Berrima Gaol was built over five years with much work done by convicts in irons. Conditions at the gaol were harsh, prisoners spent most of their days in cells and the only light was through a small grate set in the door. In 1866 the gaol was renovated to the standards described by the prison reform movement for a "model prison". However, Berrima gaol had solitary confinement cells which measured 8 feet by 5 feet, some smaller, where it was intended that all prisoners spent one year. In 1877 a royal commission was held to investigate allegations of cruelty by the prison authorities but the complaints were not upheld.