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Cable railing

Discussion in 'Residential Building Codes' started by Rick18071, Jun 25, 2020.

  1. Rick18071

    Rick18071 Sawhorse

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    In the past I have inspected railings on decks that have horizontal cables. When I inspected them the cables were tight every 3" o. c. so i could not spread them more than 4". I liked the look so when I recently rebuilt my deck I made a cable railing with a kit. I had to buy a hydraulic crimper to crimp the cable to right and left hand threaded bolts that just screw into the 4x4's. The cable started sagging after a few days and I had to tighten them up. This is still going on and I am running out of threads on the bolts to tighten the cable. How can we allow this type of railing if it doesn't stay tight to keep a less than 4" opening?
     
  2. e hilton

    e hilton Bronze Member

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    Rather than screw the fittings into the posts, drill a clearance hole, put the fitting on the far side, and tighten the cable. That way when the post dries and the wood shrinks, the screw threads won’t pull loose.
     
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  3. Rick18071

    Rick18071 Sawhorse

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    I'm not worrying about the cable to tight but rather too loose.
    This is the hardware I'm using:


    deck railing.jpg
    The cable seems to keep stretching.
    I would like to hear from Glen, our deck expert about this. Can we approve a cable railing system if the cables keep stretching after the inspection and causing to have more then 4" between them?
     
  4. e hilton

    e hilton Bronze Member

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    I understood what you were saying. Im trying to evaluate why the cable is getting slack.
    1 cable stretches. Not likely.
    2 anchors pulling loose from posts. Possible, you’re using threads into wood and putting a lot of tension on them.
    3 cables pulling out of swaged fittings. Also possible, if the fittings weren’t properly installed. Were the crimp dies the correct size for the fittings?
    4 corner posts are leaning in because they were not anchored properly. Highly unlikely on this deck.
     
  5. mtlogcabin

    mtlogcabin Registered User

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  6. e hilton

    e hilton Bronze Member

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    They do. But the stretch us ... depending on several factors ... about 3/4 of 1%. So assume a 20 ft run of cable ... 240 inches ... so maybe 2” of stretch. Once it has stretched, might be time to cut off one end and reswage.
     
  7. Rick18071

    Rick18071 Sawhorse

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    I put a mark on the cable at the crimp and the crimp is holding. 2 days ago I cut off one of the crimp/bolt on a 40' railing on one side. It took of 2" of cable off and used a new crimp/bolt on the same cable and tighten it good. Today it's lose again. I wonder how many of these bolts I will need to go through until it stays tight.

    But I mostly posted this because I never went back to the decks with cable railings after I inspected and I did not know they would stretch. Maybe the code should not allow them. The cables needs to stay tight to keep the opening less than 4".

    Your thoughts Glen?
     
  8. steveray

    steveray Sawhorse

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    Kinda the same thing when people don't maintain their wood decks...Our is but a snapshot in time....
     
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  9. tbz

    tbz Silver Member

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    Evening Rick,
    1st off not all cables are the same and nor are the fittings.
    I strongly recommend either using materials from one of these 2 companies.
    I have been doing Cable Railings for over 30 years and these 2 manufacturers do a multitude of different things, but the main thing they do is the quality of the cable they buy and distribute are "Pre Stretched" and as such, eliminates a lot of the continued stretch. Their fitting systems are also way better than all the rest out there IMO. There are a lot of imitation copies, but they are the 2 main stays in the USA. There are a few Sailboat hardware manufacturers that make nice fittings but are a lot longer and harder to work with.

    As noted by others, the deck is another issue you will have with pressure treated wood shrinking, I have seen decks and framed lumber shrink about an inch per 15 feet many a times. I had a deck once shrink almost 1.5 inches on 12 feet over 14 weeks after installation of the railing/guard.

    If you are sure the wood is not moving on you and it is the cable, I would venture that more than likely the cable is not 1x19 and or not pre stretched.

    I am not sure about the fitting you are using, but from what I am seeing posted, the fact that they are left and right threaded and need to be crimped and twisted into the wood to tension and don't machine screw tension like Ultra-Tec or Feeney after being crimped, I would say they are basically a lower quality fitting and that is part of your issues.

    I would suggest purchasing one cable package from one of the companies I noted and comparing them to what you did purchase.

    1x19 SS cable pre stretched in 1/8" diameter should have no issues under 50 feet

    Here is a link to Ultra-Tec engineering on cable tensioning

    http://thecableconnection.com/ultra-tec/design/data-on-cable-flex-in-cable-railing
     
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  10. Rick18071

    Rick18071 Sawhorse

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    Interesting. Never herd of pre stretched cable. The deck is at least 6 years old and should not be moving. I got the cable from a friend that was cleaning out his shed. He thinks his dad put in there years ago. There was a lot of it. His dad worked in the Brooklyn Ship Yards in the 40's and 50's and was known for bringing stuff home that "fell off the ship".

    I could not use systems with a bolt all the way though the post because of no room on the other side of the post for a nut.. I think I will just keep cutting the cable shorter, eventually it should stop stretching.
    .
    I was more concerned of the deck railings I inspected in the past. I wonder how they were soon after I did the final inspection. I hope they were still good by the time they got the C. O.

