(1) The scope of Eurocode 8 is defined in EN 1998-1: 2004, and the scope of this Standard is defined in (2), (4) and (5). Additional parts of Eurocode 8 are indicated in EN 1998-1: 2004, . (2) The scope of EN 1998-3 is as follows: To provide criteria for the evaluation of the seismic performance of existing individual building structures; To describe the approach in selecting necessary corrective measures; To set forth criteria for the design of retrofitting measures (i.e. conception, structural analysis including intervention measures, final dimensioning of structural parts and their connections to existing structural elements). NOTE For the purposes of this standard, retrofitting covers both the strengthening of undamaged structures and the repair of earthquake damaged structures. (3) When designing a structural intervention to provide adequate resistance against seismic actions, structural verifications should also be made with respect to non-seismic load combinations. (4) Reflecting the basic requirements of EN 1998-1: 2004, this Standard covers the seismic assessment and retrofitting of buildings made of the more commonly used structural materials: concrete, steel, and masonry. NOTE Informative Annexes A, B and C contain additional information related to the assessment of reinforced concrete, steel and composite, and masonry buildings, respectively, and to their upgrading when necessary. (5) Although the provisions of this Standard are applicable to all categories of buildings, the seismic assessment and retrofitting of monuments and historical buildings often requires different types of provisions and approaches, depending on the nature of the monuments. (6) Since existing structures: (i) reflect the state of knowledge at the time of their construction, (ii) possibly contain hidden gross errors, (iii) may have been submitted to previous earthquakes or other accidental actions with unknown effects, structural evaluation and possible structural intervention are typically subjected to a different degree of uncertainty (level of knowledge) than the design of new structures. Different sets of material and structural safety factors are therefore required, as well as different analysis procedures, depending on the completeness and reliability of the information available.