No, if the surface is not cleaned and prepared properly, it will look terrible once sealed and the sealing product will fail prematurely. To work properly, all sealing products need to be applied to a clean, properly prepared surface, in order to achieve maximum penetration and adhesion. When there is a layer of dirt on the surface, it creates a barrier between the sealing product and your structure, leading to pealing, flaking, and premature failure. We do the job right, which is why we strongly advise full service to help ensure your satisfaction upon job completion.