One of the oldest windmills in the UK was at risk of collapse, read about our incredible project 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 was 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 was 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 were 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 had 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 were beyond repair and needed to be replaced. The brick piers that they rest on also needed major repair. We also needed to repair a rotten window frame, stop a leak in the buck and  renovate the sails before they were re-installed.

Phase 2 Repairing the mill and re-opening it

The estimated cost of repairing the mill was 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 SPAB Mills, Pilgrim Trust, Marshall's of Cambridge and many individual donors for their support and to Lord Foster for helping us to raise the profile of the project - Thank you! 

Tim Buxbaum and team managed the works and we appointed Bakers of Danbury as the main contractor who started work in spring 2022. The first main task was to jack up the body of the mill by 6 inches, so that the rotten supporting structures could be disengaged and removed. This was the most nerve wracking part of the project because this is something that was last carried out 140 years ago, and not something that many people in the world have experience of! There was much discussion about how to do it, but in the end it all went well. The supporting beams were then removed and we could see for the first time the full extent of the rot - it seemed remarkable that the mill had not fallen over.

At this stage in the project, the mill was suspended in mid-air, held there by metal supports! The next task was for a new set of huge beams to be cut and slotted into place. This work was carried out by a skilled team of carpenters over the summer and completed at the end of September 2022.

The brick piers that support the beams were taken down and the main task for October was rebuilding these. Once the team was happy with the new supporting structures and the brick piers, then the main body of the mill was lowered 6 inches and reconnected. It all went to plan and was completed in November 2022 when the scaffolding was finally taken down too, just in time for the cold weather snap.

The sails were taken down so that the millwright can restore and repair them. They are much bigger and heavier than they appear when on the mill and it took a strong team of volunteers and wardens to move them in January 2023.

Finally, the mill was repainted and the restored sails were re-installed. The mill looked as good as new!

Phase 3 Engaging more people with the mill

We recognised that repairing the mill is a great opportunity to engage more people as visitors and volunteers with this fascinating historic machine and to better tell its story. We are grateful to the National Lottery Heritage Fund for providing funds to enable us to carry out a number of projects to achieve this, the included:

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

We partnered with CambridgeshireACRE to deliver these interpretation and community engagement projects, which were completed by summer 2023. 

Cambridge Past, Present & Future couldn’t have done this amazing project without everyone who donated to the campaign to save the mill, all the mill volunteers and to our funders National Lottery Heritage Fund, Historic England, SPAB and The Pilgrim Trust. Thank you very much!

Please contact us if you would like to help or get involved or donate to support our work to care for and share heritage in Cambridge.