 One of their aims was to help reduce use of concrete and minimise the negative impact of construction on the environment.In 1969, Critchlow formed Polyhedral Developments (a private company) in partnership with architectural designer Hayward Hill; together they pioneered the use of polyhedral domes as emergency shelters for families who had lost their homes to disaster.Critchlow and colleagues experimented in the use of lightweight materials for the construction of domes, including Tri-Wall Pak corrugated board, to aid in transport and assembly by unskilled labour in disaster areas.