"hamzio" wrote in message
...

2x4 sagged in the middle with no support.

Your right about the support. I've built benches that would support a lot of
weight using nothing bigger than 1X's and 3/4 in MDF and plywood but have
used plenty of support, aprox every 18 in. under the top surface. Regardless
of the structure that you choose, I'd skip the pressure treated stuff for
indoor use. They don't recommend it for anything other than out door use
(decks, fences and etc.). You have to use either hot dipped galvanized or
stainless steel fasteners, anything else will rot out the newer pressure
treated stuff. Also some of the chemicals used for treating can be a hazard,
particularly when burned.

Good Luck, Rob Mills