The drone has transformed roof surveying over the past five years. What used to be a cherry-picker day or a scaffolding job is today a 30-minute flight with high-resolution images. This article describes the workflow, the legal obligations under EU drone law and the cost structure for owners and clients.
Where drone surveying outperforms scaffolding
- Speed: a complete roof scan of a single-family house takes 20–40 minutes of flight time.
- Safety: no fall risk for personnel, no intervention into the building structure through scaffolding anchors.
- Resolution: modern sensors (e.g. DJI Mavic 3 Enterprise) deliver 20-megapixel images at around 0.1 mm/pixel at 5 m distance – sufficient to detect cracks in roof tiles.
- Cost: one-third to one-tenth of scaffolding or a cherry-picker for pure inspection work.
- Repeatability: images from exactly the same positions enable condition comparison over years.
Where the drone does not replace: material testing on the component (core, strength), extensive repair access, maintenance interventions.
What the drone typically shows
In my practice (using a DJI Mavic 3 Enterprise with Pix4D modelling), inspection flights reliably produce findings on:
- Tile breaks and displacement after storms or settlement.
- Moss and algae as an indicator of drainage problems on roof surfaces.
- Ridge and hip tile mortar – a common failure point.
- Gutters and downpipes – blockages, loose brackets, corrosion.
- Chimney head – pointing, capping, sooting traces.
- Photovoltaic systems – module hot spots (with a thermal-imaging drone), shading, soiling.
- Flat roof membranes – blistering, folding, emergency overflows.
- Chimney/wall flashings – lead flashings, connector sheets.
Legal framework: EU Regulation (EU) 2019/947
Since 31 December 2020, Regulation (EU) 2019/947 applies uniformly across the EU with three risk classes (Open, Specific, Certified). For building inspection with commercially available drones under 25 kg, the Open Category is almost always relevant, with three sub-categories:
| Sub-category | Drone class | Minimum distance to people | Application for building inspection |
|---|---|---|---|
| A1 | < 250 g (C0/C1) | flight over uninvolved persons permitted (with restrictions) | very small drones, limited sensor capability |
| A2 | < 4 kg (C2) | min. 30 m, low-speed mode 5 m | standard for professional inspection |
| A3 | < 25 kg (C3/C4) | 150 m to residential/industrial areas | large plots, rural |
For most building inspections in Düsseldorf, Cologne and the Ruhr area, A2 is the applicable category. Requirements:
- EU competence certificate A1/A3 (online exam at the German Federal Aviation Office – Luftfahrt-Bundesamt, LBA; free of charge).
- EU remote pilot certificate A2 (online theory + confirmed practical self-training + examination).
- e-ID registration of the drone operator with the LBA.
- Drone liability insurance (mandatory under Section 43 of the German Aviation Act, LuftVG).
- Marking: e-ID visible on the drone.
My drone certificate A1/A3 is in place; A2 flights within private-client and TDD mandates are carried out via specialised partners with C2-certified drones.
Where flights are permitted – NRW geo-zones
Deutsche Flugsicherung (DFS) maintains the German geo-zone map (available in the "DFS DroniQ" app). Relevant in NRW:
- Airport control zones (Düsseldorf, Cologne/Bonn, Münster/Osnabrück): flight only with permission.
- Nature reserves: flight during the breeding and rearing season is often prohibited.
- Residential areas: flying over third parties only with consent; advance information to neighbours is recommended.
- State-specific rules: in NRW, no additional bans in principle.
Before every flight, a pre-flight check is mandatory: weather, wind (< 10 m/s safely flyable with a C2 drone), geo-zones, emergency landing areas, battery status.
Workflow of a drone inspection
In my practice an inspection follows this scheme:
- Engagement clarification (15 min): what is the question? Complete roof, chimney, or PV system?
- Pre-flight check (before travel): geo-zone, weather, control zone permission if needed.
- On-site briefing with the client (10 min): data protection notice for neighbours, emergency scenarios.
- Flight (20–60 min): standardised mission, supplemented by manual detail shots at suspect spots.
- Optional thermography flight (additional 30 min, with a dual-sensor drone).
- Data backup (on-site): SD card secured, image quality pre-checked.
- Evaluation (1–3 days in the office): findings list, selected annotated images, optionally a 3D model from photogrammetry.
- Handover report (PDF, 10–25 pages) plus image archive.
Costs 2026 in NRW
| Service | Range |
|---|---|
| Pure visual inspection of single-family house (images + findings list) | 250 – 450 EUR gross |
| Visual inspection + thermography, single-family house | 450 – 750 EUR gross |
| 3D model from photogrammetry (point cloud + mesh) | additional 200 – 500 EUR |
| Inspection of multi-family house up to 6 units | 450 – 900 EUR gross |
| PV system inspection with thermography | 400 – 800 EUR gross |
| Flight requiring approval in airport zone (Düsseldorf) | + 150 – 300 EUR admin effort |
In my buyer support engagements, a drone check of the roof is included in the premium packages and not charged separately.
Data protection and neighbours
Even for a purely private inspection: photo and video recordings that capture neighbouring plots or persons are GDPR-relevant. In practice:
- Inform neighbours before the flight (often by notice or short email).
- Delete unnecessary recordings immediately.
- Store data encrypted, access only by the pilot/client.
- For commercial processing, add to the processing record if needed.
Insurance
A commercial drone liability insurance is mandatory: typical annual premium of 250–600 EUR for a 4 kg drone. My insurance setup is part of the professional indemnity bundle (see TASKS.md, to be in place before 1 July 2026).
Bottom line
The drone inspection is in 2026 the standard method for visual checks on roofs, facades and PV systems. Within the Open Category framework with an A2 competence certificate it can be carried out with legal certainty – the prerequisites are a clean pre-flight check and a deliberate data protection approach. Economically it costs a fraction of scaffolding or a cherry-picker for pure inspection. In the end, the drone flight is a survey tool – and it is precisely this building survey and groundwork assessment that is essential to estimate costs and risks on the roof sensibly.
Related articles:
Next step: Overview of the diagnostics and technology I use, or request a drone flight within a buyer support engagement.
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Would you like this topic assessed for your property in concrete terms? I offer a free initial consultation — fee ranges, scope and available subsidies discussed openly.