My platform system

[gafftaper]

I've had several people ask me how to build a good quiet platform in the past. I just finished putting one together and built some new pieces. As long as I was doing it I thought I would take a bunch of pictures and post them. So what follows is a step by step guide through the system I use. I'm sure there are lots of other great options out there, but currently this is my favorite. I admit the platforms are very heavy... but they are very strong, very quiet, and very stable. I see no reason you couldn't use this system to build a platform 10 feet tall if you wanted.

For the platform itself I use a 2X4 frame with a brace every 24 inches. The platform pictured is only a 48 inch square but you will see examples of an 8 footer below.

I place a layer of 1/2 inch sound proofing board underneath a layer of 3/4 inch plywood. This is the same fibrous stuff used in walls to keep the noise down between you and your neighbor. It's really nasty stuff to work with so use a respirator if you have to cut it. And be careful how you breathe when you are loading it at the lumber yard.


Think of your platform as a giant drum head. Keeping the platform quiet is all about minimizing vibration. So we use a thick plywood stock, we put a layer of sound deadener in the middle to absorb vibration, and by placing braces every 24 inches which are screwed into from the top we shrink down the area that is free to vibrate.


Now for the legs. Build legs of 1X4 and 2X4 as pictured below. The 2X4's are 24 inches apart... this lines up perfectly with the bracing on the platform to transfer the weight perfectly.


Now cut a cover for every second section. This is to create cross bracing to prevent rocking the long way on the platform down the road. I use 1/4 inch luan. You could also use 1/8 inch luan, or even Masonite. It doesn't have to be thick at all. It's simply fixing the distance on the surrounding 2X4's so they can't rock.


Now bolt together however many platforms you need.


And attach the leg units, 2 per platform. I just use either a 2 or 2 1/2 inch screw through the 1x4 of the leg unit and into the main long 2X4 of the platform. One screw per "square" is enough.


Now attach cross bracing to the legs. Each end gets a straight piece of 1X3 that matches the distance between the legs where they attach to the platform... make sure you've got everything square and plum in this step. Then add diagonal cross bracing every 4 feet. This doesn't have to be particularly strong... I use 1X2 or 1X3. Be sure that your diagonal cross bracing alternates for added strength... always pre-drill your holes when using 1X2 and 1X3, it WILL split.


If you are putting several platforms together be sure all your cross bracing is always high to low, low to high, in every direction there is never two of the same side by side...

That's it, now get an army and roll that bad boy over.
The only problem I have with this system is the occasional squeak of two platforms flexing when an actor walks. Often this can be solved by adding another bolt between platforms or tightening existing bolts. I'm thinking about adding some sort of thin rubber strip between platforms to prevent squeaks. To finish it off I just enclose it with luan facing.
Like I said, it's a serious pain in the butt to move around but it's quiet and strong. I've seen people stuffing platforms with pillows, blankets, even stapling fiberglass insulation underneath. You won't have to do that with this system. If you have the storage space, you can keep all the parts and re-assembly is very rapid. At my old high school over a period of several years I developed a nice stock of several standard heights. I could grab some 16, 24, or 32 inch legs and slap together the perfect platform in no time.

[cutlunch]

Thanks Gafftaper that is a very good presentation. These platforms are definitely built solid. How do you store them stacked flat or verticaly? How much does the timber cost in each platform?

Just out of interest what is the tallest one you have made?

Thanks again for posting this info.

[Charc]

Am I the only one who can't view the pictures?

[soundlight]

Nope, I get a DNS error every time that I click one of the links.

[Logos]

So do I. Can't view them.

[Chaos is Born]

How thick are these platforms when completed? and whats the weight ratio for leg support (how much of the platform can be hung out over something with little to no deflection and no support)?

Our theatre at the school here is working with "Triscuits" Basically a 4'x4' square that you build stud walls to support. They weigh in at about 75-80 lbs a piece but they are solid as a rock and are quiet as well. These are only 2 1/4" thick. You can also hang 2/3rds of them off an edge with no support under those 2/3rds and it will have less than 1/2" deflection. The amount of support per square foot that these can hold is aproximately 200lbs.

If you would like a drawing i can post one up for you guys.

[gafftaper]

Sorry... looks like Yahoo doesn't want that many people to look at my pictures. Here they are below.

I've only built them to 6' high... but clearly it's just a matter of how well you build the "stud wall" supports. I store the platforms in a flat stack and the legs are light enough that they can be stashed in whatever interesting hiding places you can find in your theater.

EDIT... I've attached the pictures to this message redirected the links to control booth so they should work now. (Anyone know why the [IMG] function isn't working? I was hoping to make the pictures appear in the post not as links.)

Chaos: I have to admit I've never done the math and I should. The platform is the design my college T.D. always used in his 40 years of theater. I added the sound board and change the way he did the some of the bracing. I'll tell you this I've seen a lot of dancers on these things and they never budge. I've never put them into a situation where I was worried that they might be over loaded so I've never taken the time to do the math. Our show opens tonight... once I get done with that I'll curl up with my backstage handbook and calculator and figure it out. I bet the platforms weigh around 100 pounds for a 4X8 (we are talking 4 1/2 2X4's, a sheet of 3/4 ply and a sheet of 1/2 inch sound board in each platform)... I can sort of move them on my own but always try to have at least one other person help me. Platforms total 4 3/4 inches thick but that layer of sound board compresses a little when you screw this thing together so it looses 1/16-1/8 of an inch depending on how much you squeeze them.

And please post a sketch or picture of your triscuits. I was hoping to both help those who need a system and to generate some debate at the same time with this thread. We all are looking for a better platform right? I've been very interested in trying some triscuits but haven't done it yet.

[jwl868]

If I ever have the occasion to make platforms again, I hope I remember this thread. I like the leg "system". Looks a lot easier to build (and disassemble for storage and re-use) that the system I've used.


Joe

[gafftaper]

Cost? Well around here a 4X8 platform is currently running about $55 for wood. A 24" high leg unit is currently running about $10.

[Chaos is Born]

Ok, here is a quick rough drawing.

The grain of the plywood runs top to bottom on this drawing (so that the long pieces of 1x are holding the full weight of the grain from the plywood)

You would make studwalls for the legging units, the vertical legs only have to be every 2' though. (can fudge it to 3' for ease if needed)

For strength and multiple useage you would want to use AB ply, and grade A 1x (yes expensive but these are some resiliant platforms)

Sandwich the 1x strips between the 4x8 sheets of plywood using glue (and staples only to hold them in place). The glue is what makes this so extremely structural.

As said before, these weigh about 75-80 lbs and you can easily have half of them with no support overhanging nothingness and up to 3/4 of them if secured correctly.

And these are about as strong as your stage floor and are quiet as well.