Waterproofing is bought blind: you cannot inspect the work once it is covered, and the test is a monsoon away. So you are not really buying a coating — you are buying a method and the honesty behind it. These eight questions reveal both before any money moves.
The eight questions
1. "What do you think is causing it?"
Ask before they quote. A contractor who names a cause from evidence — and can say why — is diagnosing. One who quotes a rate per square foot without looking at the drains or the junctions is selling coating by the yard (the causes they should be naming).
2. "How will you prepare the surface?"
The answer should be longer than the answer about the product. Cleaning back to sound concrete, cutting cracks open, removing failed coating (mistakes one to three).
3. "What will you do at the parapet junction and the drains?"
The specific question that separates experience from enthusiasm. Coving, collaring, turning the coating up the wall — if these words are absent, so is the durability.
4. "Does the drainage need correcting?"
If water stands anywhere, the honest answer is yes, and it costs money. A bid that ignores ponding is priced to fail (driver two).
5. "Which system, and why that one for this surface?"
Chemistry should follow the slab, not the van's contents (the five questions).
6. "How many coats, and what cure time between them?"
Specific numbers from the product specification. Vagueness here predicts under-thickness.
7. "How will we test it before you leave?"
A ponding test or a scheduled post-rain check. "You'll see in the monsoon" is not a test — it is a hope with your money on it.
8. "Can I see a job you did three years ago?"
Not last month — three years. Anyone can hand over a wet coating that looks perfect.
Bids to refuse
- Quotes given without seeing the roof, or from photographs the contractor never asked for
- "Lifetime guarantee" language on a moving, weathered slab (what permanent honestly means)
- Monsoon-season promises to coat a damp surface (why timing matters)
- Scope in one line: "waterproofing of terrace — lump sum". Insist on preparation, detailing, system and test itemised
Frequently asked questions
Is the cheapest bid ever right?
When it prices the same written scope as the others, yes. When it is cheap because the scope is shorter, it is not cheaper — it is less.
Should I supply material myself?
A reasonable arrangement, and it removes any incentive to thin coats — agree quantities from the specification up front.
We cover your area — what do you do differently?
We diagnose from photographs before quoting and say when a problem is not ours to sell to. Start here.