Your understanding mixes two different regimes—pre-RERA practice (1990s) and the current RERA framework—so it needs a careful separation.
In the 1990s, builders often followed non-uniform and builder-friendly practices. In many projects, areas such as lofts, flower beds, ducts, etc., were sometimes factored (fully or partially) into what was described as “carpet” or used to inflate built-up/saleable area. There was no standardized statutory definition of carpet area then, which is why agreements typically mentioned built-up or super built-up area with heavy loading.
Under current law, particularly the Real Estate (Regulation and Development) Act, 2016, “carpet area” has a strict definition—it includes only the net usable floor area within internal walls and excludes areas like balconies, terraces, shafts, and typically lofts (unless they are usable floor space at the same level). Therefore, under RERA, a loft is not treated as carpet area in the modern sense.
Coming to your core question on redevelopment:
Your assumption that the builder must consider the “old carpet area including loft” is not automatically correct in law. In redevelopment, the entitlement of an existing member is generally determined by:
the area recorded in the original agreement / society records,
the approved plans and occupation/completion documents, and
the Development Agreement / Permanent Alternate Accommodation Agreement (PAAA) executed during redevelopment.
If the loft area was formally sanctioned in the original building plan and consistently recognized in society records (e.g., tax, share certificate, or agreements), you may have a strong equitable argument to include it in negotiations. However, if it was merely a constructed or builder-added feature without clear legal recognition as part of carpet area, the developer is not legally bound to treat it as carpet area under RERA norms.
Regarding property tax in Navi Mumbai, the area reflected in tax bills is often closer to carpet/assessable area, but it is not conclusive proof of legal carpet area entitlement for redevelopment. It is only one supporting indicator.
In practical terms, during redevelopment:
developers usually offer new RERA-compliant carpet area,
plus additional benefits (fungible FSI, corpus, rent, etc.),
and disputes often arise when old “inflated” or ambiguous areas are compared with new standardized carpet area.
In conclusion, while you may negotiate based on historical usage and sanctioned loft, there is no automatic legal right to demand that the loft be added to carpet area in redevelopment merely because it was earlier counted informally. The outcome depends on documentation, sanction plans, and negotiation strength within the society.
Carpet Area "then" as per the Blue Print of 1990s
It is my understanding that in 1990s, when the Blue Print "then" (Senctioned plan Drawings) shows the Loft with designated name to it as "Loft" "and With its Dimensions", the Builders "then" figured the Loft Area in the Carpet Area (so called "Original Carpet Area"). The Agreement "then" showed only the Built-up/Salable-Area then, which is with about 29% of loading on Original Carpet Area. Carpet Area is stated then (1990s). Also it is understood that the SqMtr shown on the Navi Mumbai Property Tax Bill is "Carpet Area" and not the Built-up Area. So even though as per New RERA rules Loft Area (of approx 33% of the Floor Area) isn't counted in the New RERA Carpet Area, for the Redevelopment, the "Builder should consider the Original Carpet Area (which included the Loft Area)" for the Builder to provide Additional Area (during Redevelopment) on top of that Original Carpet Area. Is that a correct statement? Can you confirm and elaborate on above topics. Thank you.
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Thank you indeed for prompt response. Why the RERA Carpet area definition has to be in picture at all while Original Existing Carpet Area is justified to come up with Carpet Area "then". Let me explain the Floor Area is about 467 sq.ft and the Loft (of about 5.5 ft of height) Area (shown & "designated as Loft with Dimensions") is 130 Sq.Ft. that makes it 597 Sq Ft of Total Usable Carpet Area. So in that basis, the Builder stated and charged for 773 Sq.ft which amounts to about 30% loading on the Carpet Area, which seems very Justifiable (in 1990s'). That said, 597 Sq.Ft seems very correct to considered as Carpet Area. If "only 567sqFt has to be counted as Carpet Area, the Loading Factor turns out at 67%, which is never heard of then in 1990s or even now, for more like "Class 4-5", Old building built around 1990. Now, "in the present time", the Builder for Redevelopment, shouldn't he count the Existing Carpet Area (Original Carpet Area the Member has), to provide an Additional Space on that 597SqFt? And then come up with New RERA Carpet Area after adding the Additional space they like to add/privide. As far as Property Tax Bill, the Property Tax is figured out on the basis of what real Usable (Carpet Area) which could be Rateable (Rentable) to come with Tax amount on the area that can generate Rents on, I believe. So that said, it is Carpet Area on NMMC Tax Bill (and the Built-up Area). I don't mean to argue but my perception is very logical and few AI also confirmed it. But I needed the Lawyers like to provide your inputs and legal justification. Thank you.
