Diola Impluvium House

The impluvium house (French case à impluvium) is a traditional dwelling of the Diola, or Jola, people of the Casamance region of southern Senegal, a humid coastal zone of forests, rice fields and mangroves. Its defining feature is a thatched roof that drains not only outward but also inward, into an open central court where rainwater collects.

Form

The house is built around a central open court. Thick walls of sun-dried mud brick with an earth plaster enclose the rooms, and a timber structure carries a thatched roof. The roof rises to a ridge and then slopes both outward, over the external walls, and inward, toward an opening over the court. In architectural terms the opening is the compluvium and the basin below is the impluvium, the same words used for the Roman atrium house.

Water collection

During the rainy season, water running down the inner slope falls into the low-walled central basin. The architect Dennis Holloway, who has studied the form, notes that the collected water served as a drinking supply. In some surviving houses the court also works as a garden or animal pen and fills completely with water at the height of the rains.

Climate performance

The thatch shades the thick earth walls from the sun and limits heat gain, while the open centre allows air movement and evaporative cooling. The combination suits a hot, wet climate close to sea level.

Where they survive

Examples are found in or near villages including Enampore, Séléki, Affiniam, Oussouye and Mlomp. A visitor survey published in 2012 found that surviving impluvium houses could be counted on the fingers of two hands, most dating from the second half of the 20th century. Several now function as village guesthouses (campements villageois), and the impluvium at Enampore was rebuilt around 2011. Newer buildings, such as a house at Oussouye completed in 2004, have reinterpreted the type with clay walls on concrete slabs.

The impluvium houses of the Bandial kingdom are on Senegal's tentative list for World Heritage nomination.

Related types

Casamance also has multi-storey earth houses (cases à étages), notably at Mlomp, built of clay walls with palm-wood floors and straw roofs. Compluvium courtyard houses also occur among the Igbo, Yoruba and Edo of southern Nigeria.