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Author Topic: a roof system question  (Read 4323 times)

Bryan Roberts

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a roof system question
« on: August 22, 2004, 03:48:56 pm »

I am doing a travelling festival this fall and have gotten some serious conflicting reports about doing a roof. Last year was a ballast system with 4 crank towers to control the roof. The only problem was it took 3 hours to set up and tear down everything (sound and lights too). Then I did an outdoor show where we used 4 genie stands and put a roof tent over it. We closed the truck door after 1.5 hours.

Although the time save is great, I want to make sure this is not dangerous. Now I understand wind can be a SOB but I would lower the ballast system too if wind hit 40 mph.

SO!! The question is: am i playing with fire if I use the more appealling time saving option of the genie stands with tent roof (no ballasts).

Set up is a 30 x 24 stage with a 30 x 20 roof

Thanks friends!!

bryan
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Bryan Roberts
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Bob Cap

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Re: a roof system question
« Reply #1 on: August 23, 2004, 11:32:04 am »

Bryan,

I have been setting up roofs for many years and am amazed at the number of roof system I see on the net set on Geini Lifts. How do you anchor the roof down?

We used to use scaffolding towers and now use self errecting towers that are guy wired down.

I believe a roof sitting on Geini Lifts would blow away long befor the wind speed hits 40mph!

To be able to pack a roof, sound and lighting in 3.5 hours is a quick load out for me. Read impossible. (Maybe my system is a little larger than yours)?

Take the extra time and keep safty in mind.

Good Luck

Bob Cap
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Bryan Roberts

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Re: a roof system question
« Reply #2 on: August 23, 2004, 04:13:33 pm »

ours is a small set up (30 x 24). the time is what is killing me. I am  curious. Since we have all seen the genie stand roof special, has anyone had experience with this falling over. Or has anyone found and easy to secure it? I was thinking spansets at the top of the genies (3 per side) and then use those ratchet wire thingys (that's professional terminology) to secure each tower down to ground.

Still wondering.

Thanks folks!!

bryan
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Bryan Roberts
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Mac Kerr

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Re: a roof system question
« Reply #3 on: August 23, 2004, 04:13:45 pm »

 Laughing My first reaction to the roof on Genie's with a 40mph wind was that you wouldn't have to lower it, you would be chasing it across the parking lot.

Mac
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Alan Hamilton

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Re: a roof system question
« Reply #4 on: August 23, 2004, 05:16:44 pm »

tallboypro wrote on Sun, 22 August 2004 20:48

I am doing a travelling festival this fall and have gotten some serious conflicting reports about doing a roof. Last year was a ballast system with 4 crank towers to control the roof. The only problem was it took 3 hours to set up and tear down everything (sound and lights too). Then I did an outdoor show where we used 4 genie stands and put a roof tent over it. We closed the truck door after 1.5 hours.


bryan


There are different ways to approach using the genies, and spansets and guy cables can figure into the equation. You want you system guyed no matter how you are doing it.

I'm curious how the genie system is so much faster? That makes me wonder about the other parts of the setup which might concern me more than the use of Genies.

1.5hrs seems too fast to me for any roof system... except an EZUp tent of course Wink



-AlanH
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Bob Cap

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Re: a roof system question
« Reply #5 on: August 23, 2004, 06:49:40 pm »

Bryan,

I'm sorry you seem to think saving a couple of hours is important in this life time.

Let me explaine some of the forces at work here.

When you raise your roof with Geini Lifts you have the first force, gravity, pulling down on the weight. When you get your roof up to your working height you have to make sure it dosen't fly away from the lift of the air moving around it. Hence you would guy wire it down to the ground with two cables at each corner. Now you need to consider how tight you are going to guy these. This adds the force downward of the guy wires.

Since a Geini is only rated at 650 or 800 pounds of lift you will probably over load the lift causing the cables, sheves or shafts to break or collapse.

Now you MIGHT get lucky. Have a really light load. No wind. Easy set-up and load out.

OR.....

You might kill someone!

In reality the guy setting up the real roof, taking all that valuable time probably want to charge you more than the guy with the Geini system......

