Estimates, Worked Examples and Checklists
How to read a roofing, waterproofing or façade quotation line by line
The line items to expect in a roof, terrace waterproofing, cladding or exterior painting quotation in India, red flags, and how to compare two contractors fairly.
A good roofing or façade quotation in India tells you what system will be used, on how many square feet, after what preparation, at what rate, with what GST, paid in which stages, and with what warranty. If any of these is missing, ask for it before you compare prices. Most "cheap" quotations are cheap because they leave something out: a coat, the parapet upturn, the removal of old layers, scaffolding or GST. Lining up two quotations item by item, on the same area and the same scope, is the single most useful thing you can do before you agree.
The line items to expect
| Line item | What it should say | Red flag |
|---|---|---|
| Scope | Which surfaces: terrace, parapets, sheds, walls, which faces of the building | "Complete waterproofing" with no surfaces listed |
| System and product | Product type and line, number of coats or layers, thickness or coverage | Only a brand name, or only "premium" |
| Preparation | Cleaning, scraping, crack repair, breaking out old layers, slope correction, primer | No preparation line at all |
| Area and measurement | Area in sq ft and how it will be measured at the end | Area "as per actual" with no method |
| Rate | Rate per sq ft for each system, and which items are lump sums | One lump sum for everything with no breakdown |
| Detailing | Drains, pipes, joints, tank stands, flashing, ridges, window reveals | Missing on a terrace with many pipes |
| Access | Scaffolding, rope access, lifting material | Added later as an "extra" |
| Debris and protection | Removal of debris, protection of tanks, plants, cars | Not mentioned |
| GST | Rate and amount, contractor's GSTIN | "Including all taxes" without an invoice promise |
| Payment schedule | Advance and stages linked to work done, and retention | Large advance before work starts |
| Timeline | Start date, duration, weather allowance | No dates |
| Warranty | Workmanship warranty period and what it covers; any manufacturer warranty | Verbal only |
Comparing two quotations: an illustrative example
Two contractors quote for the same 1,000 sq ft terrace.
| Contractor X | Contractor Y | |
|---|---|---|
| Headline rate | ₹85 per sq ft | ₹110 per sq ft |
| System | Elastomeric, "2 coats" | PU, primer + 2 coats + UV top coat |
| Area basis | Flat area 900 sq ft | Flat area + 1 ft parapet upturn = 1,020 sq ft |
| Breaking out old screed | "Extra as per actual" | Included, ₹10,000 |
| Debris removal | Not mentioned | Included |
| GST | "Extra" | 18% shown |
| Warranty | Verbal | 5 years workmanship, written |
At first glance X is cheaper: 900 × 85 = ₹76,500 against 1,020 × 110 = ₹1,12,200 + ₹10,000 = ₹1,22,200. But X has not included the parapet upturn, where many leaks start, nor the breaking out, nor debris. If X adds the upturn (120 sq ft × 85 = ₹10,200) and an extra of, say, ₹15,000 for breaking out and debris, X becomes ₹1,01,700 before GST, and the systems are still not the same. The difference is now about the system and the warranty, which is a fair choice to make.
Put both quotations through the roof and façade cost estimator with the same area to see the range.
Questions to ask at the site visit
- Where do you think the water is coming in, and why?
- What preparation does this surface need, and is it in the rate?
- How will you measure the area for the final bill?
- How many coats, and what coverage or thickness will each coat give?
- Who will do the work: your own team or a subcontractor?
- How will you test the terrace before the top layer?
- What exactly does your warranty cover, and how do I claim?
- What happens if it rains during the work?
Payment terms that protect both sides
A common, reasonable pattern is a modest advance for material, stage payments as layers are completed and inspected, and a retention held until the first monsoon has passed without leaks. The retention and payment calculator works out what is due at each stage. Avoid paying most of the amount before the work is done.
Guides in this section
- Terrace waterproofing estimate: worked example
- Metal roof replacement estimate: worked example
- Apartment façade repainting cost per flat
- Roof and façade contract and warranty checklist
- Repair or replace a roof: how to decide
For how each system is priced, see roof and façade cost per sq ft in India.
FAQ
Should I accept a quotation "as per actual"?
Only for genuinely uncertain items, such as how much hollow plaster will be found, and only with an agreed rate for that item and a cap or a rule that you approve it before the work.
Is it normal to pay an advance?
A modest advance for material is common. A large advance before any work is a risk. Link payments to stages you can inspect.
Why does one contractor want to inspect from inside the flat below?
Because the pattern of damp patches on the ceiling helps locate where water enters. That is a good sign.
Does a quotation need to be on letterhead?
It helps, but what matters is that it is written, dated, signed and specific. A message or email with the details is better than nothing.
Sources and where to check
- CBIC GST portal — GST on works contracts
- GST portal — check a contractor's GSTIN
- National Consumer Helpline — advice before and after a dispute
