Yn hanesyddol mae dulliau o gyflawni prosiectau peirianneg sifil wedi golygu contractwr oedd yn cynnal gwaith adeiladu ar brosiect a fyddai eisoes wedi bod yn rhan o nifer o lefelau o ddatblygu’r dyluniad – fel arfer gan ymgynghorydd ar wahân, a fyddai wedi datblygu’r dyluniad drwy’r Broses Statudol cyn penodi y contractwr adeiladu.
Historically civil engineering delivery models involved a contractor engaged to carry out construction work on a project that has already been subject to significant levels of design development – usually by a separate consultant who would have taken the design through the Statutory Process before the build contractor was appointed.