# Lateral Tension Device



## Keystone (Jun 25, 2012)

Came across this today.

View attachment 1705


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## ICE (Jun 25, 2012)

So what is the purpose?


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## mark handler (Jun 25, 2012)

Dont know what its connected to?


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## Keystone (Jun 25, 2012)

2009 IRC R502.2.2 Lateral Load Connection for a Deck

After a bit of surfing around I came across this article among several others, worth the read.

http://www.deckmagazine.com/article/252.html


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## Keystone (Jun 25, 2012)

It is an exterior 2nd floor corner deck (two faces of the deck having a house wall) with the interior joists running perpendicular and having the lateral tension device installed.


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## ICE (Jun 25, 2012)

Keystone said:
			
		

> It is an exterior 2nd floor corner deck (two faces of the deck having a house wall) with the interior joists running perpendicular and having the lateral tension device installed.


Is the installation correct?


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## mark handler (Jun 25, 2012)

Is it installed correctly? Questionable

Will it work? Probably

As a Licensed Design Professional, I would not have put in the third bay.

And I would have used 4x blocking


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## DRP (Jun 25, 2012)

No it is not installed correctly, blocking all the way to the wall, but it is also not needed on this deck.

"It is an exterior 2nd floor corner deck (two faces of the deck having a house wall)"

The house corner provides far more than 1500 lb lateral restraint.


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## GBrackins (Jun 25, 2012)

just curious, what is the finish surface of the deck? I noticed the sheathing on top of the joists.


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## Keystone (Jun 26, 2012)

The material above the deck is plywood to provide a temporary walking surface.

Initial thoughts, inspection failed but with-held until I could do some digging.

My conclusions followed suit with comments above:

First, provide suitable blocking to the ledger board

Second, blocking may not be needed due to the to house surface connections.

In realization I understand that the deck does not appear to require tension rods, blocking, etc but I am not an RDP so what can I cite to back my position, AHJ???  Additionally, I was considering requesting each corner be tied together by corner plate or similar to provide a positive box frame but again I am not an RDP and frankly it may not be necessary.


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## Builder Bob (Jun 26, 2012)

WOW! Something just doesn't seem right...


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## Big Mac (Jun 26, 2012)

DRP said "but it is also not needed on this deck.

"It is an exterior 2nd floor corner deck (two faces of the deck having a house wall)"

"The house corner provides far more than 1500 lb lateral restraint."

This appears to be an opinion.  I know of nothing in the IRC that says the 1500# anchors are not needed when two sides of a deck abut the house.  I'm not saying that it is not possible that the connection may be adequate, just that it is not prescriptively recognized by the code.  Also one might argue that if the corner deck is large enough, a 1500# anchor might be required at the outside edge of the deck in each direction.


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## dhengr (Jun 26, 2012)

These prescriptive codes are driving me crazy.  We will never be able to prescribe the perfect magnitude for loading or whatnot and the perfect detail for every conceivable condition that someone could come up with.  Someone who knows what the heck he/she is doing has to be able to make a good sound engineering judgement about something like this, and many other details and conditions, not specifically covered by the codes.  We shouldn’t be leaving this kind of thinking and decision to weekend carpenters or inspectors who don’t have a handle on the engineering concepts involved, nor can we codify every possible condition.  The fact is that the codes don’t cover decks very well, and in part that’s probably because they are just too difficult to put into neat little design groups, like tabulated fl. jst. spans.  The majority of decks just need some good common sense (which is all too uncommon, read the damn manuf’ers. instructions and footnotes too) and some good clean detailing to be just fine.  There are also hundreds of variables which can really change the picture.

How are those ledgers connected to the bldg. and through how many layers of foam insul., etc.  The connectors (nails, small lags w/o washers?) look pretty small, with large spacing, and the top connectors are too close to the top edge of the ledger.  I think I still see the corner trim for the vinyl  siding, at the ledger intersection.  The ledger should be against the bldg. osb sheathing and flashed behind and over the ledger.  What I see in Keystone’s picture is something the guy heard, needed doing, but with no understanding of what, and why, and where.  If needed, I would put that type of lateral tie hardware a few feet from the outer edge of the deck, where it is much more effective.  DRP is right in several respects: I would continue the blocking in the two open jst. bays to the ledger; and if this is just an 8x10 or 10x10 deck in the corner, this type hardware is probably not required.  The 2x10 blocking is just fine for this purpose, obviously the connection inside the bldg. must be adequately made and blocked too.  And, that is tough to do without ripping up flooring so you can nail the blocking to the subfl. and so you can install the blocking, and so you can double the nailing at the sub.fl. to the rim jst.  Obviously, this can be done easier on new construction when you know you will have a deck.

