A concrete curb usually serves 4 main purposes: provide a uniform structural limit to the roadway edge, provide constraint and control of storm water drainage within the road way, provide an aesthetic ‘finished’ look, and also to control vehicles from driving on and disturbing the right of way (grasses, sods, sidewalks, plantings, trees, etc) Curbs are typically found in urban and suburban areas and can rarely be found in rural areas except when particularly necessary. There are numerous styles of concrete curb profiles ranging from straight to curb and gutter to slope faced curb. Curb and gutter refers to a monolithic curb used where drainage is planned to be contained along the gutter channel into a drainage structure or other outlet location. Slope faced curb is commonly seen in suburban areas where the curb can be mounted at low speeds and passed over.
Hand formed concrete curb refers to curb formed and placed by hand, in lieu of being machine ‘slip-formed’. Hand forming is more labor and material intensive and thus, when sufficient quantity exists, typically costs more than slip formed curbs. There is typically a stone base specified to be installed prior to the curb placement which provides a smooth, compacted, steady surface for the curbs. Then the wood or metal forms are placed into position, often with steel ‘dee’ stakes, and the concrete is placed, consolidated, and shaped in the forms. At just the right time shortly after placement, when the concrete is self supporting but can still be surface finished, the forms are stripped and the final finishing can be completed. Curbs commonly receive a broom finish and are sprayed with a membrane forming curing compound to help with hydration.