Constructing another floor at a later time

[tendlu]

Say one is currently constructing G+1 and would like to do another floor, second floor, to make it G+2 at a later time (say a couple of years from now). What all things needs to be considered and done right now during the current construction itself. Few things for clarifications:

a) Is it advisable to do it at a later time? pros & cons

b) Do we have to leave extension rods for columns (& anything else) for the next (future) floor?

c) If extension rods are left, what should be the height of the extension rods?

d) Would the extension rods cause any issues to the structure, like rusting etc?

Long question, but just wanted to be clear

[tendlu]

I am told 3' of extension rods for the columns should do it for later construction to extend the columns. Can someone confirm this?

Also can you please let me know what to cover these extension rods with - concrete or chipped bricks? If concrete what is the recommended ratio?