I just did a small festival this weekend where a homemade stage was provided. The actual stage FLOOR was fine.
However.....
Surprise surprise, TV tower sections were used as "truss".
Needless to say I made sure that no lights or PA were suspended from that.
The roof..... well, first the "truss" for the roof was just laying up there... ie NOT bolted or otherwise connected in any way to anything. A windstorm would have blown the roof clean off. Thankfully there wasn't much wind.
Secondly, there wasn't enough support in the roof between the fact that it wasn't real truss and that the spans too far apart. So the stage builder cut holes in the tarp so that water wouldn't pool up on the roof and collapse it. Guess where these holes were..... RIGHT OVER BACKLINE!
So every time it rained, water was pouring down on the back of the stage in a steady stream.
It poured rain several times and only a very small section of the "covered" stage ended up not getting soaked, thanks to these holes. Fortunately it didn't rain during any actual performances and no major damage happened.
As I have said before, I can usually tolerate a homemade stage, but roofs scare me. People vastly underestimate the danger involved.
