In many parts of Africa, traditional household structures consisting of an extended family headed by a patriarch are giving way to other types of households -- e.g. nuclear families, female-headed households -- as a result of migration, urbanisation and population pressures on land. In this paper, we explore whether traditional norms which determine how resources are allocated within the household are affected by the evolution of household structures. We show that the allocation of resources, for production and consumption, are closer to being efficient in nuclear family households as compared to extended family households. The findings are consistent with the hypothesis that individuals belonging to the same nuclear family have stronger ties, enabling them to commit to more efficient contracts infeasible for those connected through an extended family relation.