You need NOC of other flat owners to carry on construction of additional floor 

2) bargain with him offer to pay Rs 2 lakhs but if he is adamant pay Rs 4 lakhs 

Yes,Definitely it is possible. 

Please approach qualified architect who would prepare blueprints for your third floor plan to be submitted to MCD for approval..

MCD would not sanction floor plan without NOC 

For additional construction consent of other flat owners is required 

1. For raising construction of permanent nature taking prior permission from the local Municipality or the Panchayat  is mandatory .

2. Therefore before you add any floor do submit a building plan sketched by a an architect and submit the same before the Municipality for its approval. 

3  Since you are not the owner of the whole building then unless and until you are sole owner over the roof as well you can not make addition of the floors. 

The law is clear that you have to obtain NOC from other occupants of the building. 

You can negotiate the amount with the ground floor occupant and settle the issue amicably. 

If you plan to tackle this issue legally   he may obtain a stay order against the proposed consultation and it may take years for you to start it afresh. 

Even MCD would be insisting NOC from other floor owners to sanction approval. 

It's up to you to plan further. 

Once you submit the plan for approval,  the first question by MCD shall be the NOC from other floor owners. 

Don't cut a sorry figure at that time. 

Dear sir/ma'am,

You do not require an NOC from the owner of first and second floor. Even though such practice of demanding NOC from other floor owners continues, the same is completely illegal and can be challenged in Delhi High Court. In fact there have been such cases where the court has directed MCD to allow the construction of additional floor without such NOC.  

There is no need to bow down to such pressure tactics and spend so much money.  

You can contact me or any other Delhi based lawyer dealing with such matters. I can provide you with a thorough legal opinion after obtaining all the details.

Ask the same under RTI to them under which provision they are seeking such noc

Yes, it is compulsory.

Kindly check your rights, what is written in the agreement at the time of purchasing this flat. If the rights are to construct than no need to take NOC from other members. 

If the rights are to use only than you need to take NOC from other members. 

Dear Sir/Madam,

It is suggested that said NOC from other floor owners is necessary and then only you may approach the MCD for 3rd Floor plan sanction. 

Roof comes under common area. All have equal share. If you have exclusive uninterrupted right on roof than dont care for NOC and proceed with construction after sanction by MCD.

MCD may ask for NOC which you have to manage.

NOC from others are not mandatory but approval from MCD is mandatory for additional vertical and horizontal construction in the premises sdding to Original Approved Plan.

You should file an application before the municipal corporation for granting you permission. The permission can be sought too and any reasonable demands may be agreed to.

NOC is required.

IT can be sanctioned if you show every other thing in order.

- Since, you are owner of the second floor portion only , then even if competent authority will allow you to construct extra floor , then the other owner of first & ground floor can lodge their compliant before the MCD against the said construction on the ground of building poor structure etc. 

- But , after inspection of the building , if competent authority i.e. MCD allows you construct extra floor , then the permission of other owner not required . 

- Otherwise, you have to amicable settle the matter with the owner of other floors. 

Yes, NOC from other floor owners is required.

you need NOC from other owners. you can construct third floor over the said property once you obtain NOC.

the legal way to construct is to apply for sanction of site plan of the proposed third floor to the municipal corporation of your area. after completing all the formalties they shall issue sanctioned site plan to you. Thereafter you can raise construction. 

Without Noc they cannot sanctioned. 

1. You don't need NOC from owners of other floors because you have roof rights. 

2. You just need to take approval for construction from MCD.

3. MCD will sanction plan without NOC from owners of other floors.