Drone vs manual roof inspection. When to fly, when to walk.

Do — for defects. A good roofer reads flashings, seams, and terminations better than any sensor. But visual inspection cannot see wet insulation under an intact-looking membrane, and 'looks fine' is how saturated roofs pass inspections for years. The moisture question and the defect question are different questions; buy the right instrument for each.

Same physics, different coverage and evidence grade. A technician's handheld IR sees a few square metres at a time from oblique angles, on whatever walking pattern the night allows; a drone captures the entire field at consistent angle and altitude with RTK-positioned radiometric frames. On a small roof the difference may not matter. On 5,000+ m², it always does — and walk-on becomes the verification step, not the search.

Small simple roofs (mobilisation overhead), ballasted and inverted assemblies (signal attenuation — assessed case-by-case), active heavy weather, and any job where the leak is already localised to one detail. We say so on the phone and book the right crew instead — the consult is free and occasionally talks you out of a flight.

It gives you the number that decides: measured wet area as a percentage of the field. A roof with 4% saturation in three mapped zones is a repair-and-monitor story; 40% spread through the insulation is a replacement story. Without the map, that decision runs on age and anecdote — usually toward the expensive answer.

Roofer visual: often bundled with maintenance or quoted modestly. Walk-on IR: mid-hundreds to low thousands by roof size. Drone radiometric survey: typically $750–$3,500 single-site, falling per-building in portfolio programs. The drone number usually undercuts walk-on on large roofs while delivering complete coverage and mapping — and all three are rounding errors against one wrong re-roof decision.

Whichever combination the question requires — that is the advantage of one company holding all three layers. Typical sequence on a serious roof problem: fly the radiometric survey, verify mapped zones with on-roof readings or cores, then hand your roofer (or ours to recommend) a scaled repair scope. One accountable report from first flight to fixed roof.