We were engaged to investigate persistent dampness affecting an internal staircase landing during heavy rainfall events. DTCE were engaged to investigate the issue and found that when the staircase was originally installed (date unknown), the existing concrete foundation wall was undermined, and a brick wall was built in front to retain the soil. No drainage or waterproofing was installed, leading to moisture inside the house.

To address this, DTCE designed a new internal retaining wall to properly support the undermined foundation and prevent water penetration. The solution also required reconfiguring the staircase landing, including removal of the lower step and local adjustments to floor and ceiling levels to maintain functional head clearance. A new timber beam was introduced to support the first-floor structure, where levels were modified.

The retaining wall design considered conservative soil parameters, seismic loading in accordance with MBIE Module 6, and the influence of a nearby existing retaining wall. The final solution provides a robust structural and moisture management outcome within a constrained internal space.