by MarkJ » Wed 13 Jan 2010, 11:25:23
$this->bbcode_second_pass_quote('mcgowanjm', 'T')he 1 problem: Because of faulty ductwork, many schools have had to close due to busted pipes in the ceiling. OZ of prevention...

Most commercial work is performed by well paid higher skilled sheet metal workers and installers.
Much of the residential work uses pre-fab ductwork, pre-fab plenums and flex duct, so highly skilled workers aren't necessary.
Almost anyone can be trained to snap ductwork together, hang ductwork, cut holes, install drive-cleat, starting collars, boots, registers and flex duct in a matter of weeks.
The higher skilled guys working on the jobs do most of the more difficult work and custom fabrication, or the fabrication is performed by sheet metal shops, then installed by lower skilled workers.