# New trap door



## Dcdjdrew (Feb 6, 2007)

what is the best method for cuting a small trap That opens UP onto stage (under our stage is hollow except suport braces) 

Thanks

Drew Carson 
Technical Director
Tweet Theatre


----------



## avkid (Feb 6, 2007)

Trace it out, drill a hole in the corner and start cutting with a reciprocating saw.


----------



## Van (Feb 6, 2007)

avkid said:


> Trace it out, drill a hole in the corner and start cutting with a reciprocating saw.


 

Hmmmm Well, No. That's not exactly the advice I'd give.

Find out how you floor is constructed. Unless it is EXTREMELY old it will not simply be a single layered planking job over stud walls. You need to know how thick it is. How you are going to retain the structural integrity of the area surrounding the hole. How you are going to reconstruct the plug so it has structural integrity. Determine the Bevel/Swing of the plug so that it's downstage side can be properly beveled, this depends greatly on the thickness of the floor at the edges and the type/wieght of hinges used for supporting the upstage side.
Personally I'd have a structural engineer look at it first prior to making any major modifications. <believe me not matter how small a trap, this IS a major modification.> 
There are a a ton of things to be considered. If, for example it is a "sprung" floor, or a floating floor, you are going to have two layers of 3/4 - 5/8" ply on the bottom, layed over each other at right angles. then you will have a layer of 1x6 - 1x4 "sleepers" sitting lying on face at 45 degree angles to the top layer of ply. Then you have a layer of 3/4-5/8 and sometimes 1" T&G plywood running up to downstage as the topmost layer then your masonite cover or whatever. 
Now if you didn't understand everything in that last paragraph, don't even attempt the project yourself.


----------



## gafftaper (Feb 6, 2007)

I definitely agree with Van on this one, you are talking about a major project here, not something to be taken lightly or attempted without some professional advice. The actual cutting is no big deal. The question is what kind of damage are you going to do to the integrity of the rest of the stage? How will you plug it up later and make that plug safe? Those aren't easy to answer. I would at least get a carpenter/contractor to take a look at it first, but preferably a real structural engineer.


----------



## avkid (Feb 6, 2007)

If the trap is completely flush with the deck and does not endanger anyone you can leave it in. I would suggest a latch on the bottom that accepts a lock to keep curious actors away.


----------



## Footer (Feb 6, 2007)

Ditto the people I usually ditto. Its much more then you think. Decking systems are built the way they are for a reason, and are VERY expensive to repair. A trap is a great thing to have, but the way you want to build it is not the way to go about it. The best thing to do is to get a 4x4 or a 4x8 hole cut that has a very well built (stress skinned usually) plug that goes in it. You can then build different plugs depending on what you are doing. A well built trap is great to have, a badly built trap can destroy the structural integrity of your entire deck.


----------



## Dcdjdrew (Feb 6, 2007)

Van said:


> Hmmmm Well, No. That's not exactly the advice I'd give.
> Find out how you floor is constructed. Unless it is EXTREMELY old it will not simply be a single layered planking job over stud walls. You need to know how thick it is. How you are going to retain the structural integrity of the area surrounding the hole. How you are going to reconstruct the plug so it has structural integrity. Determine the Bevel/Swing of the plug so that it's downstage side can be properly beveled, this depends greatly on the thickness of the floor at the edges and the type/wieght of hinges used for supporting the upstage side.
> Personally I'd have a structural engineer look at it first prior to making any major modifications. <believe me not matter how small a trap, this IS a major modification.>
> There are a a ton of things to be considered. If, for example it is a "sprung" floor, or a floating floor, you are going to have two layers of 3/4 - 5/8" ply on the bottom, layed over each other at right angles. then you will have a layer of 1x6 - 1x4 "sleepers" sitting lying on face at 45 degree angles to the top layer of ply. Then you have a layer of 3/4-5/8 and sometimes 1" T&G plywood running up to downstage as the topmost layer then your masonite cover or whatever.
> Now if you didn't understand everything in that last paragraph, don't even attempt the project yourself.



I understand what you are saying; but we have a very interesting space, originally we had a much smaller stage that was oak sprung floor then 3-4 years ago we expanded the stage outward basically we built many platforms that were screwed together and to the original edge of the stage and then the entire thing was covered in masonite.” , so I do know how it is constructed. Also the stage is only 2’ tall and if you take one of the front or side masonite covers off you can crawl underneath. Basically all I need to do is to have a door that opens upward so that an actor can pop there head out and close the cover behind them almost like an access panel, this is not a full trap just an access panel. 

Drew Carson
Technical Director 
Tweet Theatre


----------



## Van (Feb 6, 2007)

And this trap is to be constructed in the newly < or semi-newly> "platformed" area of the stage ?? Just getting a clear picture here.


----------



## Dcdjdrew (Feb 7, 2007)

yes it is going to be on the "new" part of the stage.


----------



## gafftaper (Feb 8, 2007)

Well that's different. You are essentially dealing with the same sort of situation that Footer was describing. The problem with the real stage is that (like Van said) you probably have tongue and groove and the whole floor is really interlocking and designed so that everything helps to support the space around it. In a series of raised platforms bolted together, that isn't the case as each section is designed to support itself. I would go back in under your stage and redesign the way the platform you want to up the trap into is supported so that it can be easily replaced. Then you just build a new platform that is you trap platform and swap it in and out as needed. 
As far as the trapdoor here are a few suggestions. I would use 3/4 plywood or thicker. Make sure you cut a good straight square hole. A bevel cut will help the trap fit together smoothly without a large gap in the wood. Assuming you want it to open up, reinforce all the way around underneath with 2X4 so that the trap sits on the 2X4... taking the strain off the hinges. You'll want to use small hinges to make it easier to hide the trap, but if you use too small you can break the hinges when someone walks on the closed trap (I've done that). If you countersink the hinges with a router and do a good spackle job you can hide 95% of the hinges. Choose your hinges carefully so you don't have a large bump in your deck. When the show is over you can replace the platform or for a quick "lock" in your trap just run a couple screws through the trap into the 2X4s below and your trap is secure.


----------

