What a flight settles and what it does not
A drone roof inspection answers questions about the visible surface faster and more safely than anything else, and it answers nothing about what is underneath. That line is worth holding on to, because it is where most disappointment with aerial work comes from.
A flight establishes coverage. It shows the condition of the field, the state of the upper details, where debris and water are sitting, what equipment is up there and how the whole thing hangs together. It documents a roof after a storm before anyone has been on it, which is often the most useful set of images anyone takes that season.
It does not establish the things that decide repair against replacement. It cannot feel a membrane go soft underfoot. It cannot lift a lap to see whether the weld is real or whether somebody ran sealant along the edge of a failure. It cannot probe a pitch pan, count the layers in the build up, or tell you that the insulation under a sound looking surface is wet. Those answers come from a walk, from an opening in the roof, or from a moisture survey.
Where flying earns its place
On a roof that cannot be walked safely, the choice is not between a flight and a walk. It is between a flight and nothing. Fragile sheeting, steep slopes, a deck of uncertain strength and a building with no safe access are all cases where an aerial pass tells you something you were otherwise going to guess at.
It also earns its place on scale. A very large roof takes a long time to cover on foot, and flying it first shows where the problems concentrate, so the walk that follows goes to the right places instead of everywhere. On tall buildings, it is often the only way to look at the outer face of a parapet or the joints in a coping.
What you receive
An image set with the date on it, a plan view with the findings marked, and a written account of what the flight showed. The report separates what the images establish from what they merely suggest, and it lists plainly what could not be settled from the air.
That last list is the part to read first. If it contains the question you bought the inspection to answer, the honest next step is a walk or a test, and we would rather say so than let an image set do work it cannot do.
Common questions
What can a drone show that someone standing on the roof cannot?
Three things, mainly: the whole roof in one frame, the surfaces that face outwards, and anything that should not be walked on.
- From the deck you see one section, and patterns only become obvious from above
- Ponding rings following a sagging line across several bays, or damage clustered by wind
- The outer face of a parapet, coping joints and the wall above a roof junction
- Those are frequent sources of water that gets blamed on the membrane
- Steep metal, fragile sheeting and storm debris can be photographed without the risk
None of that replaces being up there. It adds a view that being up there does not give you, which is why a flight belongs alongside a walk rather than instead of one.
What stops a flight going ahead on the day?
Weather is the usual one. Wind at roof height is stronger than at ground level, and above a point the images stop being steady enough to be worth anything.
- Rain stops a flight outright
- Flat light hides surface texture and shallow ponding that raking light reveals
- A technically fine flight can then produce images that tell you less
- Airspace, the surrounding property and site rules decide whether a location can be flown
- Trees, overhead lines, tall neighbors and busy ground below narrow what is possible
We check this before the booking rather than after, because a flight that cannot legally or safely happen is not a scheduling problem, it is a different inspection. Where a site cannot be flown we say what the alternative is.
Can the drone tell you if the insulation is wet?
Not with an ordinary camera. A camera records the top surface, and wet insulation sits under the membrane where no visible light reaches it.
- A roof can photograph perfectly and be soaked underneath
- That is why we do not describe a flight as a condition survey
- A drone can carry a thermal camera, which covers a large roof quickly
- The scan needs the right window after dark and a dry surface
- Resolution from height is coarser than a camera carried on the roof
Thermal imaging produces suspicions rather than conclusions, and whatever it shows still has to be checked with a probe, a meter or a core before anyone spends money. If your question is moisture in the assembly, a moisture survey is the job and a flight is half of it.
Where do you fly from, and do you need to come inside?
Usually from ground level on the property, clear of people, parking and cables, with a spot that keeps the aircraft in view throughout the flight.
- On a tight urban site that spot is the hard part of the whole job
- Worth a conversation before the date is set
- Launching from an adjacent roof or yard needs somebody's permission in advance
- We do not normally need to go inside for the flight itself
- That is one reason flying suits occupied property and tenanted units
Two exceptions. Where the interior shows signs of a leak, the underside of the deck is often the fastest route to a direction to search. And where the flight is combined with a walk, the normal access arrangements apply: hatch keys, escorts, permits and tenant notice.
Do I get the photographs and the video?
Yes. The image set is part of what you are paying for, and it is handed over with the report rather than kept as leverage for the repair work.
- You get the plan view, the coverage passes and the close images behind each finding
- Every image carries the date
- Keep the file, because next year's comparison is then against something specific
- A dated set taken before a storm is far more useful than anything after one
- An aerial photograph shows the top of a roof on one day, in one light
It does not show what is under the membrane or what a lap does when it is lifted. A finding marked on an image is a finding to be checked, not a repair to be ordered blind.