Buying new apartment in Co-operative Housing

Dear Sir,

Do not proceed with only an MoU.
Ask for a legally binding Agreement for Sale, construction agreement, or tripartite agreement—preferably registered.
If the builder refuses, walk away. This could be a red flag for future litigation or scam.

Dear client,

The usual practice in case of cooperative societies is that you will have to become a member to get any benefits out of that or any ownership rights in the property. When the share is being sold by the one of the members then you must ensure that whatever agreement or MoU you are going to have must also include that member too.
MoU is valid legal document but it has to be seen that in what context the MoU is being executed.

Since you are going to invest good amount of money in this hence you are suggested that you must show all the relevant documents to a good lawyer and get them vetted by the lawyer.

Dear Client,

An MoU on stamp paper is not a legally binding substitute for a registered Agreement for Sale, especially in the case of purchasing a flat through a builder in a co-operative housing society. While an MoU may have some evidentiary value, it does not provide strong legal protection in case of fraud, delay, or dispute, and may limit your ability to take legal action.

Since the builder is asking you to become a member of the society and pay for construction without executing a formal registered agreement, it poses a legal risk. You should insist on a registered Agreement for Sale that clearly outlines your rights, payment terms, and construction details as per applicable laws like WBHIRA or RERA. Before proceeding, it's strongly advisable to consult a property lawyer and verify the society's rules, the builder’s authority, and the legal status of the project to protect your investment.