Case study

Treetops Free School

Treetops Free School Net Zero energy in operation building



Department for Education


Grays, Essex

Leading the way: sustainable and future-proofed

Treetops Free School was commissioned by the DfE as part of its MMC1 framework to encourage schools to use modern methods of construction for new buildings. Building for the future, to demonstrate how green and clean the schools of the future will be, Treetops was designed to turn sustainability talk into action – making a real difference to the local community. As such, Treetops is:


Extensively Insulated

Floors, walls and ceilings, built using a structural timber panel solution


Carbon Pathfinder

Compliant with the government’s carbon pathfinder ten-point plan


Powered Electrically

Every system, even down to the Bunsen burners – with zero fossil fuels


Sustainably Sourced

Equipped with highly sustainably sourced materials, such as permeable paving and goat hair carpet tiles


Photovoltaic Panels

Supported by photovoltaic (PV) panels, which will generate approximately 300KW p/a, making the building net zero in operation and reducing the school’s annual energy bills by an estimated £9,000 per year


EPC A+ net zero rated

Designed embracing lean, clean & green technologies, to make maximum energy savings reducing energy demands to achieve net zero in operation

About the project

Offsite construction saves Thurrock Council an estimated £9,000 per year in energy bills

Treetops Free School was developed to offer full-time education, alongside therapeutic behavioural support, for its pupils in Thurrock and surrounding areas with special educational needs (SEN). It also demonstrates how the public sector is leading the way in the decarbonisation of buildings.

Following a year-long build programme, the 3,293m2 school – NZB’s largest school project to date – was the first to reach completion in August 2022 under the government’s new carbon pathfinder scheme, as it welcomed 140 pupils, aged three to sixteen from September 2022.

Increasing capacity for quality education

The concept for Treetops Free School began back in 2016, when Treetops School was experiencing a sustained rise in demand for places, and needed to expand its capacity significantly to keep pace.

The new school design needed to cater for various pupil’s educational, medical and therapeutic needs, which included a sensory room for children and parental spaces for family therapy. All rooms also needed to be incredibly adaptable, so the school could continue to meet different learning needs – both now and in the future. After extensive planning and design work, construction commenced for Treetops Free School in 2021, with Net Zero Buildings working as the lead contractor for the Department for Education (DfE).

We left no stone unturned to lower the carbon footprint of both the construction and operation of this free school – right down to the goat hair carpet tiles.

The timing couldn’t be better. While most schools are dreading their fuel bill this year, Treetops Free School will achieve net zero in operation – significantly helped by the energy generated by its PV panels.

The school is also set up to meet the teaching team’s needs today and to flex to how their needs may change in the future, and the whole building is designed so that it can be easily reconfigured.”

Dan Allison, Director, Net Zero Buildings

Anthony Hattam, Headteacher, Treetops Free School

It is with great excitement that the pupils, staff and parents can now walk through the doors of Treetops Free School. Over the past 18 months, we have seen things slowly take shape, from an area of wasteland to the building we have today. Throughout this time, staff and pupils have been fortunate enough to make site visits and watch the progress of the build, and get to know many of the staff working on the site, I know that the pupils will certainly miss waving to ‘Tyler the Viking’ as they arrive at school every day

Being a part of a ‘Free School’ build, and one that is ‘net zero’ is certainly a once-in-a-career opportunity for many, and something that we feel privileged to be part of. Knowing that the school will not only help the pupils of Thurrock educationally, but also environmentally, is incredibly important to us all.