A construction glossary for Mumbai flat buyers and society members: 70 terms explained in plain English, from carpet area, OC, CC, IOD, FSI and TDR to MahaRERA, QAC, snagging, dado and coba.
This construction glossary for Mumbai flat buyers explains the words you will meet when you buy a new flat, move into a redeveloped building, sit on a society committee or renovate your home. Brochures, agreements, society meetings and site conversations are full of shorthand: carpet area, OC, CC, IOD, FSI, TDR, QAC, coba, dado. Most people nod along. This page is for the moment you would rather know what the word actually means. It covers more than 70 terms, grouped by where you are likely to meet them, each explained in a few sentences.
It is written by Chamunda Constructions, a civil and finishing contractor in Kandivali West, Mumbai, founded in 2004 by Bhadresh Chavda. The finishing and site terms come from our daily work. The legal, planning and regulatory terms are explained in general terms only; definitions in law are precise and can change, so treat this as a plain-language starting point and not as legal advice. Where a definition comes from a specific law, we say so.
How to use this construction glossary for Mumbai flat buyers
The terms are grouped into seven sections: area and measurement, planning and development rights, approvals and certificates, MahaRERA and buyer protection, redevelopment and housing societies, the building structure, and finishing work. If you are buying a flat, the first four sections matter most. If you are on a society committee, read the redevelopment section. If you are renovating or checking a new flat before possession, go to the structure and finishing sections, and then to our new flat snagging checklist.
Area and measurement terms
Carpet area. Under Section 2(k) of the Real Estate (Regulation and Development) Act, 2016, carpet area is the net usable floor area of an apartment, excluding the area covered by external walls, areas under services shafts, exclusive balcony or verandah area and exclusive open terrace area, but including the area covered by the internal partition walls. It is the figure a developer must use when selling a flat in a RERA-registered project. When comparing flats, compare carpet areas.
Built-up area. The carpet area plus the thickness of the external walls, and often the area of balconies and similar spaces attached to the flat. It is larger than the carpet area, and the exact definition varies from one document to another, which is why RERA moved sales to carpet area. If a document quotes built-up area, ask what it includes.
Super built-up area. The built-up area plus a proportionate share of common areas such as lobbies, staircases, lift wells and sometimes amenities. It was widely used in older sales and advertisements and can be much larger than the carpet area. For RERA-registered projects, the sale must be on carpet area, though you may still see super built-up figures in older paperwork.
Loading. The informal term for the difference between the super built-up area and the carpet area, usually expressed as a percentage. A high loading means much of what was 'sold' was common area rather than space inside the flat. It is a useful number to calculate when looking at older resale flats.
Usable area. An informal term for the area you can actually use inside the flat, close in meaning to carpet area. It has no fixed legal definition, so treat any figure described this way with care and ask for the carpet area as well.
Gross plot area and net plot area. Gross plot area is the total area of a plot. Net plot area is what remains after deductions such as land reserved for road widening or public purposes. Development potential is calculated from one or the other depending on the regulation, so the distinction matters in redevelopment feasibility reports.
Planning and development rights
FSI (Floor Space Index). The ratio of the total floor area that can be built on a plot to the area of the plot. An FSI of 2 on a 1,000 square metre plot allows about 2,000 square metres of floor area, subject to the regulations. It is the single number that most determines whether a redevelopment is viable. In Mumbai, FSI rules are set by the Development Control and Promotion Regulations 2034 (DCPR 2034).
DCPR 2034. The Development Control and Promotion Regulations for Greater Mumbai, which set out FSI, setbacks, heights, parking, redevelopment schemes and much more. The '33 series' of regulations covers most redevelopment routes, such as cluster schemes under 33(9). If your society is considering redevelopment, the regulation that applies to your plot is the first thing your consultant should identify.
Fungible FSI (fungible compensatory area). Additional built-up area allowed over and above the admissible FSI, generally on payment of a premium to the municipal corporation. Under Regulation 31(3) of DCPR 2034, residential development can generally use up to 35 per cent additional fungible compensatory area, according to published summaries. It is often used for balconies, larger rooms and similar space.
TDR (Transferable Development Rights). Development rights that are generated when land is surrendered for a public purpose, or through certain redevelopment schemes, and that can be sold and used on another plot to build additional floor area. Developers buy TDR to increase what they can build. Self-redevelopment incentives in Maharashtra include concessions on TDR purchase, according to published summaries of the 2019 GR.
