My garage (in a 1950 wood frame house), is constructed of three 10' high cinderblock walls. Over it is a second floor bedroom, and behind it is my kitchen. The two long side walls are bearing walls, but the rear wall is not. I'd like to cut the rear wall down by about 6' so that I can expand my kitchen into the end of the garage. Do I have to worry that the side walls could bow out or anything like that if the rear wall is no longer full height? The ceiling joists rest on the side walls, so I guess they give them som additional stability. Any advice would be appreciated.