I have the arduous task of breaking up approximately 20 square meters of concrete in my back yard - some of which is a foot thick! The yard is walled in with brand-new red brick walls, 7 feet tall. When I break the concrete, i don't want to damage the walls in any way. I was thinking that I should maybe use a saw to cut the concrete, leaving a margin of about 4 inches next to each wall, and then use a breaker from that saw line? But I am not sure. Any recommendations would be greatly appreciated.