Bangalore has two very different kinds of duplex. There's the new builder duplex in a gated project off Sarjapur or Hennur, handed over with sound wiring and a predictable layout. And there's the older independent house in Jayanagar, Basavanagudi, Malleshwaram or RT Nagar, often thirty or forty years old, built floor by floor as the family grew, with plumbing and wiring that reflect every one of those decades.
The interior cost for those two can differ by 40 per cent for the same floor area, and almost all of the difference is in work you'll never see.
Here's what duplex and independent house interiors actually cost in Bangalore in 2026.
Headline costs
For a duplex or independent house of 1,800 to 2,800 sq ft built-up area:
A newer building with sound services, mid-range finishes throughout: Rs 22 lakh to Rs 38 lakh.
An older independent house needing rewiring, plumbing replacement and bathroom waterproofing, same finish level: Rs 32 lakh to Rs 52 lakh.
Upper mid-range in either case, with more extensive ceiling work, a designed staircase and wall panelling: Rs 45 lakh to Rs 70 lakh.
The gap between the first two figures is the point of this article. It's roughly Rs 10 lakh to Rs 14 lakh of invisible work, and discovering it in week three of a project is how duplex renovations go badly wrong.
What the older independent house actually needs
Electrical rewiring is the biggest single item, Rs 2.5 lakh to Rs 5 lakh for a full house. Wiring from the 1980s and 90s was sized for a fraction of the load a modern household runs. Extending old circuits rather than replacing them is a false economy and, with multiple ACs and a modern kitchen, a genuine safety question.
Plumbing replacement runs Rs 1.5 lakh to Rs 3.5 lakh. Galvanised iron lines corrode from the inside and reduce flow long before they leak. If the house has never been replumbed and you're opening walls anyway, do it now.
Bathroom waterproofing and reconstruction runs Rs 1.6 lakh to Rs 3 lakh per bathroom for a strip-to-slab redo. In a two-bathroom house that's Rs 3.2 lakh to Rs 6 lakh, and in an older independent house it's rarely optional, because a leaking upper bathroom in a duplex damages the room directly below.
Structural and civil corrections run Rs 1 lakh to Rs 4 lakh. Older houses accumulate additions with uneven floor levels, doorways at odd heights, and walls that aren't quite plumb. Some of this can be designed around; some has to be corrected.
Terrace waterproofing runs Rs 40 to Rs 80 per square foot and is almost always needed.
The staircase
In a duplex, the staircase is the one element every visitor sees and the one most likely to be left as-is because it's "structural." The structure usually is fixed, but everything attached to it isn't.
Replacing a builder railing with a designed one (MS and wood, or glass with a slim handrail) and cladding the treads in stone or engineered wood runs Rs 2.5 lakh to Rs 8 lakh depending on the run length and material.
The space under the staircase is the most under-used volume in most Bangalore duplexes. Built out properly it becomes a powder room (Rs 1.2 lakh to Rs 2.5 lakh), a home office nook (Rs 60,000 to Rs 1.4 lakh), or simply deep storage (Rs 40,000 to Rs 90,000). In a house where storage is always short, this is among the best-value square footage available.
Staircase lighting is worth its own line. Step lights or a wall-wash along the run cost Rs 25,000 to Rs 70,000 and transform how the stair reads at night, as well as making it safer.
Get an itemised estimate for your home.
Planning floor by floor
The one structural advantage a duplex has over a flat is that the floors are genuinely separable, which changes both the design and the project management.
The usual Bangalore convention places the living, dining, kitchen and one bedroom on the ground floor, with the remaining bedrooms and often a family lounge above. That's worth keeping unless you have a strong reason otherwise, because it means the house still works if someone in the household can't manage stairs.
Design the upper landing as a room, not a corridor. In most duplexes it's dead space. A reading nook, a study desk, or a compact family lounge there adds usable area for very little money.
Plan for sound. Footfall on an upper floor is audible below, particularly with vitrified tile or wooden flooring on a concrete slab. Carpet or a rug in the upper corridor, and attention to the ceiling below the most-used rooms, makes a noticeable difference in a house with children.
Phase the work by floor. Ground floor and kitchen first, upper floor second, is the sequence that lets a family stay in the house through the project if they need to. It adds two to three weeks overall but saves months of rent.
Where the money goes in a duplex, room by room
Modular kitchen, typically larger than a flat's at 12 to 16 feet of run: Rs 3 lakh to Rs 6.5 lakh.
Wardrobes across three to four bedrooms: Rs 3.5 lakh to Rs 7 lakh.
Living and dining false ceiling with lighting: Rs 2 lakh to Rs 4.5 lakh.
TV unit and feature wall: Rs 1 lakh to Rs 2.5 lakh.
Staircase treatment: Rs 2.5 lakh to Rs 8 lakh.
Full house electrical: Rs 1.5 lakh (newer) to Rs 5 lakh (rewiring).
Full house painting inside and out: Rs 1.8 lakh to Rs 4 lakh.
Flooring, if being replaced: Rs 120 to Rs 400 per square foot depending on material.
The survey that saves the budget
Before design starts on any independent house older than about fifteen years, we'd push hard for three checks.
An electrical load and wiring check by a licensed electrician, to establish whether you're extending or replacing.
A plumbing condition check, ideally including opening one wall section in a wet area to see what the lines actually look like.
A slab and terrace waterproofing check, especially above bathrooms and on the terrace.
Those three cost very little and turn the biggest unknown in the project into a line item you can budget for. Every duplex renovation that has gone badly over budget in our experience skipped at least one of them.
If you're weighing up an older Bangalore house, YellowDot Design Studio's free consultation includes that condition read before any design work starts.
Book a free consultation with YellowDot Design Studio. We'll do a condition read on wiring, plumbing and waterproofing before designing anything, so the number you plan against is the real one.
Find out what the house actually needs first