A first time buyer booking an under construction flat in Bengaluru in 2025 was puzzled when the builder handed over not one contract but two: a sale agreement for a share of land, and a separate construction agreement for the flat itself. It felt like a trick, or at least a complication. It was neither. This two document structure is the normal, legally recognised way apartments are sold in Bangalore, and understanding it is the difference between signing blind and knowing exactly what you are buying and what you are paying stamp duty and GST on. This guide walks through both documents.

The short answer. An under construction Bangalore flat is usually sold through two agreements: a sale agreement for the undivided share of land, or UDS, which attracts stamp duty and registration, and a construction agreement for building your flat, on which GST applies. Courts have confirmed this split is a legitimate way to structure the transaction, provided the documents accurately reflect what is really being conveyed. The trade off buyers must respect: the structure is normal and legal, but you must make sure both agreements are complete, your UDS is correct, and the true value is properly documented, not artificially understated.

Why does a Bangalore flat come with two agreements?

The two agreement structure exists because an apartment is really two things bundled together: a share of the land the building sits on, and the constructed flat itself. Builders separate these into a sale agreement for the undivided share of land and a construction agreement for the building work. It is a long standing, widely used model for selling under construction apartments, not an irregularity, and it reflects the genuine legal distinction between transferring land and contracting to construct.

The split also has tax logic behind it. The land component is a transfer of property, which is where stamp duty and registration sit, while the construction is a service, which is where GST applies. As long as each document clearly states what it covers, this is a legitimate way to structure the deal. The buyer's job is not to be alarmed by the two papers, but to read both carefully and make sure, between them, they add up to the flat you think you are buying.

What is the sale agreement for the undivided share of land?

The sale agreement, and the sale deed that follows it, conveys your undivided share of the land under the building. Your UDS is the proportion of the total land that comes with your flat, and it is transferred to you as a registered interest in the land. This is the document that carries stamp duty and registration charges, because it is the conveyance of an interest in immovable property.

What matters for a buyer is that the UDS is correct and clearly stated, and that the sale deed is actually registered. A Karnataka High Court judgment, discussed in an analysis of the building versus land question, confirmed that where a sale deed conveys only an undivided share in land without mentioning the buildings, it is that land share which is legally conveyed. So the sale deed defines your stake in the land, and getting the UDS right in it is one of the most important things you do in the whole purchase.

What is the construction agreement?

The construction agreement is the contract under which the builder constructs your flat on the land whose undivided share you are buying. It sets out the specifications, the payment schedule tied to construction stages, the timeline, and the builder's obligations to complete and deliver the flat. Unlike the sale deed, it is a contract for construction services rather than a conveyance of land, which is why GST applies to it rather than stamp duty.

For a buyer, the construction agreement is where the details of the actual home live: the finishes, the area, the delivery date and the penalties for delay. It deserves the same careful reading as the sale deed, because a weak or vague construction agreement leaves you exposed on exactly the things you care about most, the quality and timing of your flat. Read the two agreements together, so the land you are buying and the flat being built on it line up into a single, coherent purchase.

One thing to watch is that the two agreements share a consistent story about area and price. The undivided share in the sale deed and the flat described in the construction agreement should refer to the same unit, and the amounts across both should add up to the real, total price you are paying. Where the numbers in the two documents do not reconcile, or a large part of the value seems to disappear into a vaguely worded construction contract, that is a sign to pause and ask questions.

How do stamp duty and GST split across the two agreements?

The two agreements carry two different charges, and knowing which is which helps you budget honestly. Stamp duty and registration are paid on the land component, through the sale agreement or deed for the undivided share, because that is the transfer of an interest in property. GST applies to the construction component, under the construction agreement, because that is a service.

The law is clear that stamp duty is charged based on the contents of the deed, so if the sale deed conveys only the undivided land share, the value of the construction is not automatically added to it for stamp duty. Courts have recognised that parties may structure their transaction to manage stamp duty, as long as the documents are clear and reflect the true nature of what is conveyed. What a buyer must not do is let this structure be used to understate the real value, since an artificially low declared value can create tax and legal problems down the line. Our guides on Karnataka stamp duty and registration charges and on GST on under construction property cover each charge in detail.

Sale agreement versus construction agreement: how do they compare?

The two documents do different jobs, and this table keeps them clear.

Read the table as two halves of one purchase. Neither document alone gives you a finished, owned flat; together they should. The buyer's task is to make sure both are complete and consistent, so nothing important falls into the gap between them.

What should a buyer verify across both agreements?

Because your flat is documented in two places, your checks have to span both. Run through these before you commit.

1. Confirm your undivided share of land is correctly stated in the sale agreement and deed.
2. Ensure the sale deed for the UDS is registered, not left as an unregistered agreement.
3. Read the construction agreement for specifications, area, timeline and delay penalties.
4. Check that the two agreements are consistent and together describe your actual flat.
5. Understand which charge, stamp duty or GST, applies to which component.
6. Ensure the true value is properly documented and not artificially understated.
7. Have a lawyer review both agreements together before you sign either.

These checks connect to the wider due diligence any Bangalore apartment buyer should do, from verifying the project to confirming the undivided share behind your ownership. Reading both agreements as a pair, with a lawyer, is what turns a two document purchase into a single, well understood one.

Where does the bank's tripartite agreement fit?

If you take a home loan on an under construction flat, a third document often enters the picture: a tripartite agreement between you, your bank and the developer. It is a three party contract that governs how the loan is disbursed against construction stages, the developer's obligation to complete and register the property, the bank's security interest, and what happens if any party defaults. It sits alongside the sale and construction agreements rather than replacing them.

For a buyer, the tripartite agreement is worth reading closely because it ties your financing to the builder's performance. It is where the bank's disbursement schedule and the builder's delivery obligations are aligned, which protects you if the project stalls. Together, the sale agreement, the construction agreement and, where relevant, the tripartite agreement make up the full documentary picture of an under construction Bangalore flat, and a careful buyer understands how all three fit before signing any of them.

Frequently asked questions

Why do Bangalore flats have separate sale and construction agreements?

Because an apartment combines a share of land with a constructed flat. The sale agreement conveys your undivided share of the land, while the construction agreement covers building the flat. This two document structure is a long standing, legally recognised way to sell under construction apartments, and it reflects the genuine distinction between transferring land and contracting for construction work.

Do I pay stamp duty and GST on the same amount?

No. Stamp duty and registration apply to the land component through the sale agreement or deed for the undivided share, because that is a transfer of property. GST applies to the construction component under the construction agreement, because that is a service. The two charges fall on the two different parts of the transaction, not on the same value twice.

What is undivided share of land in this structure?

The undivided share, or UDS, is the proportion of the building's total land that comes with your flat, transferred through the registered sale deed. It is the land interest you actually own as an apartment buyer. Confirm the UDS is correctly stated in the sale agreement and deed, since it defines your stake in the land.

Is the two agreement structure legal?

Yes. Courts have confirmed that parties may legitimately structure a purchase with a sale deed for the undivided land share and a separate construction agreement, as long as the documents are clear and reflect the true nature of the transaction. What is not acceptable is using the split to artificially understate value, which can create tax and legal problems later.

Last updated 14 July 2026. PropNewz Team.