After the Second World War there was a shortage of skilled labour and materials and this led to industrialised building methods being introduced. At Blackbird Leys, for example, some of the houses were built on site of non traditional materials, in this case concrete not bricks. However these 'Easiform' houses were given pebbledash finishes or had brick front elevations, so that they looked like a traditional house. 'Easiform', was the construction method used for the most innovative buildings on the estate: the two tower blocks of flats. Other system-built houses on the estate included the 'Minnox', wooden framed prefabricated houses, 'Purpose Built' and 'Keir' houses, all of these again being given a traditional finish.