The performance of waterstops is to a great degree dependent upon the care and skill with which they are installed. Before beginning, analyze the joint across which the waterstop is to be installed. Choose the shape and size of waterstop that is best suited to the job at hand. A crucially important aspect of waterstop installation is the care with which splices are made. If these splices are made haphazardly, water leakage is sure to be objectionable great. For polyvinylchoride materials, heat to 450 degrees F. a one-fourth inch steel plate on a plumber's torch. Apply the two cut edges of the waterstop to the plate and hold together until they have cooled completely. Rubber waterstops can be cold lap spliced by overlapping the ends of the waterstop and holding it together with bolting. Metal waterstops are spliced by welding. After both portions of the concrete have been cast there remains the application of the joint filler. These protect the waterstop material from the adverse effects of the atmosphere. There are a number of excellent products on the market.