Abstract

Ethiopia is one of the developing countries; and many projects are being carried out with some of the firms acting unprofessionally, leading to lots of defects in buildings. This study was focused on identifying the types of defects and assessing the causes of defects occurring in residential and office buildings located in North Shoa zone, Ethiopia. To identify the types and causes of defect, questionnaires surveys were distributed for persons involved in the construction industry including clients, consultants and contractors. The data received in the questionnaires were analyzed by Relative Importance Index (RII) method to determine the relative importance of each factor, and the Spearman rank correlation coefficient was determined to test their significance. Observations were also done on buildings that suffered from the defects in the study area; and foundation, wall and window bay cracks were observed. The top causes of the defects in building construction in the study area according to data collected were lack of consultant timely response and proper solutions; unavailability of professionals for material control; delay of construction material delivery; shortage of construction equipment; and lack of coordination between professionals during design. The Spearman rank correlation for causes of defects in the building indicated that there is no positive significant relationship between stakeholders. These results showed that there was a problem of taking responsibility. Finally, to minimize the problem of defects, various minimizing measures should be taken. These may include; control the quality of design, provide appropriate supervision, train professionals on construction and manpower management, arrange the meeting for stakeholders for proper communication and coordination, and creating awareness on construction defects.

Key words: Construction, defect, defect causes, Relative Importance Index (RII), correlation analysis, minimizing defect.