Hey there,
I am an Architect with eight years of experience, I represent liquid Architects OPC Private Limited based out in Delhi. We are a group of Architects, Civil Engineers, Interior Designers with Implementation team.
The quoted price is subjective, it would depend solely on size of your built structure, analysis of as built or existing building in terms of structural strength. A site visit is mandatory to give you right figures.
If you are around Delhi NCR we can meet or schedule a site visit which would cost you 5000 a visit. At the end of our analysis we'll document the findings and estimate for repairs and extension of floor.
Hope to hear from you soon.
Thanks,
Ar. Ishan