    Maybe the code should require pre stretched cable. But then the code should also require pre shrunk treated wood for decks with cable railings.
     
  11. JCraver

    JCraver Sawhorse

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    No new code requirement. Not everything that we've never seen before requires a new code to "fix" it.

    You used the wrong cable. I'd venture a guess that most decks you inspect with cable rails don't utilize cable that "fell off a boat" and spent ~20 years in the backyard shed. In the decks you inspect in your lifetime, maybe you'll see where 1 other guy is going to use "found" cable; all of the rest of them, even the hacks and the homeowners, are going to buy a deck cable railing kit - because people are lazy, and the kits are easy. Not all of it is going to be pre-stretched and perfect for the life of the deck, but it's all going to be better than what you used.

    I'm not trying to be rude/snarky, but I don't see this as a code problem. This is a choice-of-material problem. That that happens every now and then is no reason to add more nonsense to the already-bloated code.
     
  12. Mark K

    Mark K Platinum Member

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    I suspect that the problem is not with the cables but with the structure that the cables pull on. Long term creep of the cables should be small and should decrease over time.

    On the other hand the connection of the wood posts that the cables pull on will continue to creep. You tighten up the cables and it will creep more. It never ends. Steel and concrete structures are less likely to see this problem. If you pulled against a shear wall I would expect the creep to be much less and probably not noticeable.
     
  13. Keystone

    Keystone Registered User

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    I’ve had this concern for the years I’ve been seeing cable railing. Having been on inspections and going back a month or years later it’s obvious the cables or supporting structure stretched/shrunk or moved in some manner raising the red flag in my mind.

    I’ve come to the conclusions “steveray” posted, it’s a snapshot in time.

    If this does weigh on you, you have the option of purchasing test equipment confirming adequate tensioning to document the finding at time of the inspection. Is the equipment worth the cost? Should the onus be on the applicant to provide such an item for our records? Either scenario, many factors go into obtaining accurate tension readings that may be time prohibitive for an inspector.
     
  14. Glenn

    Glenn Corporate Supporter
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    These are my experiences with cable rails.

    1) The stainless steel cables will and do stretch. It takes a few rounds of tightening to get them stable. The newer and higher quality products on the market are designed for easy tightening. They recognize the flaw and design for it.

    2) Homeowners that want cable rails, don't want saggy cable rails. They will get it fixed, most likely. Or maybe they won't. I've been to homes with open diapers full of feces laying on the living room floor in front of TV watchers as they pointed me toward the water heater. We can't help people that won't help themselves. Those people likely don't have cable rails.

    3) I have heard the discussion of not maintaining the 4" rule with cable rails for many, many years. There is not end all universal interpretation from a code standpoint. The code is not written to handle this situation. The required design loads and loading criteria is specific, but simply written. However, to not admit that saggy cable rails offer reduced protection from the hazard of openings is to lie to oneself. Ultimately, this is more of a philosophical question about code administration. At what point does government protection end and personal responsibility begin. More simply, construction vs. maintenance?
     
    #15 Glenn, Jul 3, 2020
    Last edited: Jul 3, 2020
  15. jar546

    jar546 *****istrator

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    I honestly believe that cable railings attached to wood supports is just not a great idea for a residential deck.
     
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  16. tbz

    tbz Silver Member

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    Rick,

    1x19/SS 316 alloy cable in either 1/8" or 3/16" are the staples in the industry and that is a cable that has very limited stretching.

    With the stretching keep happening like you are noting, especially older cables like you are talking about, you are more than likely dealing with 7x7 cables and in 1/8 or 3/16 they keep stretching from what I have seen. Sounds like wrong cable and not so good of a connector mixed together.

    Here is a link to a wood post cable termination I strongly suggest using when you can't pass through the wood post or into the side of a column or building.

    http://eastcoastcablesolutions.com/wp-content/uploads/2019/05/Adjust-A-Body-With-Hanger-Bolt-Tensioner.pdf

    Here is a page of assorted connectors from Ultra-tec that are sold by a distributor in MD,

    https://eastcoastcablesolutions.com/elementor-147/

    In my 30 years of doing cable railings with 1x19 cable, except for green wood decks shrinking, I have never had to go back and re-tension.

    Jobs with 7x7 that Architects mandated we use, we always built in plans for service and we would not use 7x7 less than 3/16" also.

    But from the new information, I would venture the cables and the connectors are both a problem building on each other.
     
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  17. ADAguy

    ADAguy Registered User

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    Mystery solved, a DIY using salvaged material from an unknown source.
     
  18. Darren Emery

    Darren Emery Sawhorse

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    What steveray said. This very specific question quickly expands to the much broader topic of how far (in time, not distance) does our authority go? As construction inspectors, not much, if at all, past the point we issue a C.O., or close the file. My first boss told me many times - we can't write up an expected violation. Same could be said for weak bolted connections of guardrail posts. They hold today, but a year from now, who knows?

    This is one reason I really appreciate the fact that we also have property maintenance and fire inspectors in our division. Three viewpoints to from which to come at an issue; we can usually find a way to do the right thing.
     
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  19. Rick18071

    Rick18071 Sawhorse

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    So how often your property maintenance inspectors go onto each residential deck to check the railings?
     

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