News on HS2 in Bucks & Oxfordshire

The final design for the latest of our ‘barn design’ headhouses providing ventilation and emergency access to the 10 mile-long Chiltern tunnel has been revealed . Residents can find out more about the design and construction of the Chalfont St Giles vent shaft and headhouse at a dedicated community online information event on Thursday, February 11 and also on Monday, February 15 .

Set into a fold in the Chiltern Hills near Chalfont St Giles, the headhouse is designed to fit into the surrounding landscape and takes its inspiration from the style of nearby barns and other agricultural buildings. We engaged with the Chilterns AONB Review Group and Buckinghamshire Council during the development of the designs and held a series of public engagement events to gather views from the local community.

Like the nearby headhouse at Chalfont St Peter - which gained planning permission last month - the single-story building will be wrapped in a simple grey zinc roof with doors and vent openings picked out in a dark bronze colour to provide contrast. 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. Below ground level, a 43-metre ventilation shaft will reach down to the twin tunnels below, with fans and other equipment designed to regulate air quality and temperature, remove smoke in the event of a fire and provide access for the emergency services.

Mature trees along the existing boundary will be 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 the site from neighbouring properties. Within the site boundaries, species-rich grassland habitats will be created, designed to further blend the site into the surrounding Chiltern Hills.

Material excavated from the shaft will be used to create much of the landscaping and avoid putting extra lorries onto local roads. A new temporary marshalled lorry holding area has also been established on the A413 near Gerrards Cross where HGVs can be held until their approach to the vent shaft site is clear, helping to reduce congestion and eliminate queueing at the site entrance.

The plans were drawn up by our main works contractor Align JV (Bouygues Travaux Publics, Sir Robert McAlpine, and VolkerFitzpatrick, working with design partners Jacobs and Ingerop-Rendel, the architect Grimshaw and landscape designers, LDA).

In February 2020 we held an event to share our plans for the Chalfont St Giles vent shaft and we are now able to share how your feedback has been incorporated into the design at our 'You Said, We Did' online engagement events.

Due to COVID-19 we are not currently able to hold face-to-face public events, but we are holding these online events to update you on the design of the Chalfont St Giles ventilation shaft and to also provide an update about our construction works at the Chalfont St Peter vent shaft. These online "webinars" have been set up to give the local community the opportunity to hear from the team designing and building the railway in your area.

During the sessions we will discuss:

Our team of experts will also be available to answer any questions you may have during the event.

This event is being held on two dates, please select which date to you would like to attend when registering:

If you have a question about HS2 or our works, please contact our HS2 Helpdesk team on 08081 434 434 or email hs2enquiries@hs2.org.uk .