Yes builder should consider the existing area as well as FSI and pro raw fsi for the same
The inclusion of loft areas in "original carpet area" for redevelopment can be used by you for negotiations
2)If a loft was part of the Sanctioned Plan Drawings with specific dimensions, it was often considered "net usable area" by builders
3) the square footage on Navi Mumbai Municipal Corporation (NMMC) property tax bills refers to the Carpet Area.
3) For redevelopment, the property tax bill is often used as evidence of the flat's official size
4)Since the loft was a sanctioned, usable space in your 1990s plan,you can insist that builder use original carpet area including loft for redevelopment
You are entitled to a new flat with a carpet area equivalent to the "original premises" plus any negotiated additional area.
2)if a builder charged you for a specific saleable area based on that loft in the 1990s, they cannot now "discount" that same area when returning it to you during redevelopment.
3) builders today get 35% Compensatory/Fungible FSI on top of the existing carpet area to provide extra space. This extra FSI should be applied to your entire 597 sq.ft baseline.
Your statement about the "Original Carpet Area" being the benchmark for redevelopment is a central point of negotiation in current redevelopment projects.In the 1990s, particularly under CIDCO and MOFA (Maharashtra Ownership Flats Act) rules, the definition of "Carpet Area" was less standardized than it is today.
If a loft was part of the sanctioned plan with specific dimensions, it was often considered "usable area." Developers frequently included the loft area (or a percentage of it) in their internal "Carpet Area" calculations to justify a higher Saleable Area.
The Navi Mumbai Municipal Corporation (NMMC) generally levies property tax based on the Carpet Area of the unit.. The area mentioned on your tax bill is often the most "authentic" record of the flat's usable area as recognized by the local authority at the time of the building's completion.
As per RERA the Carpet Area is Net Usable Area with internal partition walls.. It strictly excludes lofts, balconies, and terraces. If a builder only uses the "New RERA Carpet Area" to calculate your 35% extra area, you might lose out on the square footage represented by your loft or flower beds that were part of your original purchase.
In redevelopment, the "Certified Carpet Area" (as per the original Sanctioned Plan and Agreement) is the starting point. If your original 1990s agreement or the society’s records state a certain carpet area (which included the loft), the builder should use that as the base for adding the "incentive" or "additional" area.
You may ensure that your Society's Feasibility Report and the Development Agreement (DA) explicitly define "Existing Area" as the area mentioned in the original registered agreements or the sanctioned blueprints, inclusive of lofts.
Do not let the builder use only a fresh "RERA survey" of the bare floor, as that will naturally ignore the vertical volume of the loft.
The reason RERA is in the picture at all is for future standardization. RERA was designed to prevent builders from selling "super built-up" areas that don't exist. However, for Redevelopment, RERA should only be used as a unit of measurement, not a unit of entitlement.
Your "Existing Carpet Area" (including the loft) is a vested property right. If the loft was in the sanctioned plan, it is part of your ownership.
A builder cannot use a new law (RERA 2016) to retrospectively shrink the physical footprint you purchased in 1990. The 597 sq. ft. is your Base Area. The 35% "Incentive Area" (Fungible FSI) should be calculated on this 597 sq. ft.
