Find the Leak Before You Pay for the Repair
Most roof leak repairs in Singapore start with a contractor's site visit and a quote. The contractor that inspects the roof is usually the one that sells the repair. Without clear evidence of where the water enters, the safe quote is often to re-waterproof the whole roof. On a 1,000 sqm condominium or factory roof, that is a much bigger bill than fixing a failed lap joint or a blocked outlet.
Roof leaks are also hard to trace by eye. Water that enters at one point can travel along the screed under the membrane and drip through the ceiling several metres away. Patching the area above the stain is why so many roof repairs fail at the next thunderstorm.
A thermal drone survey gives you an independent leak map first. It shows which parts of the roof are wet, how far the water has spread and where it most likely gets in. You can then ask contractors to quote against the same findings, and target the repair at the cause.
How a Thermal Drone Finds Roof Leaks
On a flat concrete roof, water that gets past the waterproofing soaks into the screed and any insulation below it, where it stays for days. Wet screed holds heat far longer than dry screed. After a sunny day, as the roof cools in the evening, the wet areas stay warmer and show up clearly on a radiometric thermal camera. This is the method set out in ASTM C1153, the standard practice for finding wet insulation in roofs with infrared imaging.
The drone flies a planned grid over the whole roof and captures thermal and high-resolution visual images on the same flight. The thermal images show where the roof is wet. The visual images show the defect that is letting water in, such as a split membrane lap, a cracked upstand or a blocked outlet. Both are mapped to a roof grid, so each finding has a fixed location your contractor can find.
Timing matters in Singapore's climate. The best window is the evening after a clear, sunny day, one to three days after heavy rain. We check the forecast for each job and schedule the flight for the conditions that give the strongest thermal contrast.
Roof Types We Survey in Singapore
Thermal imaging works better on some roofs than others. This is how each common Singapore roof type responds.
| Roof type | Common on | How leaks usually start | How well thermal works |
|---|---|---|---|
| Flat reinforced concrete roof with membrane | Condominiums, HDB blocks, offices, shophouses | Failed membrane laps, cracked screed, ponding, upstands and plinths | Very well. Wet screed shows up clearly in the evening. |
| Metal deck roof | Factories, warehouses, JTC buildings | Loose or rusted fasteners, side and end laps, gutters, skylight flashings | Partly. Single-skin sheets hold little water, so the visual survey does most of the work. Insulated sandwich panels show wet insulation. |
| Pitched tiled roof | Landed homes, bungalows, terraces | Cracked or slipped tiles, ridge and hip pointing, valleys, flashings | Partly. Thermal shows damp in the roof void below. High-resolution visual finds the broken tiles. |
| Green roof and rooftop garden | Condominiums, malls, offices | Blocked drainage layers and outlets, root damage to the membrane | Limited. Wet soil masks the membrane, so the survey focuses on outlets, edges and the ceiling below. |
| Skylights and glass roofs | Atriums, malls, landed homes | Perished gaskets, failed sealant, blocked drainage channels | Well for the frames and joints. Glass itself reflects, so it is read visually. |
What the Survey Usually Finds
- Failed membrane laps and joints — torch-on and sheet membranes split at the overlaps as they age in the sun.
- Blocked roof outlets and ponding — leaves and debris block the outlets, water sits on the roof after every storm and finds the weak points.
- Cracked upstands and parapet flashings — water enters at the junction between the roof and the parapet wall, then runs under the membrane.
- Plinths and penetrations — the bases of air-conditioning condensers, water tanks, M&E pipes and cable trays are common entry points.
- Expansion joints — the sealant fails as the roof moves with daily heating and cooling.
- Gutter overflow on metal roofs — undersized or blocked box gutters overflow into the building during heavy rain.
