv, etc.
I've been trying to make a loft bed frame and I very rarely see this principle of putting the beams on top of the posts being followed in youtube videos. I don't know if this is required for things like beds that won't hold so much weight, but it seems like a sound principle to follow regardless.
Attaching a beam to a post face mounted with through bolts isn’t “WRONG.” It all depends on how much weight the beam is supporting. It’s perfectly acceptable to face mount and through bolt a beam for light duty residential applications. Accordingly, It’s spec’ed that way in the IBC as an acceptable option.
So the people saying that the carriage bolts won't shear off are correct. It takes a tremendous amount of force to shear a ½" bolt. The other half of the equation, though is support. The carriage bolts are concentrating all the force on a relatively small area of the post (the two holes.) You are also depending on the fibers of the beams not splitting. It may work, but you have much less load capacity. Finally, if you get some rot over time the load capacity of this configuration will degrade much more quickly. (this configuration is also against code in many areas - there's a reason why.) By putting the beam on *top* of the post, you distribute the load across the entire surface, do not have to worry about the beam splitting and do not loose strength as quickly if there is rot around the bolt holes.
