Watch video interview here.

In Chestnut Hill, Philadelphia, where many sidewalks become buckled or broken because of large tree roots , Bill Hackett of Husky Masonry, Perkiomenville, PA sawcuts a seam in old sidewalk blocks that he is preparing to replace with "3/4 inch two bit" concrete aggregate. This modern blend is preferable to mixtures with round stones or cinders used in earlier times because they tended to break up more easily. To give the newly laid concrete an aged look so it blends in with the older adjoining sidewalk blocks, he sprinkles powdered dirt, which he has taken the extra measure of sifting more finely, onto the newly poured concrete. The biggest challenge of the work, Hackett jokes, is not getting hit by cars.