I hope no one dies from you saving money....

Bob Cap
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Bryan Roberts

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Re: a roof system question
« Reply #6 on: August 23, 2004, 10:35:07 pm »

it's actually got nothing to do with saving money. It is about logistically being able to do the tour. If it takes 3.5 hours to get out a show that drops at 10:30 that means we say good bye at 2 am. If it is more then 6 hours to the next show (and this is a Christian tour so that is happening alot), then we are screwed trying to make an 8 am load in, thus having the 3+ needed hours to get this thing up and started in time. The crew last year killed itself doing it this way and the tour suffered with it.

Now, I am not discounting your wisdom, but so far no one has voiced an experience of this actually turning ugly. Just the possibility of ugly.

On the other hand, I have seen many companies do it the geni lift way and never have a problem.

Are those wire ratchet things called pulleys or what. I know what the spanset is. And the two wires off each tower sounds like the way to secure it.

bryan
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Bryan Roberts
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Bryan Roberts

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Re: a roof system question
« Reply #7 on: August 23, 2004, 10:57:41 pm »

Hey guys
Thanks for the input. I just got off the phone with my boss and told him I will not endorse using the geni stand option on this tour. You are right, safety is no substitute for time saving or money savings.


Thanks again!!

bryan
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Bryan Roberts
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kevin kuptz

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Re: a roof system question
« Reply #8 on: August 25, 2004, 10:33:27 pm »

I recently had to give a deposition for a case where I had provided the stage but another contractor provided the roof - We were both "subcontractors" to the bigger company who had the contract, but was overbooked and couldn't provide the gear. The roof company was too busy to bother with guy wires, even though the roof would be raised to over 25 feet for the show in a n open field between two forests that acted like a wind tunnel. Luckily when the roof came off (and We knew it would) it was at night when it was lowered and it only traveled about 45 feet into the parking lot behind the stage, damaging 6 vehicles parked there. We were lucky that the roof sheared the truss off when it twisted loose and didn't actually hit any of our stuff!
I take all of this seriously, but didn't realize when we left the initial setup that roof supplier wasn't going to tie the roof down! If you think Genie's are OK outside -think about this. This roof was 5 feet above the stage floor in it's "resting" position. What would have happened four hours earlier when there were 5,000 people in front of it and it was higher up in the "wind band"? Never short safety for speed, even if it "seems okay". There is too much at stake - this roofing company, the main contractor and the festival are all now being sued for damages, but things could have been far worse had there been injuries or deaths involved here! I was deposed as a witness, but could have been named in the suit also!






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Brian Ship

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Re: a roof system question
« Reply #9 on: August 25, 2004, 11:37:39 pm »

It's been a lot of years since I have done a tent set up, but it would seem to me that as long as the Geni is not supporting the tent roof that it as a piece of equipment, much a seperate piece of equipment givent the roof is self supporting has little to do with the tent roof if if blows or not away.  Big long stakes drilled into pavement and large ratchet straps, two per post the main detail.

In any case given a misunderstanding on my part that the lighting rig is seperate from the tent roof in general, the GENI lift system of hanging the truss should with legs be sufficient to prevent problems in the wind for a standard rig with or without tent over it.  Granted for a large storm I would tend to lower it, but I just can't see some Geni tower ending up in the parking lot.  

If in question, in the past, I have found that if arranged for, the tent guys are very reasonable in drilling and staking a few holes than tying your tower also down in it's own system of support.

While I have not done such a thing, I expect such a seperate derrived system of roof and truss, much less support for each individually would be sufficient for a storm, much less allow the truss to come down as desired fast without worrying about wet tech people even while doing so.  Asleep on the bus on route while the tent guys worry about the tent roof in the parking lot or what ever the next day.

5 years in doing special events for Chicago - granted as a Carpenter, never saw a tent just blow away.  Could happen but I expect the lighting when seperate has seperate worries than the tent and you no longer have to worry about the ballas6t of a tower in counteracting the wind.