If the builder now claims your carpet area is only 467 sq. ft., they are effectively accusing the original builder of a 67% loading, which would have been considered a fraud or a structural impossibility at the time. You can use this "Reductio ad absurdum" (reduction to absurdity) argument in society meetings to prove that the 597 sq. ft. figure is the only historically and commercially consistent base area.
In Navi Mumbai, the NMMC Property Tax Bill is one of the strongest "secondary evidences" you have. Municipalities tax you on what they call "Rateable Value." This value is derived from the "Usable Area." If the NMMC has been collecting tax for 30 years based on a specific square footage that accounts for your loft’s utility, it constitutes an official government recognition of that area as your "possession."
You can argue that the Loft is designated with dimensions in the Sanctioned Plan of 1990. You can file a suit under the provisions of Specific Relief Act, stating that you are entitled to the restoration of the full utility of your original sanctioned area."
You may also add in your arguments that the redevelopment must be 'Area Neutral' at minimum.
That if your existing usable area is X, the new RERA area must be X with incentive and it cannot be X - Loft + Incentive."
You may also argue that while RERA defines how to measure the new flat, the Quantum of Entitlement is governed by the original Agreement for Sale (MOFA) and the NMMC Tax Records.
The reason RERA is in the picture at all is for future standardization. RERA was designed to prevent builders from selling "super built-up" areas that don't exist. However, for Redevelopment, RERA should only be used as a unit of measurement, not a unit of entitlement.
Your "Existing Carpet Area" (including the loft) is a vested property right. If the loft was in the sanctioned plan, it is part of your ownership.
A builder cannot use a new law (RERA 2016) to retrospectively shrink the physical footprint you purchased in 1990. The 597 sq. ft. is your Base Area. The 35% "Incentive Area" (Fungible FSI) should be calculated on this 597 sq. ft.
If the builder now claims your carpet area is only 467 sq. ft., they are effectively accusing the original builder of a 67% loading, which would have been considered a fraud or a structural impossibility at the time. You can use this "Reductio ad absurdum" (reduction to absurdity) argument in society meetings to prove that the 597 sq. ft. figure is the only historically and commercially consistent base area.
In Navi Mumbai, the NMMC Property Tax Bill is one of the strongest "secondary evidences" you have. Municipalities tax you on what they call "Rateable Value." This value is derived from the "Usable Area." If the NMMC has been collecting tax for 30 years based on a specific square footage that accounts for your loft’s utility, it constitutes an official government recognition of that area as your "possession."
You can argue that the Loft is designated with dimensions in the Sanctioned Plan of 1990. You can file a suit under the provisions of Specific Relief Act, stating that you are entitled to the restoration of the full utility of your original sanctioned area."
You may also add in your arguments that the redevelopment must be 'Area Neutral' at minimum.
That if your existing usable area is X, the new RERA area must be X with incentive and it cannot be X - Loft + Incentive."
You may also argue that while RERA defines how to measure the new flat, the Quantum of Entitlement is governed by the original Agreement for Sale (MOFA) and the NMMC Tax Records.
Dear Sir/Madam,
Your maths may look logical, but legally redevelopment area is not decided by loading percentage. Under RERA/UDCPR, carpet area means the net usable floor area of the apartment, while a loft is separately treated in building regulations as a structure for storage, so it is not automatically added as carpet area merely because it is usable.
So, the builder in redevelopment will usually be bound by the area clearly recognised in the old agreement, sanctioned plan and society records; if the old plan shows the loft separately as “Loft”, your claim for that 130 sq.ft. is arguable, but not automatic. Also, the NMMC tax material itself refers to built-up area for fixation of rateable value, so the tax bill is only supporting material, not final proof of redevelopment entitlement.
Your reasoning is understandable from a practical and commercial standpoint, but legally the position operates differently, which is where the confusion arises.
The central issue is that redevelopment today is governed by the current legal framework, not by how areas were perceived, marketed, or internally calculated in the 1990s. That is why the definition of carpet area under present law becomes relevant, even if the original transaction followed a different understanding.