Incentive FSI. Additional floor area granted as an incentive for a particular kind of development, such as the redevelopment of old buildings, slum rehabilitation or cluster schemes. It is how the rules make redevelopment financially possible. A society's redevelopment offer often depends heavily on how much incentive FSI is available.
Premium. A payment to the planning authority for certain additional development rights, such as fungible area or some forms of additional FSI. Premiums are part of a redevelopment's cost and are one of the items on which self-redevelopment schemes receive concessions. Their amounts are set by the authorities and change over time.
Setback. The minimum distance a building must be kept from the plot boundary or the road. Setbacks leave space for light, air, access and fire engines, and they limit how much of a plot a new building can cover. They are one reason a redeveloped building is often taller rather than wider.
Approvals and certificates
IOD (Intimation of Disapproval). In Mumbai, the document the planning authority issues on a building proposal, listing the conditions that must be met before work can begin and at later stages. Despite the name, an IOD is effectively a conditional approval of the plans. Newer approval systems may use different terms, such as intimation of approval, but IOD remains common usage.
CC (Commencement Certificate). The permission to start construction. In Mumbai it is usually issued in stages, first up to plinth level and then extended for the upper floors as conditions are met. A buyer can ask to see the CC covering the floor on which their flat sits.
Plinth. The level at which the building's superstructure begins, just above the ground. A 'plinth CC' is the commencement certificate up to plinth level, and a further CC is needed to build above it. Plinth protection is the paving around a building that keeps water away from the foundations.
OC (Occupancy Certificate). The certificate from the planning authority confirming that a building has been built in line with the approved plans and is fit for occupation. Moving into a flat without an OC can create problems with utilities, loans, resale and legal standing. A part OC may be issued for some floors or wings of a larger project.
Completion Certificate (BCC). The certificate confirming that the building work is complete as per the approvals. It is sometimes called the Building Completion Certificate. In practice in Mumbai, buyers tend to focus on the OC, but both are part of a building's legal history.
NOC (No Objection Certificate). A letter from an authority or body confirming it has no objection to a proposed action. Construction projects need several, for example from the fire department. Within a housing society, members often need a society NOC before renovating their flats; our article on society NOC for flat renovation explains that process.
Property card. A land record maintained by the state's land records department for urban properties in Mumbai, showing ownership and area of the land. It is one of the title documents a society needs for conveyance and redevelopment.
Structural stability certificate. The certificate a registered structural engineer issues after examining a building. Under Section 353B of the Mumbai Municipal Corporation Act, buildings in use for more than 30 years must be examined and a certificate submitted, and renewed every ten years. Our explainer on the BMC's C1, C2A, C2B and C3 categories covers what happens after an audit.
MahaRERA and buyer protection
RERA. The Real Estate (Regulation and Development) Act, 2016, the national law regulating real estate projects and agents. It requires eligible projects to be registered, sales to be made on carpet area, and developers to follow rules on disclosure, use of buyers' money and defect liability. Each state has its own regulatory authority under the Act.
MahaRERA. The Maharashtra Real Estate Regulatory Authority, which registers projects and agents in the state, publishes project details and hears complaints. Every registered project has a MahaRERA registration number, which you can look up on the MahaRERA website to check approvals, progress and the declared completion date.
MahaRERA registration number. The unique number given to a registered project, usually beginning with a letter P followed by digits. Tower 28 in Malad East, for example, carries MahaRERA number P51800009511. Advertisements for registered projects must display it, and it is the quickest way to check what a developer has declared.
Agreement for sale. The registered agreement between a buyer and a developer that sets out the flat, the carpet area, the price, the payment schedule, the possession date, the specifications and each side's obligations. Under RERA, the terms must be consistent with the model form prescribed. Read the specification schedule carefully; it is what the finished flat will be measured against.
Possession date. The date by which the developer has committed to hand over the flat, as declared to MahaRERA and in the agreement. Delays beyond the committed date can give buyers remedies under RERA. Possession is also when the defect liability period generally begins.
