Building defects is one of the major components of building problems that significantly needed attention. Minor defects can develop into serious ones, causing failure or sudden collapse, endangering lives and becoming more costly to rectify. As the researcher observed, most defects presented on the Tepi town buildings, due to absence of a serious follow-up and maintenance are: cracking, peeling of paint, defects on plastered structures, defects of roof, defects of rainwater goods (downpipes, gutters, and eaves), defects of stair, dampness penetration and vegetable growth on building. Based on the questioners and interview results the most dominant causes of defects in Tepi town is poor quality of materials with the highest mean rank value 4.21 and also other causes are poor workmanship with mean score value 4.05, inadequate supervision 3.73, poor maintenance during defects occurred 3.70, poor construction practices 3.72, Mix design problems 3.66, poor management system 3.68 and dampness problems 3.61 The methodologies would be applied to achieve the objective of the research, data had been taken literature survey, problem identification by field surveying, design of data collection methods observation, interview & questioner ), organized data, data-analyzed and conclusion drawn from the result of data analysis. The researcher concluded that defective in building construction is mostly a result of poor quality of materials, poor workmanship, inadequate supervision, poor maintenance, poor construction practices, and poor management system and most of it can be attributed to poor building materials and poor workmanship. The rate of defective construction can be minimized by the use of quality building materials, competent workmen, proper management system and adequate supervision.