RAAC surveys, assisted by drones
Roof imagery, 3D models and thermal flat roof investigation to support RAAC assessments, all without scaffolding.
Available Files: 4K Imagery, 3D Models & Thermal Reports
4K
Roof Imagery
3D
Deflection Models
Level 2
Thermographer
0
Days of Scaffold
RAAC Inspections Assisted by Drones
Reinforced autoclaved aerated concrete (RAAC) is a lightweight concrete, made without coarse aggregate and cured under heat and pressure. It was used for roof planks, floors and wall panels, mainly in public sector and commercial buildings, between the 1950s and 1990s.
RAAC is much weaker than conventional reinforced concrete, and it’s especially vulnerable to water ingress, which can corrode the reinforcement and contribute to failure.
Drones can’t identify RAAC on their own, as it’s usually hidden, but they give the structural engineers and surveyors assessing it a fast, scaffold-free view of the roof, with imaging and 3D models to check for deflection and thermal imaging to find water ingress.
Example Image Quality
Click each image to view example image quality
What Your RAAC Roof Survey Includes
Every survey is delivered through our online portal, ready to share with your structural engineer or surveyor.
| Deliverable | What it is | Included |
|---|---|---|
| UHD 4K roof imagery | Detailed images of the whole roof covering, recording every visible anomaly. | Standard |
| Organised by building | Images sorted by building and roof area, so issues are easy to locate. | Standard |
| Consistent reporting | The same capture and reporting at every site, across the UK. | Standard |
| Secure online portal | All images, models and reports in one place, with no large downloads. | Standard |
| 3D model and point cloud | Photogrammetry models to help identify roof deflection and sagging. | Optional |
| Thermal flat roof survey | After-dark thermal imaging to find water ingress under the roof covering. | Optional |
| Thermographer’s report | Findings from our BINDT Level 2 qualified thermographer. | Optional |
Our surveys support, but don’t replace, a structural engineer’s RAAC investigation and assessment.
At a Glance
Capture
UHD 4K + 3D
Access required
Usually none
Imagery issued
Within 48 hours
Thermal survey
Optional
Scaffold needed
None
Coverage
Mainland UK
Get a Quote
Send us an address. We will come back the same working day with a price and a scope.
What a Drone Survey Can Show
Drones can’t see RAAC through a roof covering, but they can record the warning signs engineers look for, including:
Water under the roof covering can speed up corrosion of the reinforcement, reduce insulation performance and ultimately contribute to failure of the planks. Finding it early gives your engineers the information they need to act.
The result?
A fast, scaffold-free view of the roof, giving engineers the evidence they need to prioritise investigation and remediation.
__ Thermal investigation
Find water ingress in RAAC roofs
Carried out in the right conditions, a thermal flat roof survey shows where moisture is trapped under the roof covering. For RAAC roofs that matters, because water can speed up corrosion of the reinforcement and weaken the planks.
Our BINDT Level 2 qualified thermographers capture, tune and analyse the thermal images, and write reports your engineers can rely on. Find out more about thermal flat roof surveys.
Moisture mapped across the roof, without opening it up.
CAA
CAA Operational Authorisation 11363
Fully insured, with £10m public liability and specialist UAV cover
Why drones
Why use drones for RAAC roofs?
Getting people onto a roof that may contain RAAC carries risk. Drones capture the roof in detail without anyone stepping on it.
- No one on the roof. Nobody needs to walk on planks that may be weakened.
- Scaffold-free. No access equipment needed to record the roof.
- 3D deflection data. Models help engineers spot sagging.
- Thermal where needed. Find water ingress under the covering.
- Consistent nationwide. The same reporting at every site in a programme.
The whole roof recorded without anyone stepping on it.
Sectors We Cover
RAAC surveys for schools, councils & estates
RAAC has been found in schools, hospitals, council buildings and other public and commercial properties. We support structural engineers, surveyors and estates teams across the UK.