Here is some of my engineering logic on the picture and the comments so far:

1.)   The hardware installed so close to the jst. hangers is a waste.  There is most likely sufficient lateral resistance on that end of the jsts. through the jst. hangers.  Jst. hangers have a good gravity and lateral load cap’y., but aren’t worth a darn in pull-off (from the ledger) along the length of the jst.  For the hardware to be tightened so it works, it tends to flex the two jsts. laterally, and the only thing which prevents this is the two nails/screws in each deck board in that immediate area.  Thus, the want for blocking back to the ledger, to bring more deck board/jst. connections into play and to allow me to tighten the threaded rod.  The deck board over the blocking should have a few more screws down into the blocking also.

2.)   The idea that the deck is adequately supported in the exterior house corner goes something like this...   it has two properly affixed ledgers and properly attached jst. hangers, etc.  Then applied lateral loads (particularly wind) in the N-S or E-W direction are taken into interior fl. framing in compression and really can’t be applied to cause much tension at the deck jst. hangers.  But, with EQ or crazy people loadings, out near handrails, you can get this tension loading, and that’s why I would like the hardware within a few feet of the outer edge of the deck in each direction.  There are many details and conditions which might complicate this need for lateral tie-back, that’s why the need for some experienced judgement, not a simple prescription.

3.)   On a simple 10x14 deck which extends out 10' from the ledger/bldg. there isn’t real much chance of lateral loading problems.  The worst case is a large lateral loading out near the handrail, and I do worry about a bunch of drunk football linemen all swingin to the same music out there.  If the deck is off an upper level bedroom you probably wouldn’t be having the same kind of party on the deck.  If you have screen walls you can pick up larger wind load components.  Otherwise, you have the face area of the rim jsts. and handrail system exposed to the wind.  I am usually very conservative on this issue and consider the face area of a bunch of regular jsts. too, since the wind will curl up under the deck too.  And, you can have wind uplift of the deck.  Then, I consider the deck system as a semi-rigid diaphragm, it will rack quite a bit, vs. an osb diaphragm.  Thus, one corner of the deck is in compression into the bldg. and the other is tending to pull away from the bldg. at the ledger.  Thus, the possible need for tie-back hardware.  I like to put the hardware on the 1st, 2nd or 3rd interior jsts., or about 3 jst. bays into the deck system so as to bring adjacent jsts. into play through the deck boards.  I want to maximize the lever arm for this tension reaction from the corner in compression, but if I put the hardware on the rim jst. or even the 1st interior jst. I don’t get very good load distribution to adjacent jsts.  Again, obviously, a proper connection has to be made inside the bldg.  And, we don’t always know which deck corner will be in tension.  EQ’s and other details complicate this discussion further.  Also, if the deck is 10x20 with a 10' ledger on the bldg., then the potential lateral loads can be applied much further away from the ledger, and my resisting lever arm is much smaller in proportion to the 20' deck cantilever length.  Obviously, some serious tension tie-backs near the corners becomes important.  Also, the lateral loads in the N-S direction tend to be taken out near (or at) the E-W edges of the deck.  So, on all decks you should consider what to do in the way of bracing the outer (or all) posts so that they can take these lateral loads to the foundation.


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## Keystone (Jun 26, 2012)

The ledgerboard fastening is an issue that is also being dealt with by the owner, it is relevant but for this thread I am fixated on the tension rods. The ledger is fastened by FastenMaster ledgerloks, http://www.fastenmaster.com/details/product/ledgerlok-ledger-board-fastener.html

The tension devices are installed at each 1/3rd of the deck. The deck is 14' square.

The white item in the corner is from the housewrap, proper flashing and counterflashing also addressed.


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## jwilly3879 (Jun 26, 2012)

For a 14' span with 40 psf live load the ledgerloks should be no more than 10" oc, these appear to be more like 16"


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## DRP (Jun 26, 2012)

Big Mac, yes that was opinion, I said "not needed" rather than "not required", things are sometimes required that are not needed.

