# Trap door



## Claire001 (Mar 10, 2009)

We want to install a trap door in our high school stage floor. We have 39 inches under the stage, so the door has plenty of clearance to drop down, but I've had suggestions for a door that pulls up or one that pulls completely out like a plug. Advice? Cautions? Thanks.


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## DaveySimps (Mar 10, 2009)

39" is not a whole lot of room to deal with. The type of door you use ultimately depends on what you intend to do with the trap opening and trap room. I have always been a fan of removable plugs. You can alway build a show specific door with a hinge if it is appropriate.

Be very cautious when blocking or rehearsing with the trap open. It can be very dangerous, especially when used with common effects typically associated with them, such as fog and low light conditions.

I would suggest having the actual work done, as opposed to doing it yourself, unless you are absolutely certain of what you are doing. To do this successfully, it goes far beyond simply cutting a hole in the floor and putting in a door. Proper support must be maintained, and locking mechanisms should be used to secure the door when not in the open position. That is just my $0.02.

~Dave


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## dvsDave (Mar 11, 2009)

Good morning Claire!

A trapdoor being installed into your main stage would require hiring a structural engineer to come out and see what needs to be done. How do you intend to make sure the stage around the trapdoor can still support the weight? Most stages floors are a tongue and groove install that gets its strength from the tight interlock with the individual pieces. 

It's far more complex than just cutting a hole and adding a hinge. You have to make sure that when it's not being used, that it can support the weight that it used to be able to support.

That's a pretty vast simplification of some of the issue surrounding a modification of this magnitude. ControlBooth's first rule that overrides all others is safety. If it can't be done safely and to code, don't do it. An injury stemming from trapdoors have the potential to be quite serious.

David


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## Van (Mar 11, 2009)

Claire, I have to wholeheartedly agree with Dave here < both of them>. Making a trap in the floor can be simple AND dangerous. As Davey said it looks as though you have the room for it, As Dave said, this is really work for a structural person. Depending on the size of the trap < area > you may or my no need to cut through joists. As soon as you do this you are destroying the structural integrity of your stage, and endangering anyone on it. The Trap cover, as well needs to be properly engineered; what if someone is rolling a piano across stage and hit the trap cover that's made out of floorboards and 3/4" ply ? Disaster!
I would highly/strongly suggest going to a facilities person at your school and inquiring into how to go about the process of getting pros in help design and them implement the design of a trap system. 
I know it may seem like a silly thing to be this cautious about, but believe me as a individual who has worked on both sides of the theatre world < building them and building IN them> You want a professionally designed and engineered solution for this. 
Now if you were purely talking about wanting to build a trap into a scenic element like a platform that is raised 39" above the stage floor, that is a completely different and much easier subject as it is a temporary structure, and much easier to control the use of. 

Hope that helps.


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## gafftaper (Mar 11, 2009)

As has been said, I would contact the appropriate pros and ask them to help make the cut and design and build a plug for it. When they are gone, on a show by show basis, you can pull the plug out and use it as a model to build whatever you need to go in that hole for a show. Also remember that schools and school districts don't like people cutting up their buildings without permission so make sure you go through official routes with the administration to get permission. 

As long as you are going to the trouble to have someone engineer a trap and build a plug, have 2 or 3 put in. It won't cost that much more and could be very useful to have that flexibility. How about a trap backstage somewhere to give the person a way to get in/out off stage? 

No matter where the trap is, downward opening traps are much more difficult to build strong and safe than upward opening traps so I advise you to try to do the effect you want with an upward opening trap.


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