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I just came from the building department and they now want a 3/8″x6″ bolt every 3″ staggared top and bottom.
1.A 6″ bolt is a little excessive seeing that you’re only going through
a 1 1/2″ledger and an 1 1/2″ band.
2.I’ve been bolting ledgers for years at 24″ o.c. and I hardly think anyones deck will fall away from their house.
3.It’s no wonder my competitors are charging $20 per foot for a deck.They have to buy too dang many bolts.
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Replies
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In our our area, we have have to put bolts 12" O.C. staggered. Although one deck not too long ago, they made us put them 10" O.C. staggered.
*It's those darn weathermen. If they would just quit predicting hurricanes every year then maybe the engineering rules would be loosened. Just look at the the requirements for embedded j-bolts. Went from 12 feet on center to 6 feet to 4 feet and now in our area its 18 inches, 5/8x10 with 3" washer. (It's even required on the backyard sheds). 18 inches ALWAYS ends up located under your 16" stud pattern somewhere so you might as well put them at 16" oc.
*Are we talking lag bolts or carriage bolts here? I like to use both, spaced 16"o.c. alternating lag and carriages. I also use hot dip galv. although most decks have the zinc plated. I have pulled lags out that were only a few years old with the threads almost rusted away. If you think about it, decks are a relatively recent phenomenon, in that its a wooden structure with no protection from the elements. Very few get the maintenance they need to maintain structural integrity. Almost none are ever inspected to see that they are structurally sound. Add to this the fact that they are frequently overloaded due to there novelty when entertaining. One think I make sure of is that the ledger will not come apart from the house. And that it is flashed properly. Overkill is good.
*The reason they've tightened up so much around here is because some bad contractors installed some decks wrong and there were collapses where people were hurt.
*every three inches- o.c.? where's the wood gonna go? so you gotta put forty lags in for every ten feet?ouch...on the upside it could be a boon for the steel industry.
*Pro-dek, are you sure its every 3 inches???
*JimL-Yes it is called out and shown as follows-Ledger to be same size as joist,min.2x6.Attach to existing rim joist with 2 rows of 3/8"x6" lag bolts and washers spaced at 6" on center and staggered as shown.Two top bolts 6"on center one bottom bolt at bottom between two top bolts.This is developed in cooperation with City of Kirkland,Bellevue,Redmond,and Issaquah.This equates to six bolts per foot which is nuts. No "pun" intended. Are we getting engineers from Tornado alley?
*Talk about pathetic overkill. I usually use carriage bolts at 16" oc, thought that was plenty.
*We use double Timberlok screws, spaced every 24". We try to get them into joist ends if possible. And we just "redid" a deck for someone who had a collapse. Whoever built it (and I'm thinking a friend of a friend of a friend for a REALLY good price sort of thing), used 3" deck screws. Something like 20 over a 16' span. And of course there were the missing joist hangers. And the insurance company telling them to get lost...But 3" OC? I think I might challenge that one.
*Do you think that Simpsons hardened 1/4" screw, with a cap or washer, built-in, would substitute? we are using these in column caps and buckets now, instead of through bolts. Since it is a hardened, tested and engineered product, maybe you could substitute enough of those to replace the lags. I'd get an engineer to draw up a substitute attachment that I liked, and then I'd take that drawing into the city every time I needed a deck permit.But then, I wasn't remembering that you work on the eastside, where the inspectors regularly make arbitrary additions and changes to engineers approved drawings. Built a deck last year at $68.57 per foot. He was happy, too. We have to find those guys more often, and then we'll put so many lags in no wood will be showing.
*Man Jason,Although the timberlock screws are rated at something like 1000# in shear per the information on the box, I don't think they are adequate for deck loads. In the event of a collapse, I think that withdrawal, not shear is the failure. That's why I don't rely on lags only for attachment.I am also not sure of coatings like those on the timberloks. Back one out and I'm sure you will see that some has rubbed off, opening the door for corrosion.Could you determine where the failure occured in the previous deck collapse?
*Tommy, I was pretty sure the box itself specified a higher shear strenght for them. I took these through the inspector, who didn't have a problem with them, and was in fact pretty impressed (most people around here just buy whatever the lowest grade 3/8" is; and yes, I've seen rust on those in short times). I'll look at box tonight and see what it says, but it didn't seem to bother him; but, if I ain't doing it right, I'll surely change! Anyhow, the deck we just "fixed" sheared right off the wall; the deck screws holding the ledger on were all broken except for a couple that pulled out. The rims sitting over the beam were toenailed with deck screws, but that was the only attachment to the beam, so the whole thing just seesawed right on down, pushing out as it went. Also, you said that you don't rely on only lags for attachment; how else do you attach?
*I always thought/heard that putting screws and such into end grain was a sure recipe for failure. Why would you want to bolt/screw into the ends of the joists? Seems like getting a good purchase on the rim is the thing to do.... Maybe you're using the joist ends in addition to the rim? Sam
*Here, in NC we are only required to have 1 5/8" bolt every 3' or so, depending on the deck size - and it needs to be nailed. If anyone is interested in looking at the section of our NC/Cabo code that has most of the stuff pertaining to decks, go to this link.Now here's my opinion... our code is a bit lax - I like a more bolts. And nut/bolt/washers are i much better than lag bolts. I don't like lag bolts for hardly anything. And "zinc coated" hardware is junk for exterior applications. HD or better (ss, powder coated, etc) is the only way to go.If you want to see the whole NC/Cabo Residential code, go to this link.Of coarse we are supposed to go to the IBC 2000 next year - that should be a real fiasco!!!
