Guide · July 2026
By the time a ceiling stains, the problem has been developing for a season and the repair is no longer small. The reason nobody looked sooner is access — which is exactly what aerial survey removes.
Roofs fail from the top down, and almost nobody looks at the top until water arrives at the bottom.
By the time a ceiling stains, the problem has usually been developing for a season or more, the repair is no longer a small one, and the material that failed may be a long way from where the water appeared.
The reason nobody looked is straightforward. Getting onto a large industrial roof means access equipment, safety procedures, permits and risk — for an inspection that, done properly, takes hours.
A drone survey covers the entire roof surface in high resolution in a single flight, with nobody leaving the ground.
High-resolution visual imagery of every sheet, seam, flashing, penetration and edge detail, at a resolution that resolves individual fasteners. Thermal imagery revealing moisture and insulation problems invisible in ordinary light. A measured overhead map, so areas can be quantified for quoting and planning. And three-dimensional capture where a complex or multi-level roof warrants it.
Membrane deterioration — cracking, blistering, shrinkage, seam separation and UV degradation on flat and low-slope roofs.
Water ponding, which is one of the clearest indicators of drainage failure or deflection, immediately obvious from above and effectively invisible from below.
Moisture intrusion beneath the surface. This is where thermal earns its place: wet insulation and trapped moisture hold heat differently to the dry material around them, so as a roof cools after sunset those areas release heat more slowly and appear as clearly defined warm zones — mapping the extent of a problem that is entirely hidden visually.
Missing, lifted and displaced sheeting, particularly after wind. Storm and hail damage, including impact marks, dents and cracked translucent panels. Flashing and penetration failures around parapets, pipes, vents and skylights, which is where a large proportion of leaks originate. Blocked gutters, outlets and downpipes. Rooftop plant condition, including corrosion and securing failures on HVAC units, ducting and cable trays.
And skylight condition — degradation, cracking and sealing failure. Fragile rooflights are also one of the most common causes of serious falls, which is itself an argument for not walking the roof.
Nobody goes up. No scaffolding, no cherry picker, no rope access, no permit-to-work, no fall risk. On fragile or asbestos sheeting that is not a convenience but a genuine safety difference.
A large industrial roof is surveyed in a fraction of the time a physical inspection takes, and the building operates normally throughout. Every square metre is captured, including areas a person would not safely reach — rather than the accessible parts plus an assumption about the rest.
The survey is also a dated visual record, which matters for insurance claims, dilapidation disputes, contractor disputes, warranty claims and property transactions.
And it repeats. Fly the same roof next year and the comparison shows exactly what has deteriorated and how fast, which turns roof maintenance from reactive into planned.
For the visual survey, ordinary daylight is fine. For the thermal component, the hours after sunset are substantially better, and the reason is worth knowing.
During the day the roof absorbs solar energy. After sunset it begins releasing it — and areas containing trapped moisture, having greater thermal mass, release theirs more slowly. That difference is precisely what makes wet areas visible.
Fly at midday and the whole roof reads uniformly hot. Fly two hours after sunset on a clear, still evening and moisture-affected areas stand out distinctly. A dry spell beforehand gives cleaner results than flying immediately after rain, when the entire surface is wet.
Highveld hail causes damage to sheeting, translucent panels and rooftop plant that often goes undiscovered until the next heavy rain. Post-event aerial inspection gives both a repair picture and documented evidence for a claim, quickly and across an entire portfolio.
Large industrial and agricultural roofs — warehousing, packhouses, poultry houses and implement sheds — present substantial areas that are rarely inspected because doing so properly is disruptive.
Older industrial and agricultural buildings frequently carry asbestos-cement roofing, which is both fragile and hazardous to disturb. Non-contact inspection is clearly preferable, and in some cases the only sensible option.
And sectional title schemes carry a duty to maintain common property. An annual documented roof survey is straightforward to arrange and defensible to present at a general meeting.
A high-resolution roof orthomosaic — a measurable overhead map of the whole roof. Thermal imagery and a thermal orthomosaic where moisture survey is included. A defect register giving each finding with location, description, imagery and severity. An annotated roof plan with defects plotted and areas quantified. Paired visual and thermal imagery for each anomaly. And a prioritised summary separating what needs attention now from what should be monitored.
The survey identifies where problems are, what they appear to be, and how extensive. Confirming the specific repair and its cost is then a matter for a roofing contractor — who arrives knowing exactly where to go, rather than beginning with a survey of their own.
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