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Author Topic: Mount 12" box truss to confer block wall  (Read 1736 times)

Nathan Riddle

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Mount 12" box truss to confer block wall
« on: October 13, 2017, 11:52:59 am »

Church asked about hanging some truss on a cinder block wall on their stage.

They didn't want a bid on the project (trying to do it themselves).

I said okay, just figure out what parts you want to use and send them to me and I'll okay them or not.

Well they didn't, they bought this instead without consulting me. It's a mount for a TV. My assumption is they think they can use tapcons to mount the tv mounts to the wall and then put the truss on it.

https://m.markertek.com/product/per-dsf290/peerless-av-dsf290-truss-mount-for-12-inch-truss-with-2-inch-outer-diameter-tubing

https://www.markertek.com/product/per-dsf290/peerless-av-dsf290-truss-mount-for-12-inch-truss-with-2-inch-outer-diameter-tubing?utm_referrer=direct%2Fnot%20provided


I'm inclined to think that isn't designed for overhead lifting even if the weight is below the capacity. Probably has a 1:3 safety factor?

I'm also very weary of the torque that a light fixture can place on the truss and thus the mount and the way it is designed it won't fully clamp around the truss to 'hold it in place.'

I'm leaning on the side of advising them not to use it. Before I tell them not to do that, am I correct?

Also, what is a good alternative?
« Last Edit: October 13, 2017, 12:32:14 pm by Nathan Riddle »
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TJ (Tom) Cornish

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Re: Mount 12" box truss to confer block wall
« Reply #1 on: October 13, 2017, 12:03:04 pm »

Church asked about hanging some truss on a cinder block wall on their stage.

They didn't want a bid on the project (trying to do it themselves).

I said okay, just figure out what parts you want to use and send them to me and I'll okay them or not.

Well they didn't, they bought this instead without consulting me. It's a mount for a TV. My assumption is they think they can use tapcons to mount the tv mounts to the wall and then put the truss on it.

https://m.markertek.com/product/per-dsf290/peerless-av-dsf290-truss-mount-for-12-inch-truss-with-2-inch-outer-diameter-tubing

I'm inclined to think that isn't designed for overhead lifting even if the weight is below the capacity. Probably has a 1:3 safety factor?

I'm also very weary of the torque that a light fixture can place on the truss and thus the mount and the way it is designed it won't fully clamp around the truss to 'hold it in place.'

I'm leaning on the side of advising them not to use it. Before I tell them not to do that, am I correct?

Also, what is a good alternative?
Your link appears to be dead.

If it were me, I wouldn't touch this with a 10' pole.  Attaching to a permanent structure requires structural engineering consultation if it's not a standard way to do something.  I can't imagine any circumstance where a TV mount could safely be used to lift even an empty stick of truss, not to mention the torque from cantilevering.

Run away!
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g'bye, Dick Rees

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Re: Mount 12" box truss to confer block wall
« Reply #2 on: October 13, 2017, 12:17:51 pm »

Show them this and ask them if they think it's a good idea to cut corners when installing a potentially lethal weight above their heads.

https://youtu.be/Iq_Tii5LD8c
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Erik Jerde

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Re: Mount 12" box truss to confer block wall
« Reply #3 on: October 13, 2017, 12:33:21 pm »

Your link appears to be dead.

If it were me, I wouldn't touch this with a 10' pole.  Attaching to a permanent structure requires structural engineering consultation if it's not a standard way to do something.  I can't imagine any circumstance where a TV mount could safely be used to lift even an empty stick of truss, not to mention the torque from cantilevering.

Run away!

Not dead, just a really slow load.  Anyways, the mount they picked is for mounting a TV to 12" truss.  It's not for mounting 12" truss to a wall.  There are ways to do this safely but they take some engineering knowledge.  Anyone who thinks this TV mount is appropriate isn't qualified to design and install a proper support.
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Nathan Riddle

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Re: Mount 12" box truss to confer block wall
« Reply #4 on: October 13, 2017, 12:37:20 pm »

I think it didn't work because I used a mobile link. I edited my original post with a desktop link.

Those were my thoughts as well.
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Keith Broughton

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Re: Mount 12" box truss to confer block wall
« Reply #5 on: October 13, 2017, 01:50:27 pm »

Back away and stay away!!
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Mark Cadwallader

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Re: Mount 12" box truss to confer block wall
« Reply #6 on: October 13, 2017, 01:50:56 pm »

Not even if installed "upside down."  I'm not an engineer, but even I can see that those things are designed to have the weight hanging down, not holding something up. Yikes!
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Stu McDoniel

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Re: Mount 12" box truss to confer block wall
« Reply #7 on: October 13, 2017, 07:57:01 pm »

Show them this and ask them if they think it's a good idea to cut corners when installing a potentially lethal weight above their heads.

https://youtu.be/Iq_Tii5LD8c
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Nathan Riddle

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Re: Mount 12" box truss to confer block wall
« Reply #8 on: October 14, 2017, 07:07:41 pm »

If it were me, I wouldn't touch this with a 10' pole.  Attaching to a permanent structure requires structural engineering consultation if it's not a standard way to do something.  I can't imagine any circumstance where a TV mount could safely be used to lift even an empty stick of truss, not to mention the torque from cantilevering.

Run away!


Back away and stay away!!

So I agree with y'all from a liability standpoint of not doing it.

What about when they're going to do it with or without me?

Cheeseburger's into the concrete with lags will be very strong. Then safety into the building steel above. They're not putting more than 100lbs on the truss.
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TJ (Tom) Cornish

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Re: Mount 12" box truss to confer block wall
« Reply #9 on: October 14, 2017, 08:52:52 pm »

So I agree with y'all from a liability standpoint of not doing it.

What about when they're going to do it with or without me?
Then they do it without you and you have no part in it.
Cheeseburger's into the concrete with lags will be very strong. Then safety into the building steel above. They're not putting more than 100lbs on the truss.
How do you know that will never change?  "Cool - look at this cool truss thing!  We can have our youth group pull up competition on this thing!"
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