This technical paper is based on a study commissioned by a ready-mixed supplier to determine the reasons why hairline cracks developed in the floor slabs of newly hardened concrete. The study was intended to ascertain the physical environment and construction site conditions that affect the development of concrete and point out ways in which to avoid cracks from occurring. Using a combination of qualitative and descriptive information, the study was woven using available documents, which include location map, design drawings, and reports of material tests conducted which provided additional information. Hairline cracks discovered were typical of concrete slabs that experienced plastic shrinkage. Physical and environmental conditions exacerbated by inappropriate construction practices resulted in the development of plastic shrinkage cracks. Recommendations on possible “crack repair” methods or probably even avoidance are enumerated with the end in view of finding practical use in construction. The value that can probably be attributed to the study could be along increasing efficiency in construction as well as efficient use of materials.