How Common Areas Are Calculated for NKDA Occupancy Certificate in Group Housing
How common area gets calculated for an NKDA occupancy certificate in a group housing project is a question we get from two different kinds of people almost every month, developers and design teams preparing the completion drawings that will actually go in front of NKDA, and buyers who already own a flat and are trying to work out why their maintenance bill is calculated against a super built-up figure that seems to include far more square footage than their flat's own walls would suggest. The honest answer is that common area for occupancy certificate purposes is not one single number NKDA pulls from thin air, it is a specific list of spaces, lobbies, stairwells, lift shafts, corridors, and a handful of service areas, that get measured individually on the completion drawings and added together, and the confusion buyers run into almost always traces back to a developer's marketing brochure using a broader definition of common area than the one NKDA actually certifies against.
What NKDA Actually Counts as Common Area at OC Stage
When NKDA reviews a group housing project for occupancy certificate, it works from the sanctioned drawings and the as-built measurement together, and the common area figure it certifies is built from a defined set of categories rather than a blanket percentage applied to the whole plot. Entrance lobbies and reception areas at the ground floor, internal corridors on every residential floor that connect individual flat entrances to the staircase or lift core, staircases themselves including the landing areas at each floor, lift shafts and lift lobbies on every floor the lift serves, and service areas like the electrical panel room, the pump room, and the fire-fighting equipment room where these are shared across the block, all get measured and counted as common area in the completion drawings NKDA reviews. Open-to-sky areas like the internal courtyard or the podium garden in a multi-block development are treated separately from covered common area for most calculation purposes, and get their own line under the mandatory open space requirement rather than being folded into the same common area figure, which is a distinction worth knowing if you are comparing two projects' stated common area percentages against each other.
Lobby, Stairwell, and Lift Shaft: The Three Categories Buyers Ask About Most
Ground floor lobbies tend to be the single largest common area line item in most group housing projects we have worked on, because a well-proportioned entrance lobby in a New Town block of thirty to forty flats commonly runs anywhere from 400 to 900 square feet depending on the block's overall scale, and that entire footprint counts toward common area regardless of how much of it is finished with reception furniture versus left as circulation space. Stairwells count on every floor they physically occupy, so a ten-storey block effectively multiplies the stairwell's floor-plate footprint by ten when the total common area is added up, even though a resident only actually uses the staircase for a few seconds crossing each landing, which is part of why taller blocks generally show a higher common area percentage than a low-rise block of similar total built-up area. Lift shafts and their associated lobbies work the same way, counted per floor across the full height the lift travels, and a project running two lifts rather than one will show a meaningfully larger common area total purely from the second shaft and its floor-by-floor lobby space, independent of whether the second lift genuinely gets used at capacity.
| Common Area Category | Counted Per | Typical Range in a Mid-Rise New Town Block | |||
|---|---|---|---|---|---|
| Ground floor lobby | Once | at entry level | 400-900 sq ft | ||
| Staircase and landings | Every floor served | 60-120 sq ft per floor | |||
| Lift shaft and lobby (per lift) | Every floor served | 40-80 sq ft per floor | |||
| Corridor connecting flats | Every residential floor | 80-200 sq ft per floor | |||
| Service rooms (pump | panel | fire) | Once | typically ground or basement | 150-400 sq ft total |
Where the Terrace Fits, and Why It Is Not a Simple Yes or No
The terrace is the single most disputed line item in almost every group housing common area conversation we sit in on, because whether it counts as common area for OC purposes, and by extension whether it becomes part of every owner's shared maintenance liability, depends on how the terrace is actually treated in the sanctioned plan rather than on a fixed rule that applies the same way to every building. A terrace kept genuinely open and accessible to all owners, used for the overhead water tank, solar arrangements, or simply as shared open space, is generally treated as common area and counted in the OC common area figure, while a terrace that has been earmarked in the sanctioned drawings for an exclusive top-floor unit, sometimes with a separate access door and a documented terrace rights clause in that unit's sale agreement, is excluded from the shared common area calculation and effectively belongs to that flat instead. This is precisely the kind of clause we tell buyers to check directly in the sale agreement and the sanctioned plan rather than relying on a builder's verbal assurance, because a terrace that reads as common space in a brochure can turn out to be legally reserved for one unit once the actual documents are compared.
Why This Number Matters Beyond the Certificate Itself
The common area figure NKDA certifies at occupancy stage does more than satisfy a regulatory checkbox, because it becomes the basis for how maintenance charges are apportioned among owners, how the residents' association calculates its corpus fund contributions, and in many cases how the gap between a flat's carpet area and its super built-up area gets explained to a buyer at the point of sale. A project where the common area works out to a high percentage of the total super built-up figure, sometimes running toward the upper end of what is typical for a taller block with two lift cores and generous lobbies, is not necessarily a red flag on its own, but it does mean each owner's per-square-foot cost effectively covers more shared space, so it is worth understanding the split before comparing the price of two projects purely on their advertised super built-up rate. NKDA's completion certificate process, outlined on NKDA's own portal, requires the common area breakdown to be part of the as-built measurement submitted for OC, which is exactly the document a diligent buyer or an incoming residents' association should be asking to see rather than relying on secondhand figures.
- Ask for the NKDA-certified common area figure from the occupancy certificate, not the sales brochure
- Confirm whether the terrace is shared common area or reserved for a specific unit in the sanctioned plan
- Check how many lift cores the block runs and whether both are counted in your maintenance apportionment
- Verify that service rooms like the pump room and fire panel room are included once, not duplicated across floors
- Compare the common area percentage against similar-scale projects before judging it as high or low
How We Handle This on the Design Side
On projects where we are involved from the design stage rather than being brought in after handover, we build the common area schedule into the drawings from the first floor plan rather than reconciling it after the fact, because a lobby, stairwell, or lift core that grows during design revisions has a direct knock-on effect on every future owner's maintenance share, and getting the schedule right early avoids the awkward conversation of explaining a shifted common area percentage to buyers who signed on an earlier brochure figure. For a deeper look at what group housing sanction actually involves once the drawings move from design to submission, our related post on the NKDA occupancy certificate process walks through the stages in more detail, and if your question is really about what happens after occupancy when an owner wants to change how a unit within the building is used, our piece on converting a residential building into a PG or hostel under KMC rules covers a related but distinct approval track. We also maintain a shorter internal reference currently published as Test where smaller clarifications on figures like these get logged as they shift.
Talk to Us Before You Sign Off on a Common Area Figure
Whether you are a developer preparing completion drawings, a residents' association trying to reconcile a maintenance bill against the actual occupancy certificate, or a buyer comparing two projects' common area percentages before booking, the underlying calculation is knowable rather than opaque once you know which categories NKDA is actually measuring. If you want a second set of eyes on a common area schedule, a sanctioned plan, or a maintenance apportionment that does not seem to add up, bring the documents to us through our contact page and we will go through the numbers with you line by line.