Shading Applications for Effective Control of Daylighting in Regional Banks, Port Harcourt, Rivers State

Abstract

Shading devices are an important but underutilised architectural design tool for commercial bank buildings in tropical climates. Regional bank buildings in Port Harcourt, Rivers State, Nigeria, operate in a tropical humid climate with high, near-overhead sun radiation throughout the year but have almost no purpose-designed external shading. The struggle between solar heat gain and thermal comfort has resulted in a built culture of opaque facades and interior window coverings that exclude sunshine while negating energy conservation. This study investigates shading applications for effective daylight control in regional bank buildings in Port Harcourt, Rivers State, intending to identify architectural principles for resolving the heat-daylighting conflict via exterior shade. Using a qualitative multi-case research design, the study uses direct and participant observation of two Port Harcourt bank buildings (Parallex Bank, Trans-Amadi Road; Providus Bank, Olu Obasanjo Road), structured key-informant interviews with facility managers at four regional banks, and secondary case study analysis of two internationally recognised daylighting-responsive banking buildings: the BMCE Bank Branches in Casablanca, Morocco (Foster + Partners, 2011), and the Lombard Odier 1Roof Headquarters, Bellevue. The findings show that both local bank buildings lack efficient external shading, necessitating the management of solar heat intake either with internal blinds that cancel available daylighting or with minimum fenestration that eliminates heat and light. The international case studies demonstrate that climate-calibrated external shading systems, specifically 200mm-deep perforated stainless steel mashrabiya screens at BMCE Bank and cantilevered concrete floor slab overhangs at Lombard Odier, successfully decouple solar heat gain from daylight admission in their respective climatic contexts, allowing naturally illuminated, thermally comfortable banking interiors without recourse to interior blinds or artificial lighting. The paper contextualises these findings within the current literature on shading device performance in Nigerian and tropical climates, and it ends with six climate-calibrated design recommendations for incorporating external shading into the envelope design of regional bank buildings in Port Harcourt.