Floor extension

Hello Gupta Sir,

Thanks for sharing your valuable inputs for all these year. Reading your inputs gives immense relaxation while costing.

Coming to my query, I have G+1 floor house build on 30*40 site in Bangalore. We have 12 columns sizing 9”*16” (4 nos 16mm bars, 2 nos 12mm bars in btw and ring of 8mm), beam size 9”*9” and the Slab thickness is 6”.

Can I construct another floor on this?

If yes, then I am planning to construct another floor of 850 sqft, final floor no more construction in future. My few technical question are, can I decrease the size of the column to 9”*12”? And slab thickness to 5”?