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  1. #1
    Join Date
    Jun 2004
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    Georgia
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    Default hurricane straps at hips

    I'm working on a hip roof where Simpson LSTA21 straps have been specified to attach hip jacks to hips. The engineer says to install them on the upper edges of the jacks and fold them over the hips.

    The problem is that with the straps installed, I can't gun nail the roof sheathing to the jack ends. Does anybody know of an alternative, equally strong mechanical way to attach jacks to hips? The hips are single-ply (nonstructural), by the way. I should also mention that there is a cathedral ceiling below.
    Last edited by charles; 05-05-2005 at 06:38 PM.

  2. #2
    Join Date
    Jun 2004
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    Caldwell, NJ
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    3,153

    Default Re: hurricane straps at hips

    Quote Originally Posted by charles
    I'm working on a hip roof where Simpson LSTA21 straps have been specified to attach hip jacks to hips. The engineer says to install them on the upper edges of the jacks and fold them over the hips.

    The problem is that with the straps installed, I can't gun nail the roof sheathing to the jack ends. Does anybody know of an alternative, equally strong mechanical way to attach jacks to hips? The hips are single-ply (nonstructural), by the way. I should also mention that there is a cathedral ceiling below.
    Can't help you with the straps because I've never used any straps for hip jacks before but if the Engineer has it specked then you have to use them or ask him what else you can use because you can't just change what's specked.

    What does this mean by the way? 'The hips are single-ply (nonstructural), by the way."

    What are you using for hips??

  3. #3
    Join Date
    Aug 2004
    Location
    Avon CO
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    156

    Default Re: hurricane straps at hips

    The engineers here usually spec out Lssu hanger for the hipjack connection. With the strap on the top I would sister short 2 x4 to the top side of the rafter to give ply naiing.

  4. #4
    Join Date
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    Georgia
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    Default Re: hurricane straps at hips

    Guys, when I say the hips are single ply nonstructural, I mean that the jacks support the hips, not that the hips support the jacks. Thus it makes no sense to "hang" the jacks from the hips.

    Come on engineers, speak up! There's gotta be a way to bolt the opposing jacks together through the hips.

  5. #5
    Join Date
    Jun 2004
    Location
    Coachella Valley (Palm Springs CA area)
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    290

    Default Re: hurricane straps at hips

    a detail I've had to do before was block the bay on the other side of the hip in line with the jack so after sheathing a strap could be nailed along the top of the jack, over the hip and into the blocking so you end up with a criss-crossing of straps. totally crazy but its what the engineer specked (so cal about 5 miles from san andres fault)we use simpson cs16 and go thru about 200 ft per 7,000 sq ft house on average

  6. #6
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    Jun 2004
    Location
    North Carolina
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    450

    Default Re: hurricane straps at hips

    Engineer here!
    You might check into Simpson U or HUTF. YOu will need to special order these and check with the factory for this particular application. Catalog doesn't provide much detail on these hangers.

    glenn

  7. #7
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    Jun 2004
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    Coachella Valley (Palm Springs CA area)
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    290

    Default Re: hurricane straps at hips

    the minimum header or ledger size for a htuf is 3 1/2 inches so I dont think that will work for Charles.

  8. #8
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    Georgia
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    Default Re: hurricane straps at hips

    rustynail, I like your idea. But I like the idea of a bolted connection even better.

    Glenn, when jacks meet at right angles, is there a standard way that engineers like to bolt them together? For example, would I be able to put a 45 degree wedge of wood on each hip jack end to gain parallel surfaces, and then bolt through the wedges?

  9. #9
    Join Date
    Jun 2004
    Location
    North Carolina
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    450

    Default Re: hurricane straps at hips

    Charles:
    That's a tough question. I've never bolted a hip jack. but here are some thoughts:

    You could probably put the bolts through the point where the jacks are at their full thickness, assuming they line up on both side (which they wouldn't if the ends were a different pitch than the front and back which is becoming more popular). Use a washer and don't be concerned about the angle at the nut and bolt head. (If I were going to use a connector, I'd probably use something like an A35 or an L90 thought the purest would probably nail me for saying that.)

    If you bolted along that line, I don't know why you would need anything, but the bolts should be precisely placed along that line.

    A wedge may be too short and too thin not to split.

    A special fabrication would be too costly and overkill.

    A short jack has very little load on it that three face nails could handle. This would include all jacks less than about 12 feet which should be most of them.

    I'm not sure they are necessary unless someone is arbitrarily requireing them which may be why Simpson doesn't make anything specifically for that.

    What are you required to do with overbuilt shed dormers and intersecting gables? We don't put anything there either. They typically nail down a plate to the underroof and nail the rafters to that here in our 130 mph wind zone.

    I think the hips should be strapped but Simpson makes some nice fasterners for that.

    I'm thinking you would not generally need to strap hip jacks (I don't know about earth quake issues but if the hips and ridges are fastened well together, I don't see a reason to get concerned about it. The sheathing is nailed to the hip as well.)

    I think I could make a good arguament that 3-16d will suffice.

    Good question , maybe someone else can help.

    glenn

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