High Sunderland

When we became involved with the High Sunderland project, there were no major concerns about the building’s structural integrity. Rather, it was simply a prudent step—to make sure everything was in order during this first major overhaul of the building.

Fortunately, we had access to some original construction drawings. By carrying out targeted opening-up work, we were able to verify the accuracy of this information, which helped us develop a solid understanding of the existing structure.

Ensuring Structural Integrity during Refurbishment

The building itself is quite straightforward—it’s essentially a box. Its load-bearing walls are constructed from timber studs, while the flat roof consists of either timber joists or, for longer spans, lattice-steel joists known as ‘Stratford joists.’ The roof plays a crucial role as a structural diaphragm, channelling lateral forces to the racking panels within the load-bearing walls. Basic carpentry and simple bolted joints connect the structural components. After careful evaluation, we found the existing structure to be sound. We focused on addressing localised timber decay, which resulted from long-term exposure to water ingress. Additionally, we fitted bolts that had originally been overlooked during the building’s construction.

Balancing Efficiency and Structural Adaptations

The existing structure efficiently supports its intended load, but like many mid-20th-century buildings, it struggles to accommodate additional weight—even when the increase is minimal. Our main concern was ensuring the new roof insulation wouldn’t pose any structural issues. To do this, we carried out a detailed assessment of the joist capacity, using first principles and referring to contemporary technical literature on similar joists. This process enabled us to confirm that the additional construction could proceed without the need for strengthening work. Ultimately, this project demonstrated how a thorough investigation and reference to primary-source materials can make it possible to adopt a light-touch approach when caring for and rehabilitating historic buildings.