Q.: A dairy farmer has installed some steel-troweled 20- by 90-foot runners in three stalls of his cattle barn. The cows are slipping on the accumulation of manure and the problem is becoming serious. What is the best way for us to roughen the concrete for him?

A.: Probably the best solution is to scarify the surface. Several concrete scarifying machines are available commercially. An alternative is to coat the concrete surface with epoxy and scatter emery over the epoxy before it hardens. This alternative seems likely to be more expensive and perhaps less effective than the first.