Defect liability period. Under RERA, if a structural defect, a defect in workmanship, quality or provision of services, or any other breach of obligations is brought to the developer's notice within five years of possession, the developer must rectify it without further charge, within the time the law provides. Most defects buyers report in practice relate to finishing: seepage, hollow tiles, poor drainage and window leakage.
QAC (Quality Assurance Certificate). MahaRERA's quality-assurance framework expects developers to assess and certify the quality of their construction during a project, covering materials, workmanship and safety. Because it is published, it becomes a record buyers can read. Our article on MahaRERA's quality assurance certificate explains what it means for the finishing phase.
Sample flat. A furnished show flat that a developer builds to demonstrate the finished product. It is marketing, not a specification. A buyer or society should rely on the written specification in the agreement, not on 'as per sample flat'.
Redevelopment and housing society terms
Redevelopment. The demolition of an old building and construction of a new one on the same land, with existing residents rehoused in the new building and additional flats sold to fund the work. According to the JLL and NAREDCO Maharashtra report released on 3 September 2026, more than 1,000 redevelopment projects have been launched in Mumbai since 2020.
Self-redevelopment. Redevelopment in which the housing society acts as its own developer, arranging finance, appointing consultants and contractors and selling the additional flats. Maharashtra has supported it since a Government Resolution of 13 September 2019. Our self-redevelopment guide explains the process and risks.
Cluster redevelopment. The redevelopment of a group of buildings or an entire colony as one planned scheme, rather than one building at a time. In Greater Mumbai it is governed mainly by Regulation 33(9) of DCPR 2034. Our cluster redevelopment explainer compares it with standalone redevelopment.
PMC (Project Management Consultant). A consultant, often an architect-led firm, appointed by a society to advise on and manage redevelopment: feasibility, tender, approvals and supervision. In self-redevelopment the PMC is central. In builder-led redevelopment a PMC protects the society's interests against the developer's.
Feasibility report. A study of whether and how a redevelopment can work: the plot's development potential, members' entitlements, the number of sale flats, costs, finance and the resulting offer to members. It should be prepared before a society compares developer offers or chooses self-redevelopment.
Development agreement. The agreement between a society and a developer setting out the terms of a redevelopment: what members receive, rent, timelines, specifications, obligations and remedies. It is the society's main point of leverage, which is why the finishing specification should be written into it.
PAAA (Permanent Alternate Accommodation Agreement). The individual agreement between each member and the developer, or the society in self-redevelopment, confirming the new flat the member will receive in place of the old one, with its area, floor and other terms. It is a key document for each member's rights.
Corpus fund. A lump sum a developer pays to a society or its members in a redevelopment, often intended to help with the higher maintenance costs of a taller building with lifts, pumps and more common areas. Its amount and use are negotiated in the development agreement.
Rehab component and sale component. In a redevelopment or SRA scheme, the rehab component is the housing for existing residents, and the sale component is the housing sold on the open market to fund the project. In Tower 28, Malad East, the four sale wings are the sale component of the Navjeevan SRA scheme, with separate rehabilitation buildings for existing residents.
SRA (Slum Rehabilitation Authority). The authority, formed in 1995, that oversees slum rehabilitation schemes in Mumbai, where eligible slum dwellers are rehoused in new buildings and the developer is compensated with sale area. Our published projects include SRA schemes in Malad East and Kandivali West.
Cessed building. An old building, mostly in the island city, for which the state collects a repair cess, and for whose repair and reconstruction MHADA's Mumbai Building Repairs and Reconstruction Board is responsible. The JLL and NAREDCO Maharashtra report counts around 13,500 cessed buildings needing replacement.
C1, C2A, C2B, C3. The categories used to classify old buildings after structural assessment. C1 is dangerous and must be vacated and demolished; C2A needs major repairs with the dangerous part vacated; C2B needs major repairs without vacating; C3 needs minor repairs. Our explainer covers them in detail.
Conveyance and deemed conveyance. Conveyance is the transfer of ownership of the land and building from the developer to the housing society. Where a developer fails to execute it, a society can apply to the competent authority for deemed conveyance. A society without conveyance may find redevelopment and financing harder.
Sinking fund and repair fund. Funds a housing society keeps for the eventual reconstruction of the building and for repairs and maintenance. The Maharashtra Co-operative Societies (Amendment) Rules, 2026, set minimum annual contributions to both, according to published summaries; our article on the 2026 housing society rules explains them.
