blade 11 is clamped to the underside of an exciter mechanism 12 which includes an eccentric device driven by an engine 13 to impart a horizontal vibratory motion to the blade 11 a supporting frame 14 is attached to the exciter mechanism 12 and includes an operator handle 15 the screed 10 is operated over the surface of freshly poured concrete by the operator pulling the blade from the operator handle 15 the vibration isolation system of the present invention is intended to overcome the problems in prior art devices discussed briefly above while providing necessary isolation of vibratory force to the operator these problems include control of the tendency of the blade to move upwardly when the build up of concrete behind the blade is uneven and the need to pull one end of the blade in a circular arc around the opposite end as for movement around a curve both of these operations require a large amount of force to be exerted by the operator and if the vibration isolation device between the operator handle and the exciter is too soft control becomes difficult on the other hand if the vibration isolating device is too hard then the vibratory forces transmitted to the operator become too great the blade 11 is demountably attached to the bottom of the exciter mechanism 12 such that the working face 16 of the blade faces the operator grasping the handles 15 whereby the screed is pulled over the surface of the freshly poured concrete as best seen in fig1 and 3 the upper edge of the working face 16 of the blade 11 is provided with a horizontal mounting rib 17 that is received in a groove 18 in a casting that comprises a lower exciter housing 20 the front of.