What building plan sanction is
Before you start construction on a plot, the local municipal or planning authority typically needs to approve your building drawings. In Bengaluru this is usually BBMP (or the relevant authority such as BDA or a local planning body, depending on where your plot falls). This approval is commonly called a "building plan sanction" or "building licence".
The authority checks whether your proposed building follows local building bye-laws — things like how much of the plot you can build on (broadly captured by FAR / FSI), how far the building must sit from the plot edges (setbacks), permitted height, and the number of floors. These rules vary by city, zone, plot size and road width, so two nearby plots can have quite different limits.
The exact rules, fees and documents differ by local authority and change over time. Treat this article as a general map, not a rulebook — confirm the current requirements with your local body or a licensed architect or engineer before you rely on any specific number.
The sanctioned plan — your most important drawing
When the authority approves your drawings, it issues a stamped or digitally approved set known as the "sanctioned plan". This is the legally recognised version of what you are allowed to build. Everything on site is meant to match it — footprint, setbacks, number of floors and overall dimensions.
Keep the sanctioned plan safe. It is typically asked for later when you seek a completion or occupancy certificate, apply for water and electricity connections, sell or mortgage the property, or update municipal records. A bank considering a home loan on the property will often want to see it too.
If you later change the design during construction — an extra floor, a larger footprint, covering a setback — the building may no longer match the sanctioned plan. That "deviation" is a common source of problems, and in many cases it needs a revised sanction. When in doubt, check with your architect and local body before deviating.
The general flow, and why unapproved building is risky
The typical sequence looks like this: a licensed architect or engineer prepares drawings that respect local bye-laws; you (or your professional, on your behalf) submit them to the local authority along with proof of ownership, tax and title documents; the authority reviews and, if satisfied, issues the sanctioned plan; construction then proceeds in line with that plan; and at the end you apply for a completion and/or occupancy certificate. Many cities now run parts of this online, and steps and names differ from place to place.
Building without sanction — or building beyond what was sanctioned — carries real risk. Depending on the local authority, unapproved or deviated construction can attract penalties, notices, difficulty getting water and power connections, trouble selling or getting a loan, and in serious cases demolition of the unauthorised portion. Regularisation schemes appear from time to time but are not guaranteed and should never be assumed.
Because consequences and processes vary widely by state and city, the safe path is to engage a licensed professional early and confirm every requirement with your local authority. This article is general guidance, not legal advice.
Frequently asked
Do I always need plan sanction to build?
What happens if I build differently from the sanctioned plan?
Who usually prepares and submits the drawings?
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