About The Sill

The Sill is an iconic new building that harmoniously reflects the distinctiveness of the Northumbrian landscape in both its shape and the materials used in its construction.

Its centrepiece is a beautiful Whin Sill grass roof, planted to replicate the unique natural grasslands of the surrounding area. The Sill’s fully accessible living roof sweeps gently upwards, giving visitors a bird’s eye vantage point across one of the UK’s most magnificent landscapes and the UNESCO World Heritage Site of Hadrian’s Wall.

It’s built on the site of our previous visitor centre and YHA hostel at Once Brewed, and is named after the nearby internationally-renowned geological feature, the Great Whin Sill.

Making The Sill

Discover more about the creation The Sill: National Landscape Discovery Centre.


A time-lapse film showing the construction of The Sill: National Landscape Discovery Centre created by Cain Scrimgeour.

Born and Raised in Northumberland

The Sill rises from the Northumberland landscape with little impact on the environment, perfectly mirroring its inspiration; the unique landscape of the Hadrian’s Wall corridor.

Key Facts

  • 80% of the external walls of the building are finished in local materials including whin stone, sandstone and native larch.
  • 90% of the construction employment has come from within the region.
  • More than 3000 local residents helped to shape the concept of the building.

Architects view

The Sill is inspired by The Great Whin Sill, Northumberland’s internationally renowned geological feature, and grows from the landscape that surrounds it. An aerial view of the wider landscape shows these dramatic geological outcrops as diagonal ripples in the landscape. The building is developed as another ripple rising out of the landscape so that the diagonal flowing lines of the building echo the natural undulations and outcrops in the landscape.

We hosted a series of open events and workshops where we discussed site layout, materials and architectural style. The participative design process gave the local community a chance to get involved, voice their opinions and feel some ownership of the project. It also allowed us to draw on a vast wealth of local knowledge and expertise.

Ground floor plan of The Sill

The whole team at JDDK are incredibly proud of what we achieved at The Sill. Our brief was for a landmark building which would become the hub of visitor activities, welcoming visitors and supporting communities throughout the Northumberland National Park. Sustainability and public consultation were at the core of the design process with the finished building inspired by the rugged Northumbrian countryside.

Alison Thornton-Sykes, project architect, JDDK Architects