Using a puddling stick to consolidate grout is no longer acceptable in most building codes. Changing codes now require that grout pours greater than 12 inches be both consolidated and reconsolidated by mechanical vibration. Grout vibrators achieve their vibratory motion by means of an eccentric in the head. The head is connected by a flexible shaft to a power source. The head, shaft, and power source are the three main components of a grout vibrator. POWER SOURCE Most grout vibrators are powered by a gasoline engine or electric motor. Electric vibrators have an advantage in that they are compact, lightweight, and require little maintenance. Vibrators powered by gasoline engines are ideal for projects where electricity is not available. SHAFT LENGTH The shaft transfers power from the engine or motor to the head. To determine the best shaft length for a job, first determine the height of the lift. Add to this 1 foot for succeeding lifts. Finally add 4 feet so that the vibrator operator will be able to work comfortably from a standing position. HEAD DIAMETER The diameter of the head must be small enough to fit into the limited space found in the cores of masonry units and in the restricted spaces in cavity walls. DESIGN CONSIDERATIONS A grout vibrator should be rugged in design so that it can withstand rough handling. To provide satisfactory economic life, all of a vibrator's external parts should be able to stand up to the caustic effects of jobsite chemicals without deteriorating or suffering other damage.