Just a thought.
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Craig Leerman

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Re: a roof system question
« Reply #10 on: August 26, 2004, 05:57:25 pm »

Hi all,

I would have jumped on this topic sooner, but I was trucking a show across the country the last three weeks and have not had daily internet access!

First, a Genie lift is not designed or built for roof loads, just a static balanced load of lighting or a truss. If any problems were to happen, the manufacturer would not be liable, and any insurance would not cover you for any losses or injuries, as you would have used a manufacturers products for a use not intended by the manufacturer.

Also, the standard Genie Lifts is not designed for uploading or side loading, just standard downloads. If any loading whatsoever is applied to the side of a genie, or any sudden uploading (like a gust of wind picking up the roof and lifting the masts in the towers) the Genies can and will fail.

There are many instances of Genie type lift roof and truss failures.

I personally have witnessed 3 roof failures and 2 truss failures with Genie and Genie type lifts.  Most were caused by a sudden change in the weather bringing in high winds. The winds simply either blew over the entire rig, or in one instance lifted the roof off of the masts, and then pulled the rig apart.  After the second lift/roof failure, I instituted a policy of not working on or under that type of roof system. These accidents were what got me into the staging business in the first place.

The third failure I witnesses was caused by overloading the lifts. The contractor had used guy wires to anchor the lifts to some 55gal water barrels for ballast. The roof system was comprised of 12X12 box truss with a tarp on top. Standard 6 can lamp bars were hung across the front and back of the truss roof for lighting. The entire rig probably weighed more than the 4 lifts could carry. As the contractor cranked the rig up, the guy wires exerted more stress on the system and one lift cable failed, causing the lift to retract. The roof system then came crashing down in a heap!  I was working on the indoor stages at the festival, and walked outside  after a coworker told me that the roof looked overloaded. I built the outdoor roofed  stages for that festival after that!  

I also have witnessed two lift failures that just had truss on them. One was from overloading. The lighting contractor was using two Genies to hold up a rear double hung truss 40' long. Because the 40' wide stage was against the back wall, they decided to place the lifts one each side of the stage and pick up the truss from the ends. Unfortunately, the truss was loaded with 60 cans, a bunch of color scrollers, 20 leko specials, 6 big moving mirror intels, and 3 ACL bars. On top of this load was also a rear black curtain.  With all the weight and strain on one side of each of the lifts, the capacity should have been reduced. One lift binded  when they were raising the load. With an uneven strain on the other tower, it started to shift slightly before the guy cranking it could stop. Then it simply started to topple over. Once the rig started moving, it kept up its momentum, and fell downstage, luckily just missing some stagehands, and  my backline.

The other truss failure was when a lighting company used 40' of double hung outside on 2 Genie Super Towers. They blocked the wheels, and put wood under the cranks to level the towers. During the show, a big wind simply blew the whole thing over anyway!

All roof systems have some element of danger to them, but using lifts as part of a roofing system should never be done.

There are two basic ways to ensure that a roof system will not topple over in a wind. The first is to use break away fasteners on the roof tarp that would allow the roof tarp to disconnect and blow in the wind, or tear off in a strong wind, leaving the framework and support intact.

The other basic way is to use a large rig that is sturdy enough and strong enough to stand up to large wing loads.

There is a third type system I designed that basically floated the roof truss and tarp system between large scaffolding towers. The rood was suspended by steel and spansets (with safety chains as a redundant backup)  The concept was that since I did a lot of shows in Maryland and Virginia by the water where its usually windy, I would make the roof "Ride" on the wind when it blew pretty hard (like 40+ MPH gusts)

The concept worked like a charm. The roof was static and just hung there when it was calm. Medium winds would sway the roof slightly, and big gusts or large winds would rock and lift the roof, allowing it to move and dissipate the winds energy.

The only problem was that many entertainers didn't like standing under a moving roof (no matter how over designed) and when a short gusts of wind did lift the roof, it would fall back down on the spansets, steelsets, steel and chains making a large "clunk" sound which unnerved a few performers.   After one season, I switched back to a large rigid scaffolding and roof system (which also Incorporated a break away tarp just for extra measure)  

Craig
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