Q.: With 1-inch slump concrete topping mixes, it's hard to close the top surface with a bull float. Sprinkling the surface with water helps to close it but also can cause craze cracks. What's a better way to close the surface?
A.: Using a vibrating bull float might bring more mortar to the surface, making it easier to close. If you can't use a vibrating bull float, try putting weights on the bull-float blade to increase the pressure you can apply. Some finishers put concrete blocks or heavy bagged products on the blade to increase pressure. But you must be careful when doing this so the weights don't fall off the blade and mar the finish. Finishing-tool suppliers sell iron or lead weights that are notched so they attach firmly to a bull-float blade.