I have an over the range microwave and have only one location to mount it. Unfortunately the wood that makes up the bottom of the cabinet is extremely thin and not strong enough to support the microwave.

My plan was to remove the bottom of the cabinet, install a thicker piece of plywood, make it flush with the bottom of the cabinet and install new support brackets underneath.

Is this a viable plan?

here are images of the location, the bottom of the cabinet and the staples that are attaching the existing shelf to the cabinet.

Edit: i can't figure out how to post the pictures.

 

I doubt that removing the bottom of the cabinet is a good idea.

Generally most wall cabinets will have a face frame, and it creates a recessed cavity on the bottom. If this is the way your cabinets are, I would recommend that you simply cut a piece of 3/4" plywood to fit inside this recessed area, use a few kreg pocket holes on each side, and screw it to the bottom perimeter of your cabinet with a little glue and 1 1/4" pocket screws.

Your microwave should have a metal plate that goes on the wall... This holds the half the weight of the microwave so that its not all on the cabinet bolts.