Lack of quality in the South African construction industry is causing various problems for different stakeholders. The causes of this lack in quality are due to various different attributes. Corruption has become one of the leading causes with regards to lack of quality. Quality assurance can mitigate or eliminate defects through the implementation of a quality management system. Defects manifest primarily through cracking, dampness, detachment, and water leaks. Defects are categorized as structural, subsidence, acoustic and thermal. In terms of time, defects are either patent or latent, and can be discovered through observation, inspection and various tests. The causes of defects are ultimately due to error or omission, either during design or during the construction phases. Defects may also result due to procurement related factors, such as appointment of incompetent contractors. The result of defects is customer dissatisfaction, rework and disputes. Non-conformance to requirements results in rework and this in turn contributes to time and cost overruns. The aim of this research was to investigate the greatest cause that leads to defects in houses; the most common type of defect; and why projects fail in term of project management terms (due to defects). Results of quantitative research amongst professionals within the construction industry in the Western and Eastern Cape of South Africa as well as literature that has been reviewed form the basis of this study. Architectural practices, consulting engineering practices, and general building contractors were selected on a random sample basis, and surveyed using an online questionnaire. The study revealed that inadequate artisan skills is the biggest cause leading to defects in houses, and that cracks are the most frequent type of defect occurring. Projects fail in project management terms because of defects as the construction time of the projects are increased. The study revealed that construction related causes of defects dominate over design related causes. This study should be of value to both construction industry professionals as well as their clients.