Transit accommodation. Temporary housing provided to residents during a redevelopment, either as rent paid to members to find their own homes or as flats in transit camps. How long it lasts and what happens if the project overruns are among the most important terms in any redevelopment agreement.
The building structure
RCC (Reinforced Cement Concrete). Concrete with steel reinforcement bars cast inside it, so that the concrete resists compression and the steel resists tension. Almost every modern Mumbai building has an RCC frame of columns, beams and slabs. When a contractor says the 'RCC is ready', they mean the frame is complete and finishing work can begin.
Column, beam and slab. Columns are the vertical members that carry loads down to the foundations. Beams are the horizontal members that carry slabs and walls to the columns. Slabs are the floors and roofs. None of them should ever be cut, chased or drilled heavily during a renovation without a structural engineer's approval.
Shear wall. A reinforced concrete wall designed to resist sideways forces such as wind and earthquakes, common in taller buildings. Shear walls look like ordinary walls once plastered, which is why a renovation that plans to break a wall must first confirm from the drawings whether it is structural.
Stilt and podium. A stilt floor is an open ground floor, supported on columns, typically used for parking. A podium is one or more levels of structure, often parking and amenities, on which residential towers stand. 'Stilt plus eight', for example, means an open stilt floor with eight residential floors above.
Refuge area. An open or semi-open floor area kept free in high-rise buildings, at intervals set by fire and building regulations, where occupants can gather safely during a fire. It must remain unobstructed and cannot be enclosed or used for storage or living space.
Lintel. A short beam over a door or window opening that carries the wall above. Cracks at the corners of openings often run from the ends of lintels. In a renovation, widening an opening means changing or adding a lintel, which should be designed rather than improvised.
Chajja. A projecting concrete sunshade or weather shade over a window, common on older Mumbai buildings. Chajjas throw rain away from the window, but on old buildings they are also a common site of corrosion and spalling concrete, and a frequent item in structural audit reports.
Parapet. The low wall around the edge of a terrace or roof. The junction between the terrace floor and the parapet is one of the places terrace waterproofing most often fails, because water collects there and the waterproofing has to turn up the wall and be protected.
Downtake. The vertical drainage pipe that carries water from terraces, balconies, bathrooms and kitchens down the building. Leaking or cracked downtakes are a major cause of seepage into walls, and on older buildings they are often the first thing to check when damp appears.
Finishing work terms
Finishing work. Everything that happens after the RCC structure is ready to turn it into homes: waterproofing, plumbing and electrical routing, flooring, tiling, dado, kitchens, bathrooms, windows, lobbies, staircases and snagging. It usually takes as long as the structure did. Our article on what finishing work in construction includes covers the full scope.
Coba. A traditional terrace waterproofing layer in Mumbai, made of broken brickbat laid in lime or cement mortar to a slope, finished with a smooth surface often marked in a grid. It provides a fall to drain water and some protection, but on its own it is not a modern waterproofing membrane, and old coba that has cracked is a frequent cause of top-floor leaks. Our terrace waterproofing article explains when it should be replaced.
Screed. A levelling layer of cement and sand mortar laid over a slab to create a flat or sloped surface for the final floor finish. In bathrooms and balconies, the screed carries the fall that takes water to the drain. Plumbing should be run and tested before the screed is laid, not after.
IPS (Indian Patent Stone). A floor finish of cement concrete laid in panels and finished smooth, often used in parking areas, utility spaces and as a base. The term is also used loosely for a cement concrete topping. It is hard-wearing but plain, and it is usually covered by tiles in living areas.
Waterproofing membrane. A continuous layer, applied as a liquid coating, cementitious system or sheet, that stops water passing through a floor, wall or roof. In bathrooms it should cover the floor and turn up the walls to an adequate height; on terraces it must be protected from sunlight and damage. Most seepage problems come from gaps at corners, pipes and drains.
Ponding test. A simple test of waterproofing: the drain is plugged, the area is flooded with water to a set depth and left, typically for a day or more, and the ceiling below is checked for leaks. It should be done before tiles or screed cover the waterproofing. Our article on bathroom waterproofing mistakes explains why skipping it is costly.
Fall or slope. The deliberate slope built into a wet floor so water runs to the drain. A bathroom floor without a proper fall holds puddles, which is one of the most common defects in new flats. It is set in the screed and cannot be corrected without lifting the tiles.
