# Circular Platform



## JohnG (Oct 14, 2010)

So, I am experienced in constructing platforms and building. So today at dinner, I was talking to a coworker. We were talking about triangular platforms, and how they disliked them due to the amount of angles within constructing them. They then said that they are glad that the platforms are not circular, I then said, "wait wouldn't a circular platform be easier to build due to the fact that all one has to do would be to construct a square frame slightly smaller or the same size to match the plywood circle that makes up the top. 
Who is more right?
Which do you think is easier?
Also is that the correct way to build a circular platform.
I am just doing this to get a third parties opinion.


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## MPowers (Oct 14, 2010)

The square in a circle is one way to START a circular platform, but certainly not structurally sufficient as the complete frame. Additional framing will be needed around the edge. Just how much depends on the type and thickness of the material used for the lid or walking surface. If you use a single layer of 3/4" plywood as a lid, 1" over hang is the most you can have before deflection is evident as people walk on and off the edge. 1 1/2" can be acceptable but deflection will be noticeable. There are a number of ways to frame a circular platform but most involve making a number of small triangles on each side to support the large circular over hangs. One very strong but time consuming method is to make a series of 1" wide rings the same od as the circle and stack them up to the desired height. internal framing can be much like you've pictured with additional framing on 24" centers. The face of the exposed rings does not make a smooth surface and must be dealt with. For platforms over 6"-8" inches, the 1" thick frame can have legs attached just like other framed platforming. Another circular frame method is to make a ply ring whose od is about 1 1/2" less that the platform lid, attach it centered to the underside making a 3/4" lip. Now rip 1/4" ply or luan across the grain, into strips 3/4" less than you want the height of the platform to be. Attach the first layer to the ring and then full surface glue and laminate the remaining layers to build up a 3/": thick facing/framing. This is practical for circles about 3' diameter or more and up to about 48" high, although an additional ring must be made for the bottom once the height is more than about 8". 

The main thing about triangles or circles is that internal framing for a platform with a single layer of 3/4" ply needs to be on 24" centers across the grain.

Quick answer with out pictures, but I hope it helps a bit.


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