At that time, there was no uniform statutory definition of carpet area, and builders often included lofts and other usable spaces in their internal calculations. However, those practices do not automatically translate into legally recognized carpet area today. Even if a loft is shown in the sanctioned plan with dimensions, it is generally treated as an ancillary or storage space rather than a primary habitable area. Under present norms, such spaces are typically not included within the definition of carpet area, regardless of their practical usability.
This creates the key distinction between what is usable in reality and what is legally recognized. While your calculation of total usable area may be logically correct, redevelopment entitlement is not based on that logic. It is based on what is formally recorded and recognized in legal and planning documents.
In redevelopment, the developer is not obligated to consider what is perceived as original carpet area including the loft. Instead, the baseline is derived from the area reflected in the original agreement, society records, and approved plans, all interpreted in accordance with current legal definitions. If the loft was not legally treated as part of carpet area in those records, the developer can exclude it while computing your entitlement.
Your point regarding loading becoming disproportionate if the loft is excluded is commercially persuasive, but legally it does not determine entitlement. Courts and authorities do not assess fairness based on historical pricing structures or loading percentages. They rely on documented and legally recognized area.
As far as property tax is concerned, while it may be linked to usable or assessable area, it does not conclusively establish legal carpet area for redevelopment purposes. It is only indicative and cannot override statutory definitions or planning regulations.
That said, you are not without leverage. If the loft is clearly shown in sanctioned plans, has existed since the inception of the building, and is consistently reflected in some form within the overall documentation or society understanding, you do have a reasonable basis to raise it during redevelopment discussions. In practice, such issues are often resolved through negotiation, either by way of additional area, compensation, or adjustment in benefits.
Therefore, while there is no automatic legal right to have the loft counted as part of carpet area for redevelopment and to claim additional area over that basis, it remains a valid point for negotiation depending on the strength of your documents and the facts.
Sharma-saab, How could the builder use a new law (RERA 2016) to retrospectively shrink the physical footprint you purchased in 1990. In Navi Mumbai, the NMMC Property Tax Bill is one of the strongest "secondary evidences". Municipalities tax you on what they call "Rateable Value." This value is derived from the "Usable Area." If the NMMC has been collecting tax for 30 years based on a specific square footage that accounts for your loft’s utility, it constitutes an official government recognition of that area as your "possession." the redevelopment must be 'Area Neutral' at minimum. That said, If your existing usable area is X, the new RERA area must be X with incentive and it cannot be X - Loft + Incentive." While RERA defines how to measure the new Shop, the Quantum of Entitlement is governed by the original Blue Print of Sanctioned Plan (per MOFA) and the NMMC Tax Records.
A builder's attempt to use RERA's technical measurement (which excludes lofts) to determine your quantum of entitlement is a common tactic to save costs on the FSI (Floor Space Index) they must provide.
RERA 2016 is a procedural law, not a substantive property law.
RERA defines how to measure space for future sales to ensure transparency. It does not—and cannot—legally strip away physical area that was sanctioned, paid for, and taxed under the Maharashtra Ownership Flats Act (MOFA) in 1990.
If your original agreement and blueprint (the "Sanctioned Plan") show a loft with dimensions, that loft is a sanctioned component of your property. Using a 2016 definition to "erase" a 1990 sanctioned structure is a retrospective application of law, which is generally not permitted unless explicitly stated in the statute.
You can always approach high court with a writ petition to get the relief and remedy to this if the builder is still going ahead with his illegal route for wrongful gains.
Yes your understanding is correct
RERA is a regulatory disclosure law, not an expropriation law. It cannot be used to retrospectively invalidate property entitlements that were legally executed under the Maharashtra Ownership Flats Act (MOFA)Or recognised by local authorities ages ago
2) The "Quantum of Entitlement" for redevelopment is anchored to your original registered agreement and the sanctioned blueprints of that era, not RERA's new measurement
3) As you rightly noted, the Navi Mumbai Municipal Corporation (NMMC) collecting property tax on a specific "Rateable Value" for 30 years is a powerful piece of evidence. Under the principle of Estoppel, a statutory body (and by extension, the builder acting on sanctioned plans) cannot suddenly claim that an area you have been taxed on for decades does not exist or has no legal standing as your possession.
