This paper presents a study of the lasting effects of Portland cement and concrete’s acceptance as a restoration material after the technology came of age in the early 20th century. The paper will highlight the development of modern cement technology while also explaining how it came to be accepted as a viable option in the restoration of heritage structures, and the eventual repercussions of such techniques. Presented in the document are the techniques of early restorations and the most common methods utilized during the grand period of reinforced concrete intervention that occurred during the mid 20th century. After highlighting the various techniques, the mechanisms and modes of deterioration that have plagued such affected structures in the years following intervention will be presented, and likely causes will be identified. Forms of chemical, mechanical, and structural deficiencies all related to the addition of reinforced concrete in systems will be mentioned, and relevant examples will be cited through the use of case studies, with hopes of bringing greater clarity to previously mentioned information within the document. Case studies will be presented where lessons were learned from failures resulting from inadequate restoration practices. The document will conclude with a summary of all presented material and suggestions on what was learned throughout in the years following case studies where failure, deterioration, and premature degradation were induced by concrete restoration materials. An attempt will be made to suggest steps in the future to ensure that problems are avoided in future restorations, and also what must be done with existing altered structures that may be vulnerable in the future. Also, the question of whether reinforced concrete has a place in the field of restoration technology will be discussed.