The performance of building materials used for exterior finish cannot be ascertained precisely through simulation or laboratory experiments, however, it requires that the materials are applied on substrates and placed under natural environmental condition to experience the actual changes possible over a period of time. However, universal usage of paint for walls in public and private buildings for decorative and protective functions remains the most aesthetic expression in Nigeria. The planning of maintenance works is based on predictions of the time when the critical elements of the built assets will reach degradation levels that exceed acceptable values. This paper employed the use of statistical model in determining the service life of external paint finish in Wuse Housing Estate, Abuja which falls under savannah climatic zone for architectural design in Nigeria and developing a guide for maintenance planning of external paint finish. The study is a survey research type conducted in the Government Residential Estate that use paint as external finish in Abuja. The total number of buildings in the study area is 1,000 and a sample size of 114 buildings was used. Data was collected through structured questionnaires. Findings revealed that the average service year for the external paint finish in savannah climatic zone in Nigeria is 2 to 5 years. These findings also contradicted the established lifespan of paint in the temperate region put between 5 and10 years.