Repair is the process of restoring something that is now damaged, brock or deteriorated to fair condition and good quality. Rehabilitation is defined as the process of improving and returning the building or structure or ground to its previous well condition. Repair and rehabilitation is useful tool to satisfy the buildings functional requirement. Any structure has to be structurally tough and functionally suitable for fulfilling the condition of good structure as per limit states. In the present study it is analyzed that how rehabilitation is insufficient for a structure sometimes if the building has not maintained properly after its construction. Some case studies of Older buildings has been taken in consideration and it is revealed that if the building have been kept in maintenance or the building could have been well monitored that its condition could be more better that present deteriorated condition. Any structure must be monitored for its health and suitability for time to time utility. Maintenance of the structure is an asset for monitoring. Various NDT techniques and visual inspections have been carried out to justify the suitability of structural health monitoring. It has been observed that after the construction the building is used to the utmost utility without considering the maintenance and monitoring which leads to sudden deterioration and damage. Efforts have been made to clarify the importance of repair, rehabilitation, deterioration, maintenance, health monitoring and corrosion for a building. Utkarsh Nigam | Rajneesh Sharma "Rehabilitation of Buildings for Functional Unsuitability: Need of Structural Health Monitoring" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-3 , April 2018, URL: https://www.ijtsrd.com/papers/ijtsrd10848.pdf