First, you please clear whether you are residing on rented premises or ownership premises.
If premises is rented, you will be entilted to eqivalant carpet area in new redeveloped building as per law and you will remain tenant in the said new building and your rent will be more as per standard rent. Here, you can negotiate with the landlord / developer for extra area. Now a days, in many cases, landlord sells asset to the developers, who in return gives ownershp tenanments to the tenants with equvalant area or more depending upon circumstanses of the case.
In case of housing society, the committee should invite tender for redevelopment with speccific points that how much extra area they will get and about corpus fund, etc and negotiate more favourably.
In both the cases, developers offer rent for alternate accomadation till project complte.