Drone Survey vs Other Leak Detection Methods
The methods work best together. A drone survey covers the whole roof quickly, then the other methods confirm the suspect areas.
| Method | What it tells you | Disruption | Best for |
|---|---|---|---|
| Thermal drone survey | Where the whole roof is wet, and the likely entry points | None. No access equipment, nothing opened up. | Large or hard-to-reach roofs, and finding where to look |
| Flood (ponding) test | Whether one bay leaks, after 24–48 hours of standing water | High. The area is out of use and the outlets are blocked. | Testing a small area or a new membrane |
| Moisture meter and core samples | The moisture level at one point | Low to medium. Core holes need patching. | Confirming a thermal finding |
| Electronic leak detection | Pinpoints holes in the membrane | Medium. Needs a technician to walk the whole roof. | Exposed membranes, and quality checks on new waterproofing |
| Handheld thermal camera | Damp patches on a ceiling or wall from inside | Low | A single unit or room, not the roof surface |
Who Is Responsible for the Roof?
Before you arrange a survey, it helps to know who has to fix the roof.
- Condominiums and strata developments — the roof is common property, so the MCST is responsible. A survey gives the council and managing agent clear evidence to tender the repair.
- HDB blocks — the roof is common property maintained by the Town Council. Top-floor residents with a ceiling leak should report it to their Town Council.
- Factories, warehouses and commercial buildings — the owner, or the tenant if the lease says so. Check the repair clause before you start.
- Landed homes — the homeowner. A survey helps you choose between a targeted repair and full re-roofing or re-waterproofing.
Roof Leak Detection Pricing
Prices are for a combined visual and thermal survey. They include CAAS permits, the flight, thermal analysis and the report.
| Roof area | Typical building | Visual + thermal survey |
|---|---|---|
| Under 500 sqm | Landed home, shophouse | $1,200 — $1,800 |
| 500 — 2,000 sqm | Condominium block, office, small factory | $2,000 — $3,500 |
| Over 2,000 sqm | Warehouse, large factory, mall | $3,500 — $7,000 |
A follow-up survey after the repair, to confirm the wet areas are drying out, is quoted separately. See our pricing guide for other services.
What You Receive
- A leak map — the roof plan with every wet area outlined and numbered.
- Thermal and visual images — each finding shown side by side, with temperature readings.
- Likely entry points, ranked — the defects most likely letting water in, in order of priority.
- Repair recommendations — what to fix, and which areas to confirm with a moisture meter or core sample first.
- A report your contractor can price against — so every quote covers the same scope.
The report is usually delivered within 48 hours of the flight. Where leaks also show on the walls below, we can extend the survey to the facade with water ingress detection.
What Thermal Detection Can and Cannot Do
A thermal camera does not see water. It sees the temperature pattern that wet materials leave, so a thermal finding is a strong lead, not a final answer. We report findings as ranked areas to confirm, and recommend a moisture meter or core sample at the key points before the repair is specified.
Results also depend on the weather. Overcast days with no sun to heat the roof give weak contrast, and a survey during or straight after rain can be confused by surface water. Fresh rooftop gardens, thick gravel ballast and single-skin metal sheets also limit what thermal can show. We tell you at the quote stage if your roof type limits the method.
Why Choose SG Drone Inspections
Independent Findings
We find and report the leak; we don't sell waterproofing. Your contractors quote against the same evidence, and the repair is aimed at the cause.
Whole Roof, One Visit
The drone covers the entire roof, including plant decks, parapets and edges, with no access equipment and no disruption to residents or operations.
CAAS-Permitted Operations
Our flights run under the required CAAS operator and activity permits. We handle the airspace approvals, including near Changi, Paya Lebar and Seletar.
Roof and Facade Together
Many leaks start at the roof but appear on the walls below. We can survey the flat roof and the facade in one visit to follow the water to its source.
Frequently Asked Questions
Get a Roof Leak Survey Quote
Send us the building address, the approximate roof area and where the leaks appear inside. We reply with a scope and quote within 24 hours, with no obligation.