Our service is suitable for
- ›Offices and commercial premises
- ›Warehouses, factories and industrial buildings
- ›Retail units, shopping centres and retail parks
- ›Residential apartment blocks and housing developments
- ›Housing association and social housing properties
- ›Schools, colleges, universities and education estates
- ›Hospitals, clinics and other healthcare buildings
- ›Local authority and public-sector buildings
- ›Historic, heritage and listed buildings
- ›Hotels, leisure centres and hospitality properties
- ›Care homes and assisted-living facilities
- ›Distribution centres and logistics hubs
- ›Churches and places of worship
- ›Agricultural and rural buildings
- ›MOD, defence and secure estate buildings
- ›Prisons and custodial facilities
- ›Construction sites and newly completed developments
- ›Multi-site commercial and residential property portfolios
For clients with assets spread over large areas, we build a consistent visual library of the external envelope of every asset, helping teams compare condition and prioritise maintenance.
Why choose us
Why choose Drone Site Surveys?
Drone Site Surveys specialises in professional survey and inspection data capture, providing detailed imagery to support the investigation of Reinforced Autoclaved Aerated Concrete (RAAC) in buildings.
Our experienced pilots work across commercial properties, schools, hospitals and public sector buildings, capturing high-resolution imagery of roofs, structural elements and other difficult-to-access areas. We understand the importance of consistent, detailed visual evidence to help structural engineers and building surveyors identify potential RAAC, assess visible deterioration and make informed decisions about further investigation and remedial works.
Clients choose Drone Site Surveys for our specialist experience, professional standards and independent approach:
How it works
Our RAAC roof survey process
From first enquiry to secure delivery, every survey follows the same six steps, so you always know what happens next and when.
Tell us about the property
Email us the building addresses and what you need, whether that’s roof imagery, 3D models, thermal surveys or all three. We’ll come back with the options available.
Planning and quote
We carry out a desktop assessment of the property and the surrounding airspace, check the survey against current UK drone regulations, and prepare your quote. You receive it by email with no obligation, along with the airspace map for your site and an example delivery so you can see exactly what you’ll be getting.
Booking your date
Once you’re happy with the quote we add your job to the schedule and start monitoring the Met Office forecast. In the meantime we prepare the pre-flight paperwork, including our risk assessment and method statement (RAMS), which we can send over for your records. As soon as we have a clear weather window and pilot availability, we confirm your attendance date. You don’t normally need to be on site.
The survey
Our CAA approved pilot captures the roof in UHD 4K, with photogrammetry for 3D models and after-dark thermal capture where specified.
Processing
Every image is checked and organised into colour-coded folders. Any thermal analysis or reporting you’ve asked for is completed at this stage.
Delivery
We email you a link to our secure online portal, where your imagery, reports and any other agreed outputs are ready to view, download and share with your team or contractors. Alongside the deliverables you’ll find a folder containing the pre-flight paperwork, a copy of the drone airspace map for your site and any other relevant documents, so everything from the survey is in one place.
Request a Quote
Request a RAAC roof survey quote
Whether you’re investigating one building or running a programme across an estate, we can tailor the survey to your buildings and your requirements.
Send us the address and a brief description of what you need, and we will come back with clear pricing and deliverable options.
Prefer to Speak to Us?
If you’d rather speak to one of the team, that’s no problem. Simply call the number below and one of our team will be more than happy to help.
Get a Quote
In The Know
Frequently Asked
Questions
Answers to the questions we are asked most often about RAAC roof surveys. If yours is not covered here, give us a call.
What is RAAC?
Reinforced autoclaved aerated concrete: a lightweight concrete used for roof planks, floors and wall panels, mainly in public sector and commercial buildings between the 1950s and 1990s. It’s much weaker than conventional reinforced concrete.
Can a drone identify RAAC?
No. RAAC is usually hidden beneath roof coverings and finishes, so it needs to be identified by a structural engineer or surveyor. Drones support that work by recording the roof and signs of deterioration.
How can drones help with RAAC?
Drones capture detailed roof imagery, 3D models that help identify deflection and sagging, and thermal images that show water ingress, all without scaffolding or anyone on the roof.
Why does water ingress matter?
Water getting into a RAAC roof can speed up corrosion of the reinforcement and weaken the planks. Finding it early helps engineers prioritise remediation.
Where can I find official guidance?
The government and the Institution of Structural Engineers publish guidance on identifying and managing RAAC. We recommend following the latest guidance and appointing a structural engineer.
Can you survey a whole estate?
Yes. We’re set up to deliver multi-site programmes across the UK, with consistent imagery and reporting at every site.
Do you need access to the building?
Usually we just need a safe take-off area nearby. Nobody needs to go on the roof.