Keystone, I'm unclear, are there 2 ties or 4?

dhengr, I agree, but I think it would take one heck of a party. I hadn't looked deeper than the hold down connector, those upper ledgerlocks are above the hangers, tension perp to grain. There was a picture a few years ago that made the rounds of the trade mags. The narrow ledger strip above the hangers was still attached to the wall, the bottom 3/4 of the ledger was still attached to the largely intact deck on the ground. In that case all the lags were above the hangers in a row.

Let me try another thought out. We are required to have 2 ties, the hold down and rod is one suggested tie but not the exclusive method. The right hand ledger is our tension restraint on that end of the deck, count bolts and I'll bet the 1500 lbs shear is there. Only one more is "required" near the left end of the deck out of view. It would be in line with the joists. I'm looking at the right hand ledger as a posted end only and the connections to the wall as the lateral connector in the joist direction with the other required connector at the "free" end. No tension connection would be "required" in the cross joist direction in a conventional single ledger deck and so none would be required here in that direction. We may need one in the cross joist direction but I don't think one could be required. On that conventional single ledger deck there is nothing but air out there on the right. The geometry is already superior to code and then it sounds like we want him to go a step further and put a tie to the wall on the right.


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## Keystone (Jun 27, 2012)

DRP, Two ties are in place, the ties are spaced at the first third and the last third of the deck. The outermost corner is supported by an 8" by 8" post with the header cut in (saddled) and secured by thru bolts.


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## Builder Bob (Jun 27, 2012)

The big question that I have an an uneducated person (not an engineer), A field inspector made the right call by questioning the installation since the tensioner (as installed) appears to not have the ability to draw the load towards the ledger -------


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## Big Mac (Jun 27, 2012)

dhengr - A little more food for thought.

I would agree that anchored correctly with enough bolts from the ledger to the rim joist, that the anchor bolts would likely provide an equivilent to 1500 pounds laterally.  However it is the deck we are attempting to anchor, not just the rim joist.  Will the joist hangers or other connection from the joists into the ledger also provide 1500 pounds, whether those connections are resisting lateral or withdrawal forces?


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## Keystone (Jun 27, 2012)

DCA6 and MMI allow installation of tension devices in a case such as pictured, deck joists perpendicular to the floor framing, but states blocking must be taken back to the ledgerboard. Re-inspection of the deck to occur due to other concerns but learned something new


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## Francis Vineyard (Jun 27, 2012)

Not to sidetrack the issue at hand but there has been a lot of statewide resistance mandating this tension device. Open to conjecture Fairfax County whose original Typical Deck Detail that formed the basis of the AWC DCA 6; has revised their 2009 Typical Deck Details with elimination the lateral tension device and provided alternate cross bracing. 



This has given pause to engineers in our area that were called upon in the past to provide or approve an alternate solution. 

http://www.fairfaxcounty.gov/dpwes/publications/decks/details.pdf



Francis


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## DRP (Jun 27, 2012)

Keystone, You are following the requirement then, I follow the logic. The need as explained be dhengr would be near both outside corners but that is outside of the requirement. I am trying to shake it up a bit to think this through. More to think about, I'm doing more engineered floor systems, open web and tji's... how to attach, may I grab the diaphragm with blocking and sufficient attachment directly to it? And another, I've been working on a house with porches that are on compliant stone perimeter walls. The lateral restraint is already there via those walls, is the device still required or do we recognize that the lateral has been taken care of? Or for that matter are we only talking about decks and not porches.


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## Keystone (Jun 28, 2012)

Francis, good info, in my searches I have ran into some of the same info that is contained in the link such as knee bracing, "K" bracing, wet setting the post into the pier to eliminate the pivot point...

DRP, I think we have to understand why the requirement is in place. IMHO the great engineered products that are so readily available and pointed toward seem to solve one problem but create another. What should be advised is standard construction technics, let the engineered products for the manufactured companies to pinpoint in thier literature as the alternative not the 1st solution.

The points you pose are valid but with them being engineered systems and the potential to alter the proposed intended use they would be required to bear the stamp of someone with greater education than I. Decks vs. porches, this discussions been had in our office and they serve the same purpose so they are one in the same in our view.


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## infoleather (Aug 31, 2012)

Above the hanger on the ledger lock food nervous PERP. There are a couple of years ago, the Round of trade magazine.


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