Overview

Protheroughs were appointed post-planning to deliver the structural design for an ambitious self-build home on the banks of the River Avon. The design features a bold, cantilevered profile that takes full advantage of the sloping site and riverside views, requiring a sophisticated approach to both the sub-structure and the primary frame.

The challenge

The project presented significant geotechnical risks due to the steep slope and proximity to the riverbank. The architectural intent required the building to project out over the bank, creating a large cantilevered balcony. Navigating the balance between the architectural 'lightness' of the cantilever and the heavy structural requirements of the retaining walls was the primary focus.

The structural strategy

We designed a reinforced concrete retaining wall to create the undercroft and lower ground floor, providing a robust 'anchor' for the building. As the structure projects from the bank, it transitions into a cantilevered steel frame. By collaborating closely with the geotechnical engineer and the contractor, we performed a detailed slope stability analysis. This allowed us to specify a traditional pad foundation solution and riverbank stabilisation, avoiding more intrusive and costly piling while ensuring the long-term safety of the site.

Outcome

The result is a striking, stable structure that perfectly achieves the architectural vision. Our intervention ensured that the complex cantilever and slope requirements were met with a buildable, traditional foundation strategy, providing the client with a cost-effective route to completing their ambitious self-build.