Repairs required to fix a defective instrument or building which requires serviceability. Multiple types of repairs are available based on the type of machineries, equipments and products used. Some require basic works like electrical, plumbing, carpentry, computers, air conditioning, printers, etc., where as others require more indulged activity such as machinery break down.
While repairs are fixing activities, Retrofitting is done on old buildings or instruments where external parts or items are embedded to the defective piece to hold it better. In buildings especially where they are damaged or cracks are formed, retrofitting is done by means of adding chemicals or other compounds which closes them and forms a stronger bonds
Retrofitted equipments and buildings at times strengthens the part to which it is fitted as there is an external bonding agent used to fix the problem.