Estimates, Worked Examples and Checklists
Repair or replace a roof in India: how to decide, with cost examples
When a leaking terrace or sheet roof in India can be repaired and when it needs full replacement, with signs to check, illustrative cost comparisons and financing.
A roof can usually be repaired when the leak has a clear, local cause (a cracked joint, a failed drain collar, a few damaged sheets, a worn patch of coating) and the structure underneath is sound. It usually needs replacement when the waterproofing or sheets have failed across much of the area, the old layers hold water, the frame or slab shows corrosion or sagging, or repeated repairs have not worked. Cost alone is a poor guide: a cheap patch on a roof that is failing everywhere is often paid for twice. The comparisons below use illustrative figures to show how to weigh the choice over several years.
Part of how to read a roofing or façade quotation.
Signs that point to repair or to replacement
| What you see | Leans to repair | Leans to replacement |
|---|---|---|
| One damp patch, near a drain, pipe or parapet corner | Yes | |
| Damp patches in many places across the ceiling | Yes | |
| Coating worn in places, sound elsewhere | Yes (recoat) | |
| Coating peeling or blistering over large areas | Yes | |
| Brickbat coba sounding hollow and holding water | Yes | |
| A few broken or loose roof sheets | Yes | |
| Rust holes in many sheets, or corroded purlins | Yes | |
| Sagging slab, wide or growing cracks, exposed rusting steel | Structural engineer first | |
| Leak started after other work (solar mounts, dish, AC) | Yes, fix the penetration |
First, be sure where the water comes from
Many "roof leaks" are not. Water can come from a leaking pipe in the slab, an overflowing tank, a bathroom above, a gap at a window or a damp wall. Before you pay for a new roof, trace the source: check where the damp appears relative to drains and pipes, whether it appears only during rain, and whether it gets worse with tank filling. A leak investigation, by a specialist if needed, costs much less than the wrong repair.
Cost comparison over time: terrace (illustrative)
A 1,000 sq ft terrace with an ageing coating and one leak at a drain.
Option 1: repair and recoat now
- Fix the drain collar and nearby cracks: ₹8,000
- Clean and apply two coats of elastomeric coating over the whole area at ₹45 per sq ft: ₹45,000
- Subtotal ₹53,000; with 18% GST ₹62,540
- Recoat again in, say, 4 years at a similar cost (in today's money): ₹62,540
- Two rounds over 8 years: ₹1,25,080
Option 2: break out and replace with a PU system now
- Breaking out and slope correction: ₹30,000
- PU membrane at ₹110 per sq ft: ₹1,10,000
- Protective screed or tiles on top: ₹60,000
- Subtotal ₹2,00,000; with 18% GST ₹2,36,000 once
In this illustrative case, repair and recoat is cheaper over 8 years if the slab and old layers are sound. If the old brickbat coba is hollow and wet, the coating will fail early, and Option 1 can turn into Option 1 plus Option 2. The deciding factor is the condition under the surface, which is why a tap test and a core or opening at a suspect spot are worth asking for.
Cost comparison: sheet roof (illustrative)
An 800 sq ft sloping sheet roof with five damaged sheets and rusty fasteners.
| Repair | Replace sheets only | Replace sheets and frame | |
|---|---|---|---|
| Work | Replace 5 sheets, re-fix with new screws and washers, reseal ridge | New sheets on existing frame | New sheets and steel structure |
| Illustrative cost before GST | ₹25,000 | ₹1,05,000 | ₹2,20,000 |
| With GST 18% | ₹29,500 | ₹1,23,900 | ₹2,59,600 |
| Makes sense when | Frame sound, other sheets in good condition | Frame sound, sheets widely corroded | Frame corroded or undersized for wind |
See the metal roof replacement worked example for how these totals are built.
Paying for a replacement
A replacement can be a large one-off bill. Options include savings, a home improvement loan or a top-up on an existing home loan (often cheaper because they are secured), a personal loan, or a card EMI. As an illustration, ₹2,00,000 borrowed at 11% a year for 2 years gives an EMI of about ₹9,322 and interest of about ₹23,700, before fees. At 16% the EMI would be about ₹9,793 and interest about ₹35,000. Compare offers in the repair loan EMI calculator, and read the Key Facts Statement for the annual percentage rate and charges.
Insurance: does it change the decision?
If a storm, cyclone or flood damaged the roof, a home insurance policy may pay for repair or replacement of the damaged part, subject to its terms. Gradual wear, old leaks and poor maintenance are generally excluded. Report the damage before you repair, except for urgent temporary measures. See home insurance for storm and flood damage.
A simple decision routine
- Trace the source of the leak.
- Inspect the structure; call a structural engineer if you see sagging, wide cracks or rusting steel.
- Get at least two quotations: one for repair, one for replacement, each itemised.
- Compare cost over several years, not just today's bill.
- Check whether insurance applies.
- Put the chosen scope in writing with a warranty; see the contract and warranty checklist.
FAQ
How many times can a terrace be recoated?
Many liquid coatings can be recoated if the existing layer is well bonded and clean. Once layers are peeling or the substrate is wet, recoating stops working.
Is a waterproofing "patch" worth doing before the monsoon?
As a temporary measure to limit damage, yes, if it is described honestly as temporary. Plan the proper repair for the dry season.
Does replacing the roof add value to the house?
It protects the structure and avoids damage inside. Whether it raises the sale price is a market question we cannot answer.
Should I replace the roof before installing solar panels?
If the roof is near the end of its life, doing roof work first avoids removing and refitting the panels later.
Sources and where to check
- Bureau of Indian Standards — National Building Code and product standards
- Reserve Bank of India — Key Facts Statement and fair practices for loans
- IRDAI — home insurance and policyholder protection
