One of the oldest windmills in the UK is at risk of collapse, we are working to save it.

Bourn Windmill is located between the villages of Bourn and Caxton, just south of Cambourne. It was purchased by our charity in 1936 and restored from a state of dereliction into working order.

Watch the video below to learn more about the Bourn Windmill project with Graham, one of our Mill volunteers. 


The Windmill dates from before 1636. It is an open trestle post mill, which means that the whole mill rotates around a central pole. There are only around 50 of this type of extraordinary windmill remaining in the UK, 5 of which are in Cambridgeshire. Much of the mills' interior and workings are original with numerous names and dates carved onto the woodwork. In recognition of its heritage value to the nation, the windmill is designated as an Ancient Monument and is Grade I listed.

Graham Bruce is one of the Cambridge Past, Present & Future volunteers who helps to maintain the mill, “during a routine inspection in 2020 we found evidence of rot in the cross beams. It is the beams that help support the weight of the mill and so this was a bit of a concern, so the charity contacted Historic England for help. They provided advice and an emergency grant to pay for a structural engineer and Millwright to carry out investigative surveys.”

In June 2020, they started removing the bitumen that protects the woodwork in order to assess the extent of the rot. What they found surprised and concerned them, as Bill Griffith’s, the Millwright describes “a sand and cement type material, which we had imagined had been used only in a limited way as a filler for small defects, was actually extensively distributed in the centre of all four crosstree arms. The wood surrounding this sand and cement material showed rot in several places and it appeared that rainwater was infiltrating the structure of the crosstree arms". The mortar was used for repairs in the 1980s when rot was discovered. These repairs are now over 35 years old.

The conclusion was a risk that the beam could fail and the mill could collapse. It was considered that it was not safe enough to complete the investigative surveys, which triggered the start of the first major phase of this project.

Phase 1 Preventing collapse and designing repairs

The mill needed to be made safe by scaffolding/propping. Once this was done the surveys to assess the extent of the damage could be completed. The mill was closed until further notice, and has been placed on the “Heritage at Risk Register” by Historic England.

We were delighted to be awarded an emergency grant of £23,250 by Historic England towards the £33,000 costs of the first phase of the project. The remaining £10,000 has been raised from members of the public through a fundraising appeal, as well as some small grants from South Cambridgeshire District Council, Bourn Parish Council, Paxton Parish Council and the Society for the Preservation of Ancient Buildings. The support was amazing - thank you!

This funding has enabled us to tender and appoint an experienced project team, led by Tim Buxbaum. The sails of the mill have been removed (see video below) in order to lessen the weight on the supporting beams and to reduce the impact of the wind. Once this was done the scaffolding and propping was put in place. We were all relieved that this urgent work had been carried out because it meant that the risk of the mill collapsing in a storm has been significantly reduced.

Despite some delays caused by the pandemic the project team was able complete their investigations to understand the full extent of the damage and how to repair it.

The huge beams that support the mill are 140 years old and it was considered that they are beyond repair and need to be replaced. The brick piers that they rest on also need major repair. We also need to repair a rotten window frame, stop a leak in the buck and we would like to renovate the sails before they are re-installed.

Phase 2 Repairing the mill and re-opening it

The estimated cost of repairing the mill is around £170,000. We are incredibly grateful to the National Lottery Heritage Fund and Historic England for providing significant grants to cover most of these costs. We needed to raise another £10,000 to complete the fundraising and we are incredibly grateful to the Pilgrim Trust, Marshall's of Cambridge and many individual donors for their support - Thank you! 

We have appointed Baker's of Danbury as the main contractor and they started work in spring 2022. The main task is to jack up the body of the mill by 6 inches, so that the rotten supporting structures can be disengaged and removed. The brick piers will then be renovated and a new set of huge beams will be cut and slotted into place. Once the team is happy with the new supporting structure then the main body of the mill will be lowered 6 inches and reconnected. If it all goes to plan, we should have completed these works in October 2022. We then need to re-install the sails and do some painting. We would love to be able to have an official re-opening in spring 2023 for the mill to welcome visitors again for the summer season.

Phase 3 Engaging more people with the mill

We recognise that repairing the mill is a great opportunity to engage more people with this fascinating machine and to better tell its story. We are grateful to the Lottery Heritage Fund for providing funds to enable us to carry out a number of projects to achieve this, these will include:

  • Video tour of the mill in conjunction with a local school and mill volunteers.
  • Two self-guided walking routes connecting the mill to Cambourne and local villages. There will also be some guided walks.
  • New interpretation panel at the mill, created in conjunction with local school.
  • Resource for schools about the mill.
  • New visitor information leaflet.
  • Induction guide for mill volunteers.
  • These resources will be made available on this website, meaning that even if you live on the other side of the world you can explore the mill.

We have partnered with CambridgeshireACRE to deliver these projects, which will be completed in spring 2023.

Please contact us if you would like to help or get involved. 

Please continue to follow this page for updates and progress reports on the Save Bourn Windmill project.