Hello - I'm planning to have a carpenter fabricate and install some built-in cabinets in my basement (made out of birch plywood, poplar, and regular moulding pieces). The basement currently has carpet over a good quality pad. The carpenter wants to install the cabinets on top of the carpet (but will go along with whatever I request). My concern is that if the basement ever floods (a burst pipe?), I'm going to have a moldy mess of carpet under the cabinets that I won't be able to get out without destroying the cabinets. Should I not be concerned because the cabinets will probably be ruined by water too and will need to be repaired/replaced? If it's better to build directly on the concrete foundation, do I need a vapor barrier between the floor and the cabinets? What do I use for this? Thanks for your advice!

I'm making a 21"x24" frame with 2x4 wood standing on edge. It's going to hold an old ceramic sink weighing 30-50 lbs. What's the best and strongest way to join the 2x4's at 90 deg angles. The 2x4's will be on edge rather than flat. The frame will sit on a base made from 2x4's also. John