I have some questions about the additional floor. 1 It is desired to add an additional floor to an existing building whose first four floors were built with 25 × 50 columns. In the performance analysis to be made for the additional floor, is it necessary to convert the existing 25 × 50 columns by 30 × 50, that is, if sheathing is done, if it is 25 × 50 If the existing column is saving the column dimensions of the additional floor will be dimensioned according to the existing lower floor column dimensions or according to the new regulation rules 2 Building height 17.5 meters with a hollow block In an existing building Earthquake zone can also Dts1 additional floor 3 If this building was in dts 3 zone Could it be possible to make an additional floor without curtains?