Much empirical work has been undertaken on housing production, investment levels and on the changes necessary to increase the supply of housing at a national level. The implicit assumption in these perspectives, that owners buy and sell housing as an adjustment process, is not realised in all housing markets around the world. In fact, in a number of developing countries houses are seldom bought or sold: one such country is Ghana. Here traditional economic perspectives on modelling an owner's decision to extend by comparing it with his decision to sell and move are largely irrelevant. This paper seeks to make a contribution to the analysis of housing supply by developing a housing extension model for the Asante culture in Ghana. The model is evaluated in a two-step econometric analysis of the decision to extend. In the first stage the probability of extending is modelled as a function of household characteristics, while the second stage predicts the amount spent on the extension.