'Dollhouse' cabin - sanity check

Uncle Dirtnap

Active Member
Hello all! First time posting, but I've been enjoying your collective wisdom for awhile now.

I was hoping for your thoughts on my plan. My daughter's school is doing a version of Cinderella that has lots of quick changes, mostly between the woods with cabin in the back, and inside the cabin. I was thinking of something like a opening dollhouse - a wagon with 2 long side wagons. I've done a quick mock up of what I am thinking:
Closed:
upload_2017-2-7_15-54-3.png

and opened
upload_2017-2-7_15-53-32.png


Scene changes should be pretty fast with a large crew - undo the brakes, move it to center stage, rotate, drop the brakes on the middle, swing out arms, brake. With some practice I think it should be fairly smooth.
I'm imaging some more 45 reinforcements built into the side as faux bookcases, fireplace, etc. Everything would have to be insanely light - foam, etc.

Any immediate concerns? I was considering making the 2 outside ends meet and connect when 'closed', which should add to the stability when the whole structure is moving...

Thanks for your input!

-rj
 
Except for small props, don't use foam. Foam is a significant fire hazard and if it catches fire produces thick clouds of toxic smoke.

I would frame this out of 1x4 or 2x2's with either 1/4" ply or luaun sheets to face it on front and back.

The more you flatten the entire unit out, the more prone it will be to falling over, particularly if this is on wheels. I would also be careful not to make the simulated roof pieces too large or out of a dense material. That will be your primary source of this being top-heavy and unstable.

As for the joints between the wings and the central piece, I'd go with loose pin hinges.

Something to think about the on the porch area. If no one has to stand on it, you don't need wagon brakes which are often a pain to work with and can be difficult to hide on a unit that presents from both sides. It may (or mar not) be easier to go with loose props instead of making the porch part of the entire wagon unit.
 
Ah, that makes sense. I think I gave it a porch just for some theoretical stability, along with a smooth transition to knocking/entering the door. This is just past the scribbling on a pad of paper phase-

Darn foam and it's flammability- I've been doing a haunted house, and the fire marshall had completely different requirements. I just doused everything in fireproofing and he was happy. It's brilliant for bookcases that weigh 10 ounces. I'll need find some new ways to be light -

wagon brakes were the easiest things I could think off -ideally, we would retract the casters and let it settle down, but hydraulics are a little outside the high school budget for a 3 day run. I'll check for easy mechanical castor/lift systems.

I could easily go wider on the ends for stability - there are enough props I can hide the support behind.

thanks for your input!!!!
 
The prohibitions against foam in many building and fire codes are certainly among the most un-enforced regulations. That didn't even change after the Station nightclub fire, where the foam on the ceiling was a significant contributor to the large loss of life.

It will, I'm afraid, require a large loss of life fire on a stage filled with foam scenery - most likely a high school - before things change. There needs to be some changes that add clarity, that permit foam in certain smalle quantities and some situations as well as some active enforcement against the overuse - where there are entire houses built of foam.

Some covering - like muslin and goop (glue, joint compound, fire retardant, etc.) - is in fact pretty effective.
 
Foam is not the only material that gets overlooked or given too much benefit. As we see above, a local fire marshal thought it was fine to spray flame retardant onto foam, even though it has some - but not enough - effect on the flammability.

If you can keep away from foam of nearly all types (hard and soft) and include foamcore in that list, you'll be fine. However, as Bill pointed out, there are ways to treat foam, if you really have to use it, though the additional effort may not be worth it for extra cost and time.

Some things to take into account with foam: it's very flammable and has a low ignition temperature. Once it starts burning it doesn't really self-extinguish. You're only real option is to create a thermal barrier. You're best bet is a good intumescent paint that is laid on very thick. Sherwin-Williams is best, Benjamin Moore is very good. There are others out there as well. Other options are Bill's goop recipe above or variations of it.

You'll want to make sure that you put the coating on thick enough that it can absorb and disperse heat without passing too much through to the foam, maintain it's structure after it's dry, and yet have some flexibility. What commonly happens is that a too-thin coating will allow the heat to pass through to the foam, causing it to melt away from the surface. This creates a cavity under the thermal barrier, which then collapses. The collapse exposes a hole in the thermal barrier and the foam is exposed to flame and it catches fire.
 
Every time something that large has to swing various issues show up. Hinge stress and balance have been mentioned, but clear space, caster issues and who knows what all regularly make a nice concept impractical. Perhaps just having the side panels carried out as needed?

I've had luck with slide out designs if there is something solid handy.
 

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