4'x16' platform - 10' high

[malibu]

Hey guys, 1st post.


On the set design I was just givin for our fall show. The SD wants a 4x16 platform 10' high. Would it work to just do normal double 2x4 legs with a lot of bracing, or is there a better way?


Thanks!

[JChenault]

Originally Posted by malibu

Hey guys, 1st post.

On the set design I was just givin for our fall show. The SD wants a 4x16 platform 10' high. Would it work to just do normal double 2x4 legs with a lot of bracing, or is there a better way?

Thanks!

You will likely have two issues with this. One is the entire platform wiggling when someone walks on it. This can be addressed by lots of cross bracing, (within the 4 x 16 space of the platform). The second issue you should think about is the stability of the entire unit. If I have a perfectly solid platform that is 4 feet wide at the narrowest, and 10 feet tall, it is will be tippy and the whole thing could fall over.

To fix this second problem you need some kind of bracing to make the base wider - in the 4 foot direction. Stairs ( I assume there are some stairs in this - otherwise how could anyone get up there) might provide the diagonal bracing outside of the footprint of the platform. Tieing the unit to a wall or other solid architectural feature will help, as will attaching the feet to the floor. Note that just attaching the feet will probably not be enough for safety. At the very least you will need to tie the feet into the floor, and then run some diagonal bracing from the top of the platform to the floor so that the effective base is closer to 8 or 10 feet wide.

[Footer]

Building this exact thing right now but mine is 21'x4'x10'. It will be up Monday. I will post some pictures to give you some ideas.

[Van]

I think JChenault, covered most of the important parameters. With the proper amount of cross bracing and perhaps a couple of jacks on the US side you should be fine. Depending on the load you could almost get away with 1x4 "hog-trough" for legs. 10' feet is right on the edge of safe "Legging within the foot print" of a platform.

[gafftapegreenia]

I agree with Van, hog-trough legs are a good option. I've seen people get really hardcore and do them out of 2x6.

Whats nice a platform like this is that if you have two stock 4x8 platforms it's partly built already.

Apparently we're going to be building a rather large and tall platform for Midsummer, so I'll be sure to post some info on that process.

Whatever you decide secure crossbracing is a must.

[gafftaper]

I use a stud wall system. See this article for a detailed description with pictures of building both the platforms and the leg units. No reason you couldn't build them 10' high using the same technique. For platforms 8' or higher and narrow (like yours) I would add some jacks to guarantee it won't tip.

[JChenault]

Originally Posted by Van

I think JChenault, covered most of the important parameters. With the proper amount of cross bracing and perhaps a couple of jacks on the US side you should be fine. Depending on the load you could almost get away with 1x4 "hog-trough" for legs. 10' feet is right on the edge of safe "Legging within the foot print" of a platform.

Van
I am assuming by hog trough you mean a u-shaped leg made from three 1x4s. What do you see as the advantage to this over something like a 2x4? How would you attach it to the platform ( my simplified mental image of this is a framed platform with the 2x4 bolted to the frame ). It's not clear to me how you could easily bolt this in.

(or are we talking something other than a framed platform with legs).

John

[gafftapegreenia]

So apparently a hog through is three pieces and a strong back is two pieces?

Gah.

[gafftaper]

Ok, I admit I've never heard of a hog trough and I'm confused what it is used for. More information please! A picture or drawing of one in action would be great.

[sk8rsdad]

I haven't heard it referred to as a hog trough but we use them all the time. Essentially it's a pair of 1 by's joined in a right angle. It gives you the equivalent of dimensional lumber without the weight.

To put a deck on top, frame out the deck with a 1 by frame and rest it on top of the hog trough leg. Tie them together with plates, or another piece of hog trough nested on the inside so that it straddles the deck frame and the leg.

I've attached a quick sketch of a hog trough. I'm short on time for making a sketch of how it connects to a deck frame.