*Guys,It is not the strength of the bolt that counts but the crushing strength of the wood that sits on top of the bolt. If I remember right 1 1/2" of wood held or sitting ontop of a 1/2" bolt can hold 100 lbs. Also a deck is loaded at 60 lbs /sqft.Example: 16 x 12 deck. is loaded to 11520 lbs.The ledger carries half 5760 lbs. ie 58 bolts. 64 for good measure. Therfore for 16 ft of ledger is 4 per foot or every 3".I use 4 1/2 lags for the 2- 11/2" pieces. A lag's pull out is increased if it penetrates through the material.Architects and Engineers jump in now and correct me or if I have been over building for 20 yrs.Ron.
*Tommy, and et. al., the Timberloks are rated for 2995 lbs. of shear, 1450 lbs. pullout, doubled if into end joists. The problem I have with lags is that most of the ones around here are at the low end of the scale for hardness, and although I don't have my "Pocket Ref" book handy, it was much lower. I also don't understand RonK's statement that "A lag's pull out is increased if it penetrates through the material..." We once reframed a deck that had pulled because whoever built it (and the owner's looked mighty sheepish), had run 6" lags through the rim, so that only the bare shaft of the lag was holding; when it started to pull, I imagine the bare shaft just "slipped" out, and kind of pulled everything else down with it. Perhaps I'm misunderstanding Ron's post, but why would you want a fastener of any kind to go through materials and stick out on the other side? Not trying to be argumenative, just pointing out that we do things much differently here; I though Timberloks were the greatest thing since sliced bread, and the inspector did as well. Am I missing something?
*Ron:You say: "Also a deck is loaded at 60 lbs /sqft. "That may be the way you all do it where you live, but not where I live. We build decks (as required by code) to 50 PSF. You also say: "The ledger carries half 5760 lbs. ie 58 bolts. 64 for good measure."I guess you are assuming that the deck is built with a flush girder rather than a drop girder with cantilevered joists? Is that the way you build most of your decks? Just curious.
*Ron K- can you take another run at this? Or someone else put it in terms for the simple minded-aka-me.I absolutely do not follow the 100lbs per 1 and 1/2".thankshub
*Jason,What I meant was that I use lags in conjuction with carriage bolts. I probably use enough of either one.These timberlock fasteners in case any of you haven't seen them at HD are black, powder coated, hardened, hex head screws, similart to a tapcon, and with a similar thread pattern, just not double thread. The box says "do it all wood fastener, no predrilling, they zip right in. Ideal for: fencing, stairs, post and beam construction, exterior decks, carrying beams, header boards and more. Self countersinking head style (cone shaped beneath hex head) Replaces spikes and lags. Pullout strength is listed as 1450 lbs., and average ultimate shear is 2995 lbs.I just used them to attach a ledger for a trellis, but I am still not sure about using them for deck ledgers. 'Course I don't see how those stilleto hammers hit as hard as one weighing twice as much either.So your township guy said you can use them? We are on a job where we are doing a three story stair tower and the township approved the plans as drawn. Now the bozo says they are not resposible for errors, oversights or ommissions, per some code section.
*why not use angle iron and fool 'em
*A 2-by southern pine side member, such as the deck band joist attached to the house framing with a ½ “ diameter bolt and single shear applied perpendicular to the grain for “normal” duration (a factor that includes full live loading but not high wind or earthquake forces), the allowable shear load in the bolt is 330#. Of course, the bolt itself could handle many times that load, but what will fail first is the wood: That’s what limits the capacity to 330 pounds. Ron K., if your deck is 16' x 12' then you maximum tributary would only be 8' which would put 400# plf (40# L.L. & 10# D.L.) of weight on your ledger board, which would need 1/2" Dia. bolts @10" O/C.
*Funny thing about different regions of the country - different codes for different regions, on same structure.Here, it is very rare that we even attach a ledger to the house. We usually build a free standing deck, with the support posts set in concrete about 6" to 8" away from the edge of the house. The deck boards are installed so that the ends are abutted to the edge of the siding material. Of course, we don't have basements, or backfill next to the house foundation, so the ground here is usually undisturbed soil. My question is this - why can't you build a structure that utilizes a beam close to the house to take most of the load that the ledger would normally? Would this not eliminate the load restrictions of the ledger and the bolts? Just curious. Seems like an extra beam would be cheaper and easier than all of those extra bolts.James DuHamel
*James DuHamel-All those stinking bolts would look better than two beam runs under a 12' high ,8'wide,26' long deck. The thing is,the 2x8 joists are only spaning 6'with a 2' canterlever.Now don't you think 2-3/8" bolts every 16" would be more than ample?
*Pro-Dek,I'm stumped by the bolt plan. Why would they say 6" lags? This makes it 3" beyond the 2x ledger and 2x rim! Also, A 3/8" bolt can handle 313# (Doug Fir), so 4 per ft means 1252lb/ft. If King Cty is 60#/sf for a deck this means a 41 ft wide deck! Somethings not right here. DarrellPS. The drive to my office through Duvall was interesting...Beautiful snow on the hills and crazies driving 60mph on Novelty Hill rd.
*Whatever floats your boat.I just don't understand how an extra beam placement could make the underside of a deck so much uglier. Part of our skill is to make things look good, even when you think that they can't.And yes, I think 3/8" carriage bolts every 16" would suffice, as long as the rest of the deck support structure is designed to do its job, and support the load evenly. If the support structure is not designed and constructed properly, all the ledger bolts in the world ain't gonna help.Just a thought...James DuHamel
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I just came from the building department and they now want a 3/8"x6" bolt every 3" staggared top and bottom.
1.A 6" bolt is a little excessive seeing that you're only going through
a 1 1/2"ledger and an 1 1/2" band.
2.I've been bolting ledgers for years at 24" o.c. and I hardly think anyones deck will fall away from their house.
3.It's no wonder my competitors are charging $20 per foot for a deck.They have to buy too dang many bolts.