Dado. Wall tiling or cladding applied up to a certain height, most often in kitchens and bathrooms, to protect walls from water and stains. Full-height dado runs to the ceiling. Our dado and wall cladding guide covers materials, heights and fixing.
Skirting. A narrow strip of tile, stone or wood along the base of a wall where it meets the floor, protecting the wall from cleaning and knocks. It should line up with the floor tile joints where possible. Poorly fixed skirting is an easy snagging item to spot.
Vitrified tile. A ceramic tile fired at high temperature so that it absorbs very little water, making it hard-wearing and stain-resistant. It is the most common flooring in Mumbai flats. Our guide to choosing floor tiles compares it with marble, granite and other options.
Kota stone. A fine-grained limestone from Rajasthan, used for floors, staircases, parking areas and utility spaces. It is durable and slip-resistant, usually grey-green or brown, and can be polished. It is common on older Mumbai staircases and landings.
Granite and marble. Natural stones used for kitchen platforms, staircases, lobbies and flooring. Granite is hard and resists staining and scratching well, which makes it the usual choice for kitchen counters. Marble is softer and more porous and reacts with acids, so it needs more care.
Grout. The material that fills the joints between tiles. It seals the joints and holds the tile edges. Cement-based grout is common; epoxy grout is more resistant to water and staining, and is often recommended in wet areas. Cracked or missing grout lets water behind tiles.
Hollow tile. A tile that sounds hollow when tapped because there is a void beneath it, usually because it was bedded on dabs of mortar rather than a full bed. Hollow tiles crack under load and cannot be fixed without lifting them. Tapping every tile is part of a proper snagging inspection.
POP (Plaster of Paris) and gypsum. Materials used for smooth wall and ceiling finishes and for false ceilings and decorative work. POP punning over plaster gives a smooth surface for paint. POP and gypsum do not tolerate water, so persistent damp behind them shows up as bubbling and flaking.
Wall putty. A fine filler applied over plaster before painting to fill small imperfections and give a smooth surface. It is a standard part of good internal painting. Like POP, it fails where walls are damp, which is why seepage must be fixed before repainting.
Concealed plumbing and concealed wiring. Pipes and electrical conduits run inside walls and floors rather than on the surface. They look cleaner, but once they are closed in, faults are hard to reach. They should be pressure tested or checked before plastering and tiling, and their routes recorded.
Tread, riser and nosing. On a staircase, the tread is the horizontal part you step on, the riser is the vertical face between treads, and the nosing is the front edge of the tread. Unequal riser heights on a single flight are a trip hazard. Our staircase finishing article explains how they should be set out.
Window sill. The horizontal surface at the bottom of a window opening, inside and outside. An external sill should slope outwards and have a drip edge so rain is thrown clear of the wall. Poorly detailed sills are a common source of water entering around windows.
Snagging. The inspection of a finished flat to find and record defects before handover, followed by their rectification. A snag list covers everything from hollow tiles and poor falls to paint defects and doors that bind. Our new flat snagging checklist gives a room-by-room list you can use.
Hold point. A stage in construction at which work must stop until the previous step has been inspected and approved, for example waterproofing tested before it is covered or plumbing tested before it is concealed. Hold points are how good finishing contractors make quality visible and recorded rather than assumed.
Why the vocabulary matters
Knowing these terms does not make anyone a builder, but it changes the conversation. A buyer who asks for the carpet area, the OC and the waterproofing method is harder to mislead than one who asks only about the view. A society member who knows what a PAAA, a corpus fund and a ponding test are will ask better questions before signing. A homeowner who knows what a shear wall is will think twice before letting a contractor break one.
Most of the problems we are called in to fix in Mumbai flats come down to words that were never checked: 'as per sample flat', 'waterproofing done', 'tiles laid'. Each hides a method, and the method is what decides whether the finish lasts.
Ask us about any term
Chamunda Constructions has carried out finishing work for Mumbai builders since 2004, and home renovation and society repair work across Kandivali, Malad, Borivali, Andheri, Mulund and beyond. If a term in your agreement, your structural audit or your contractor's quotation is not clear, or you want someone to walk your flat or building and explain what they see, Bhadresh Chavda is happy to visit.