[TowerTalk] Tower regulations for home brew towers in the US?

[Markku Oksanen]

All
Just because I am curious:
Here at OH-land even large towers can be home brew just like my 160 and 145 foot rotating towers.These have been made by a private small company that made perhaps 200 towers through the years.Building permit and zoning never questioned the "engineering" of the towers as the responsibility in the end rests with the owner.In addition, home owner insurance happily includes towers and covers damage without question.
How is the situation in the US?  Looks like most towers are commercial (Rohn, couple others) and it seems that a "professional engineer" (correct??) needs to look at the mechanics of the whole thing in order to get a permit to put up a tower.
So, how, if at all, is it possible to build your own large towers?  Does anybody do this?  
The towers I have are 1.5 feet a side with 2 inch tubes, inverted U (0.7 inch) "cross bars".  Only guyed at two levels and full of aluminium, 8000 lb steel guy wires and ball bearing guy rings.  And they have survived some crazy storm too in the past 15 years.
MarkkuOH2RA/OG2A/WW1C