a tensile roof structure tops 3GATTI's low-cost housing prototype for africa

with a project that is affordable, scalable and adaptable, 3GATTI presents their entry to archstorming’s competition to design a house for the jorejick family in tanzania. the brief asked architects and designers to come up with a scheme that could be built not only in tanzania, but across africa. in their response, 3GATTI sought to engineer the best possible solution after taking into consideration the numerous economic and environmental variables that the african context offers.

external view

all images courtesy of 3GATTI

3GATTI imagined a scalable and adaptable design that originates from a simple but ingenious structural idea: a circular wall that alone can sustain a tent roof without the need of any other wall or structural element. in this way, the only major cost is the circular concrete foundation and the round wall of bricks; the rest of the project is very flexible in terms of shape and material options and doesn’t need any other costly elements such as wooden or iron beams and columns.

internal courtyard

for the tensile roof, 3GATTI choose white PVC membrane material; considering the very low cost, the large availability in the tanzanian market, the factory shape customization possibility, the durability, the ease of repair using heated patches, the lightness, and last but not least, the easy transportation. the roof will be composed of three major pieces shaped from the factory and mounted directly on the round wall edge or on a simple iron structure so to keep some distance from the wall. those membrane slices will be kept tight together on top of the patio thanks to a circular iron cable that will distribute the tensions and will be anchored to the ground with another six ropes so to give overall stability and avoid the vibration of the roof in windy days.

plan and night view

under the main roof, there will be false ceilings made of hanging textile sheets to separate the living spaces from the airflow circulating under the roof, from the patio to the outside, passing through the spaces between the alternating bricks of the crown. since the interior walls will not be structural, their dimension is smaller with none or minimal foundations. they can be made of bricks to isolate the sound between rooms and wooden frames with straw and adobe for the ones facing the patio. in the frames, 3GATTI integrated the wooden doors and shelves. the floors are made of rammed earth in most of the spaces and in concrete in the central area to collect the rainwater coming from the roof down to the drainpipe and water tank.

materials and cost diagram

project info:

project name: house for africa

competition: archstorming

architecture firm: 3GATTI

architects: francesco gatti, matteo doglio, hayk martirosyan, martina rotilio, giuseppe conti

structural consultant: francesco negri

design period: june 2020

designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.

edited by: lynne myers | designboom