Chalfont St Peter Headhouse

The Chalfont St Peter Headhouse provides emergency services access to the Chiltern tunnel beneath, includes ventilation fans to manage the environment in the tunnel, as well as a series of plant rooms.

Watch on YouTube - Chalfont St Peter Ventilation Shaft

Headhouse construction

We have been working closely with stakeholders to take lorries out of Chalfont St Peter and will create a temporary access road which includes a new signalised junction with the A413 Amersham Road. Noise and air quality monitoring equipment on site will help us adhere to stringent levels. If these are breached, work will have to stop. We are also carrying out regular noise and air quality levels monitoring further away from the site using mobile monitoring equipment to understand the impact of works and how to reduce them even further.

The excavation of the ventilation shaft is now complete.

Slide 1 of 2: An aerial still of the Chalfont St Peter Site.

Slide 2 of 2: View looking up shaft from the base of the Chalfont St Peter ventilation shaft.

Headhouse design

The design of the headhouse has been improved, so the single-story building is now set back from the road and wrapped in a simple grey zinc roof with dark bronze openings. Taking its inspiration from the style of local barns and other agricultural buildings, it is designed to blend into the surrounding landscape. The pre-weathered grey zinc roof will age naturally over time, without loss of robustness or quality, while the whole structure will sit on a simple dark blue brick base.

The landscape design will provide a range of habitats to support biodiversity, created and managed to complement the existing landscape. Mature trees along the existing boundary are being retained as far as possible and, once construction is complete, the whole site will be landscaped with new trees and hedgerows planted to help screen it from neighbouring properties.

To encourage wildlife to return, bird boxes, reptile basking banks, a grass snake laying heap and a hibernaculum will be created. Material excavated from the shaft will be used to create much of the landscaping and avoid putting extra lorries onto local roads. Habitats will be created and managed within the site to reflect the existing ecological character of the Chiltern Hills, including species-rich grassland and a new wetland.