Your argument is commercially appealing, but it overstates the legal position. The law does not work on the principle that “whatever was usable must be protected in redevelopment.” It works on what was legally recognised as carpet area, not what was practically used.
The developer is not “retrospectively shrinking” your area by applying RERA. What is happening is this:
your old transaction was based on a non-standard, loosely defined concept of carpet area, whereas redevelopment today must follow a statutorily defined concept of carpet area. That shift is not retrospective—it is regulatory standardisation.
Your core assumption—that entitlement must be “area neutral” based on total usable area including loft—is not a settled legal rule. Courts have repeatedly held that redevelopment entitlement flows from documented and legally recognised area, not perceived or functional usage.
On your reliance on the sanctioned plan (blueprint), it helps your case—but only to a limited extent. Even if the loft is shown with dimensions, planning law generally treats lofts as ancillary or storage spaces, not equivalent to primary habitable floor area. So its mere presence in the plan does not automatically elevate it to “carpet area” in the legal sense.
On property tax, your position needs correction. Municipal tax (NMMC) is based on rateable/assessable value, which may consider usability, but it is not a legal certification of carpet area ownership rights. Courts treat such records as supporting evidence at best, not determinative proof. They cannot override statutory definitions or contractual records.
Now coming to the most important practical reality:
Your argument is not legally enforceable as a right, but it is negotiationally strong.
If you can show that:
the loft was part of the original sanctioned plan,
it has existed since inception,
it was factored (directly or indirectly) in sale consideration, and
it reflects in some form across documents (tax, plans, society understanding),
then you have a credible basis to demand compensation, additional area, or adjustment.
But the builder is not legally bound to say:
“Old usable area equals to new RERA carpet area.”
Courts do not apply a formula like “X must remain X.” They examine:
what was the legally recognised carpet area,
what is recorded in agreements and society records, and
what is provided under the redevelopment agreement.
That is why developers typically offer:
RERA carpet area (strict definition)
fungible FSI / incentive / corpus / rent
—not a mathematical conversion of old “usable area.”
So the correct legal position is this:
Your theory of “area neutrality based on usable area including loft” is not a legal entitlement.
Your reliance on blueprint and tax records strengthens your bargaining position, not your legal right.
RERA is not applied retrospectively—but it governs how new entitlement is measured.
The outcome will ultimately depend on documentation + negotiation strength within the society.
If you push this as a legal right, you may struggle.
If you push this as a document-backed equitable claim in redevelopment negotiations, you are on much stronger ground.
If you want, I can help you structure a negotiation position or clause strategy for redevelopment so that this point is effectively leveraged rather than lost in technical interpretation.
Okay, What Clause can you suggest? Please provide. Thanks.
The clause must explicitly state that the "Existing Carpet Area" includes the lawful carpet area of the main unit plus the lawfully constructed loft area (often referred to as a mezzanine floor).
2) The Developer agrees to provide to the Member, in the new building, a new flat comprising a carpet area equivalent to the existing carpet area of the existing flat [Insert Area] PLUS the existing loft area [Insert Area], totaling [Total Old Area], along with a minimum 35% additional area as compensatory FSI/fungible area, subject to a minimum of 405 sq. ft., entirely free of cost."
Request that the Schedule of Areas (an annexure usually attached to the Development Agreement) explicitly lists two columns:
Existing Usable Area (as per Sanctioned Plan/Tax Bill): 597 sq. ft.
New RERA Carpet Area Entitlement: [597 + Bonus] sq. ft.
You have an option to approach high court also as a last resort to get your grievances redressed.
Best of luck