Hello Sandesh, First of all, there is a structural issue, as it might lead to putting an additional load on the structures. In case the structure fails, Builder will simply raise his hand saying that you are the culprit as you have done illegal construction and putting an additional load (that is why he will not give it in writing allowing you to do the change). In case, there is a big issue like building collapse and death etc, you may able to enjoy the life behind bars as well. So, better check CIDCO rules and hire an architect in this matter for any future litigation.
On the other hand, if someone from your society or otherwise complains to CIDCO, you may get a notice to remove or else they will demolish and recover the cost from you.
Hi Sandesh, I would advise you to please check CIDCO rules for modification of flat. Better, hire a certified architect who knows the rules and can show you the same in writing.
I am agreed with Mr. Deepankar. But keep your society (even if it is not formed) members informed. If you are doing everything as per procedures allowed by CIDCO like, for example, no RCC, no modification to pillars/slab that puts extra load on bldg or weakens then most may cooperate.