The problem of incompatibility in the architectural design of some houses with the requirement of their residents is considered to be one of the residential areas problems, the alteration in the facades can be seen as an aspect of the user trials to reconcile architectural design of his house with his actual needs, Which makes the façade loses its original design and tern into a group of small facades, each reflects its user's preferences without any relation with the whole façade. The aim of the paper is to study the possibility of dealing with alterations in the buildings facades as an indicator to measure the design suitability. The paper discusses the concept of design suitability and deferent approach of designing the residential buildings facades in its first and second parts, In the third part of the paper, the alterations in the residential buildings facades is classified into two types, the first one is unintentional, but it is an aspect of the user's trail to meet the missed functional needs in the original design of his house, while the second type is the intentional alterations for either the seek of the individual identity or aesthetic reason from the user's point of view. The low income housing projects with their replica units and monotonous facades is the ideal environment for the second type of buildings facades alterations, in the last part; possibilities of take advantage of studying the alterations in the residential buildings facades is discussed. The paper concludes that Alterations in the buildings facades can be considered as an indicator to measure the design suitability (functional or incorporeal), but designers can not take advantage of them specifically in the architectural design of the future residential projects. In the end; the paper presents some recommendations which can be useful in dealing with the problem of alterations in the buildings facades in the new designs of the mass-produced housing projects.