A:Answer Mount the oven against a flat, vertical wall, so it is supported by the wall. The wall should be constructed of minimum 2" x 4" wood studding and 3/8" thick drywall or plaster/lath. Do not mount the microwave oven to an island or peninsula cabinet. Be sure the upper cabinet and rear wall structures can support 150 lbs., plus the weight of any items you place inside the oven or upper cabinet. ^Daphane