
Amersham Headhouse
Amersham Headhouse and Ventilation Shaft is one of five structures that will be built to provide ventilation and emergency access to Chiltern Tunnel, which is the longest tunnel on the HS2 route. It is set in the middle of a road junction just outside Amersham.
Headhouse construction
Below ground level, the 38-metre-deep ventilation shaft will reach down to the twin tunnels below. Construction of the shaft is well underway, with the excavation complete and the site team moving on to the structural work inside the shaft.
Once construction is complete, new tree planting will be added to frame views of the headhouse and areas will be set aside for chalk grassland to help create valuable new wildlife habitats. The new planting will focus on native species typically found across the Chilterns, such as wild cherry, buckthorn, and crab apple.

Slide 1 of 3: Sunset over the Amersham Ventilation Shaft.

Slide 2 of 3: Birds eye view of the Amersham Ventilation Shaft.

Slide 3 of 3: Looking up the Amersham Ventilation Shaft.
Headhouse design
Building on feedback from Buckinghamshire Council, the new design will see the weathered steel boundary wall replaced by a more traditional stone wall made of flint. The stone is naturally occurring within chalk hills like the Chilterns and flint facades have been a prominent feature of local architecture for hundreds of years.
The new designs will also see the height of the circular single storey building reduced by more than two metres and the ‘crown’ of steel fins replaced with perforated pre-patinated zinc panels to help match the natural tones of the surrounding landscape.
The layout of the buildings will remain unchanged, with the spiral shaped walls echoing the shape of the site and the shaft beneath, while extra planting will be provided on the A413/A404 side of the site.

Slide 1 of 6: Artist's impression of the Amersham Headhouse compound viewed from A404 looking south east.

Slide 2 of 6: Artist's impression of an aerial view of the Amersham Amersham compound.

Slide 3 of 6: Artist's impression of the Amersham Headhouse looking east from Whielden Lane.

Slide 4 of 6: Artist's impression of a view of the Amersham Headhouse looking west from field next to the site.

Slide 5 of 6: Artist's impression of the Amersham Headhouse looking south from A413.

Slide 6 of 6: Artist's impression of the Amersham Headhouse seen from Whielden Lane looking west with additional planting.
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Archaeology
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Keeping you informed

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Managing impacts of construction
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Construction look ahead
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