Reinvention of an African Mud Hut
Mud homes have traditionally been constructed in Ghana, but have fallen out of favour due to a perception that the method is cheap, old, and difficult to maintain. This is not necessarily true, as Ghana has rich laterite soil which is well-suited to earth construction. A new and innovative design in a vibrant urban community can promote earth construction as modest, affordable, and appropriate to the locale and to create a shift in construction from imported materials like concrete back to natural materials. The proposed design in Obuasi should provide a catalyst for new, owner-built homes in the region made out of earth and other affordable local materials.
Obuasi is a cosmopolitan city in the Ashanti region of Ghana, featuring a rich history of international involvement through its gold mining operations. There has recently been a shift from deep shaft mining to surface mining, which has led to an abundance of available laterite, perfect for building. Residents of Obuasi build their own homes in the metropolitan centre close to amenities and services, leading to a dense development of homes of many shapes, sizes, and styles. A new modern home in the neighbourhood would fit well with the diverse building vernacular. The proposed resident for this design is a mine worker and his brother – a local merchant – along with their immediate families. They will be able to readily acquire laterite from the mines and building materials from the town, and assemble the structure.
The proposed design draws from the traditional courtyard house, featuring a central open area protected from the street by a wood screen walls with doors. The living spaces (bedrooms, living room) are located to the east to take advantage of the prevailing northeast winds, and also to avoid the hot afternoon and evening sun. The service rooms (kitchen, latrine, storage) are located to the west, separate from the living spaces to avoid sound, odours, and heat from cooking and the hot sun. The exterior walls feature ventilation slits around the perimeter to permit air flow from all sides while also providing privacy and security.
Natural ventilation is very important in the proposed design, with the angled roof panels capturing wind and diverting it into the home, and slits in the exterior walls capturing air from all sides. Interior partitions are permeable, so that air can pass through; and do not extend to the roof so that air can pass over. The wood floor is raised in the living area so that air can circulate under the floor, from the exterior ventilation slits, between the joists, and through gaps in the flooring. The kitchen is separate from the living space, so that heat from cooking can vent out through the courtyard rather than into the living spaces. These measures ensure that the home does not get overheated, and fresh air is constantly provided to the inhabitants.
To promote earth construction the proposed design features exterior rammed earth walls. Constructed with two widths of forms (5’-1” wide and 6’-6” wide), two sections of wall can continuously be under construction while other elements such as roof trusses and partitions can be built at the same time, increasing construction efficiency. Wood truss roofs with large overhangs protect the rammed earth walls from rain and direct sun. All framing is to be Dahoma wood as it is fast-growing, abundant, inexpensive, and durable. The trusses lift the roof surface above the rammed earth walls to capture natural ventilation on all sides. The roof sections are covered with corrugated metal panels, a cheap and effective material which also reflects a lot of incoming solar heat. Water is directed from the roofs through gutters and downspouts to grade to avoid infiltration into the interior.