Independent Roof Survey · London and the South East
Electronic leak detection
Electronic leak detection to pinpoint holes in flat roof waterproofing membranes, so the leak can be found without stripping the roof.
- Leaks under a flat roof that can’t be traced
- Pinholes and splits in membranes
- Leaks under green roofs and terraces
What our electronic leak detection involves
On a flat roof, water can travel a long way under the covering before it shows inside, so the stain on the ceiling is rarely under the hole. Electronic leak detection (ELD) tests the waterproofing membrane itself to pinpoint where it has been breached. It suits many waterproofing membranes, including roofs under planting or paving where the membrane can’t be seen. The right method depends on the roof build-up, so we ask about the roof before we quote. This is testing only: the report shows where the membrane has failed, with photographs and marked locations.
We survey roofs across London and the South East, with more than 5,000 surveys completed and over 20 years’ experience. We hold professional indemnity and public liability insurance.
Problems we look for
- Leaks under a flat roof that can’t be traced
- Pinholes and splits in membranes
- Leaks under green roofs and terraces
- Damage after other trades have worked on the roof
- New membranes that need testing
Roofs and parts we survey
- Flat roof membranes
- Single-ply roofs
- Liquid-applied waterproofing
- Green roofs
- Roof terraces and balconies
- Commercial flat roofs
How it works
- You tell us about the roof: its size, the membrane, what is on top of it and where the leak shows.
- We confirm whether electronic leak detection suits the roof build-up and quote for the roof.
- We agree a date; surveys run on weekdays, Saturdays and Sundays.
- We test the membrane and mark any breaches we find.
- Your report shows where the membrane has been breached, with photographs.
Which roofs it suits
Electronic leak detection works on many flat roof waterproofing membranes, including those under green roofs, paving and ballast. Some build-ups need a different method, which is why we ask about the roof before we quote.
New membranes
Testing a new membrane before it is covered with insulation, paving or planting means any damage can be found while it is still easy to reach.
Price
Electronic leak detection is quoted for your roof, because the method depends on the membrane and the roof size. Tell us about the roof and we’ll give you a price.
Why it’s worth doing now
On a flat roof, water can travel a long way under the covering before it shows inside. Stripping areas of roof to find a leak is slow and disruptive, and can miss the real breach. Pinpointing the hole first means the work can be aimed at the right place.
What our survey covers and doesn’t
We inspect what can be seen safely: from the ground, from windows and vantage points, from inside the roof space where there is safe access, from the roof where it is safe, and by drone where applicable. Our survey is not a RICS Level 2 or Level 3 building survey, not a structural engineer’s report and not an asbestos survey, and we can’t see under coverings or inside walls without opening them up. Where a roof may contain asbestos, such as cement sheets or soffits on buildings from before 2000, we flag it so a specialist asbestos surveyor can check before it is disturbed.
What affects the price
- The size and height of the roof
- How many roofs there are, including extensions, dormers and garages
- How complex the roof is: valleys, parapets, chimneys and different levels
- Access to the roof space and the roof
- The package you choose: Basic, Standard or Premium
- Whether drone inspection or thermal imaging is needed
- For commercial roofs and blocks, the size of the roof and the number of buildings
What to check before booking a roof surveyor
- What the report includes, and when you’ll get it
- Whether photographs are included
- How the roof will be inspected: from the ground, the loft, the roof or by drone
- Professional indemnity and public liability insurance
- For drone work, a CAA Flyer ID and Operator ID
- What the survey doesn’t cover
- The price, including VAT
After the survey
Use the marked locations and photographs to brief whoever carries out the work. After any work, a new test can confirm the membrane is sound before insulation, paving or planting goes back on top.
Electronic leak detection: common questions
How much does electronic leak detection cost?
It is quoted for your roof, because the method depends on the membrane and the roof size.
Does it work on every flat roof?
It suits many waterproofing membranes, but the method depends on the roof build-up. Tell us about the roof and we’ll confirm whether it’s suitable.
Can you test a green roof or roof terrace?
Often, yes, without lifting the planting or paving. It depends on the build-up underneath.
How is it different from a flood test?
A flood test holds water on the roof to see whether it leaks. Electronic leak detection aims to pinpoint where the membrane has been breached.
Is this a RICS survey?
No. Our roof survey is a specialist inspection of the roof only. It isn’t a RICS Level 2 or Level 3 home survey of the whole building, and it isn’t a structural engineer’s report. Many buyers book it alongside a RICS survey when the roof needs a closer look.
Are you insured?
Yes. We hold professional indemnity and public liability insurance.
When do you carry out surveys?
Surveys are carried out on weekdays, Saturdays and Sundays. Our phone lines are open Monday to Friday 7:30am–9:30pm, Saturday 7:30am–7pm and Sunday 9am–5pm.
Page updated 27 October 2026
Near you
We survey roofs across London and the South East. Electronic Leak Detection in your area:
- London
- Brighton
- Southampton
- Portsmouth
- Reading
- Oxford
- Milton Keynes
- Crawley
- Guildford
- Maidstone
- Canterbury
- Chelmsford
- Croydon
- St Albans
- Basingstoke
- Slough