Sustainability and Environmental Design
Passive design first
Sustainability questions reward principles applied to Nigerian climate rather than labels. In the hot-humid south, prioritise shade, cross-ventilation and air movement; in the hot-dry north, use thermal mass, small openings, courtyards and night ventilation. Orient the long axis east-west, put glazing on north and south, and shade east and west with screens, deep reveals, verandahs or planting. Light-coloured, insulated or reflective roofs cut heat gain, and stack and cross-ventilation reduce reliance on mechanical cooling. Daylight should reach habitable rooms without glare.
Resources and impact
Water: low-flow fittings, rainwater harvesting, greywater reuse for flushing and irrigation, permeable paving for recharge. Energy: reduce loads first, then specify efficient equipment, then add solar photovoltaic or thermal systems sized against a realistic load estimate. Materials: low embodied energy, local sourcing, recycled content, durable and repairable assemblies. Site: retain topsoil and vegetation, control erosion and silt, and manage construction waste. Large projects may need an EIA with an environmental management plan; certification tools help communicate performance, but the design decision matters more than the certificate.
Worked example
A window head sits 1.5 m below a projecting roof. To shade it fully at a noon solar altitude of 60 degrees, the overhang must project 1.5 / tan 60 = 0.87 m. Shorter projections shade only the upper part of the glass, so add vertical fins on east and west façades where the sun is low.
Traps
Specifying photovoltaic panels to rescue a badly oriented, unshaded building; treating green as a landscape feature; ignoring maintenance and occupant behaviour in the sustainability narrative.