Johnston C.P. School caters for 210 full-time pupils as well as providing nursery facilities and a Learning Resource Centre (LRC) which will cater for up to 20 children with complex or additional needs. The build was funded jointly by Pembrokeshire County Council and the Welsh Government under the 21st Century Schools Programme.

The design philosophy behind the building was to provide a spacious, light-filled and naturally ventilated school, with the intention of also reducing the long-term energy consumption of the building.  The building services have been designed to keep energy consumption to a minimum and to provide energy-monitoring facilities for the building users, as well as providing free, ‘green’ electricity for the running of the school via the photovoltaics. This included double and triple glazed windows across the school.