EMT will meet code but IMO has no place outside on a roof, the weather conditions in MA make EMT rust out and fall apart (especially in the small sizes) long before the equipment you feed with it. If it gets kicked around on the roof the compression couplings sometimes fall apart.
Try IMC, it sounds like you will be running 1/2" so a 3/4" EMT bender will bend it easily, if you do not have a threader, with some planning you can use very few compression connectors.
Here is a link to some nice supports instead of wood.
http://www.erico.com/erico_public/general_info/pipepiermore.asp Also if you do run PVC, 1/2" 3/4" and 1" need support every 3 feet, 2002 NEC 352.30(B)
Bob
[This message has been edited by iwire (edited 03-07-2003).]
