Cost guide · Updated October 2026
Home extension and renovation costs in Chennai & Bengaluru
What it typically costs to add a floor, build a terrace room or a room over the car porch, and renovate an independent house — per square foot, with worked examples and the costs that are easy to miss. Every number on this page is a range; your exact figure comes from a survey of your house.
Extension costs per sq ft
For new built-up area with standard finishes — tiled floors, painted walls, electrical and plumbing, windows and doors — on an independent house. Ranges include materials, labour and GST.
| Work | Chennai | Bengaluru |
|---|---|---|
| Add a floor — RCCBrick or block walls, concrete slab | ₹2,200–₹3,200 | ₹2,400–₹3,400 |
| Add a floor — light gauge steelSteel frame, insulated walls | ₹2,000–₹3,000 | ₹2,100–₹3,100 |
| Terrace room — insulated steelBedroom or office standard | ₹1,700–₹2,800 | ₹1,800–₹2,900 |
| Room over the car porchBefore any strengthening of porch columns | ₹1,900–₹3,000 | ₹2,000–₹3,100 |
| Sheet-roof enclosureUtility or storage only | ₹900–₹1,500 | ₹950–₹1,600 |
The low end of each range is a simple layout with standard tiles and fittings; the high end is more glazing, more bathrooms, premium flooring and more complex structure. Bengaluru is a little higher mainly because of labour.
Renovation costs per sq ft
| Work | Chennai | Bengaluru |
|---|---|---|
| RefreshPainting, repairs, new fittings | ₹350–₹700 | ₹400–₹750 |
| StandardFloors, rewiring, plumbing, kitchen, bathrooms | ₹1,000–₹1,800 | ₹1,100–₹1,900 |
| MajorLayout changes, structural repair, premium finishes | ₹1,800–₹3,000 | ₹1,900–₹3,200 |
| Work | Typical cost |
|---|---|
| KitchenMid-range modular, including tiling and services | ₹2–6 lakh |
| BathroomPer bathroom, full redo | ₹1.5–3.5 lakh |
| FlooringVitrified tile, old floor removed | ₹120–₹250 / sq ft |
| Interior paintingPer sq ft of wall area | ₹18–₹35 / sq ft |
| Terrace waterproofing | ₹60–₹150 / sq ft |
| RewiringPer sq ft of built-up area | ₹80–₹150 / sq ft |
| Plumbing replacementPer sq ft of built-up area | ₹70–₹140 / sq ft |
Read more in our guides to renovation in Chennai and Bengaluru.
Costs people forget
| Work | Typical cost |
|---|---|
| Architecture and structural designPer sq ft of new area | ₹60–₹150 / sq ft |
| Column jacketingPer column, if needed | ₹25,000–₹60,000 |
| Foundation strengtheningTypical G+1 house, if needed | ₹2–6 lakh |
| Laboratory concrete testsOnly if the free check shows they are needed | ₹15,000–₹40,000 |
| Waterproofing the old terraceBefore building on it | ₹60–₹150 / sq ft |
- Approval fees are set by the local body and depend on your plot and the area added.
- Extending services: a new staircase flight, a bigger water tank, a separate electricity meter for a rental floor.
- Living elsewhere during a major renovation, if the house cannot stay usable.
- A contingency of 10–15% for what is found behind plaster and under floors in an older house.
Worked examples
A new 900 sq ft floor in Chennai
Construction in RCC: ₹19.8–28.8 lakh. In light gauge steel: ₹18–27 lakh. Design at ₹60–₹150 per sq ft adds ₹54,000–₹1,35,000. If four columns need jacketing, add ₹1–2.4 lakh. Read the full guide to adding a floor.
A 220 sq ft terrace room with a bathroom in Bengaluru
Room: ₹4–6.4 lakh. Waterproofing 600 sq ft of open terrace around it: ₹36,000–₹90,000. See terrace room construction.
A standard renovation of a 1,200 sq ft house in Chennai
New floors, rewiring, plumbing, a kitchen and two bathrooms: ₹12–21.6 lakh.
What moves the price
- Structure: how much strengthening the existing house needs, and RCC versus steel.
- Wet areas: each bathroom or kitchen adds plumbing, waterproofing and tiling.
- Glazing: large windows and sliding doors cost more than walls.
- Finishes: the jump from standard to premium tiles, fittings and joinery.
- Access: narrow roads and no space to store material slow the work down.
- Timing: roof and external work in the monsoon takes longer and risks damage.
How you will pay
Payments are usually staged against work done: a booking amount when design starts, then instalments as structure, walls and roof, services and finishes are completed, with a final payment at handover. Avoid paying a large share up front. The free feasibility check gives you an early cost range before you commit to anything; a detailed estimate follows the design.
Questions people ask
What is the cost per sq ft to add a floor in Chennai?
About ₹2,200–₹3,200 per sq ft for RCC and ₹2,000–₹3,000 for light gauge steel, with standard finishes. Strengthening, design and approvals are extra.
Is a steel extension cheaper than RCC?
Per square foot, a light gauge steel floor usually costs slightly less than RCC, but the bigger saving is often elsewhere: because it is lighter, the existing house may need less strengthening, and it is finished in weeks rather than months.
Do these prices include GST?
Yes. The ranges include materials, labour and GST. They do not include loose furniture, appliances, government approval fees or strengthening the existing structure, which are listed separately.
Why do quotes for the same extension vary so much?
Quotes differ in what they include — finishes, bathrooms, waterproofing of the old roof, electrical work, strengthening, design and approvals. Compare itemised estimates with the same specification, not headline rates per square foot.
How much should I keep aside for surprises?
Keep 10 to 15 percent of the construction cost as a contingency for an extension or renovation of an older house. Hidden damage behind plaster, under floors or in the roof is common.
Get a cost range for your house.
Free site visit and structural check — you get an early range before you spend anything on design.