On slope paving jobs, a slope paver, slope slipformer, or hydraulic roller screed can reduce labor requirements, increase production rates, and improve concrete uniformity. A basic slope paver has an adjustable steel-truss frame that spans the concrete slope and rides on wheels on forms or chair-supported pipe rails. By adding hinge-connected frame extensions to the basic paver frame, the machine can be configured to pave wider slopes, a slope with a section of invert (half canal), or the full canal in one pass. Extensions are available in various lengths to accommodate spans up to 100 feet or more. Frame support legs adjust to accommodate different slope angles. Some slipform pavers typically used for road work can be modified by their manufacturers for slope or canal paving applications. For example, one manufacturer has designed a machine frame that can pivot downward to slipform a slope. One track rides on the slope's top edge and the other track rides at the base of the slope. The hydraulic roller screed is designed to screed concrete on slopes as well as flat surfaces. The screed system consists of a roller tube connected by cables to an air winch and rigging bar positioned at the top of the slope. The air winch and cables raise and lower the roller tube on the slope, eliminating the strenuous labor of pulling the tube uphill.