An open shaft or court in a building designed to bring natural light and ventilation to interior spaces, commonly used in dense urban construction and basement areas.

A lightwell is an open shaft or court in a building designed to bring natural light and ventilation to interior spaces, commonly used in dense urban construction and basement areas. This architectural feature creates a vertical opening that extends from the ground level or basement up through multiple floors, allowing daylight to penetrate deep into building interiors that would otherwise be dark. Lightwells are essential elements in urban architecture, providing natural illumination and air circulation while maximizing building density on constrained sites.

The primary purposes include bringing natural light to interior and below-grade spaces, providing natural ventilation and air circulation, meeting building code requirements for light and ventilation, enabling windows in basement and interior rooms, reducing reliance on artificial lighting during daytime hours, improving indoor environmental quality and occupant comfort, and maximizing usable space in dense urban developments.

Types and configurations involve exterior lightwells, interior courtyards, basement lightwells, and rooftop lightwells for different building applications and site conditions.

Fun Fact: Lightwells have been used since ancient Roman times, with examples found in Pompeii! Victorian-era buildings in cities like London and New York extensively used lightwells to bring light to narrow row houses. Some modern lightwells incorporate mirrors or light-colored surfaces to maximize light reflection. Interestingly, the world’s deepest lightwell is believed to be in a Hong Kong skyscraper, extending over 40 stories down from the roof!