Greater London · London and the South East
Cannon Hill Electronic Leak Detection
Not sure what state the flat roof membrane is in? You can book electronic leak detection in Cannon Hill and across Greater London.
- Leaks showing away from the breach
- New roofs to check before paving or planting
- Repairs that haven’t stopped the leak
How electronic leak detection works in Cannon Hill
ELD finds breaches in the membrane, not every cause of water getting in. Leaks from walls, copings, rooflights or pipes need other checks. We will tell you if we think the leak is coming from somewhere else. The test shows breaches in the membrane, not water coming through masonry or around frames. Our report keeps that distinction clear. You will also know what to check next. We survey roof terraces and balconies, single-ply roofs and commercial flat roofs, and people most frequently book us about leaks that return after repairs and damp inside with no sign on the roof.
London has a lot of flat roofs: rear additions, dormers, roof terraces and the roofs of blocks and offices. Coverings range from felt and asphalt to EPDM rubber, GRP fibreglass and single-ply membranes, each with its own weak points. In Cannon Hill, as anywhere in London, the right approach depends on what the roof is made of. Older flat roofs are frequently felt or asphalt, newer ones rubber or GRP.
Pictures do a lot of the work in our reports, so you can see each defect rather than just read about it. Anything out of sight on the day is listed as such.
- Place
- Cannon Hill (SW20, SM4, KT3)
- Region
- Greater London
- Price
- Quoted for your roof
- Your report
- A written report with photos, by email
- Appointments
- Monday to Sunday, daytime
- Insured
- Professional indemnity and public liability
- Telephone
- 07833 053749
- Page updated
- 27 October 2026
Electronic leak detection in Cannon Hill: local notes
Further from the centre, London’s housing takes in interwar semis with hipped roofs in clay or concrete tiles as well as slate-roofed terraces. Hips, bay roofs and later loft conversions are typical of those semis, if your home is one of them. Flat roofs on extensions, dormers, garages and business units are found alongside them almost everywhere. Southside House, about 1.2 miles north-west, is one of the historic houses in the wider area around Cannon Hill. Older roofs in the wider area can hide decades of patch repairs, so the detail matters, and any change of roofing material on a listed home needs checking with the council first.
For landlords with property near South Merton station, the flat roof over a let home is worth a look before it becomes a tenant complaint. Take a building like Hillcross Primary School: schools and public buildings frequently have big flat roofs, and their outlets and upstands need regular checks.
Cannon Hill is about 1 mile north-west of Morden, in Greater London. Cannon Hill gets the same service as everywhere else we work: a proper look at everything that’s safely in view, photos and a clear written report. We cover towns and villages across Greater London, from the larger towns to small villages. We also survey roofs in London.
Surveys in SW20, SM4 and KT3 work the same way as everywhere else we cover. You’ll find streets such as Aylward Road, Camborne Road and Botsford Road, all of which we cover. We also cover Bushey Mead (1 mile north-west), Raynes Park (1 mile west), Wimbledon Chase (1 mile north), West Barnes (1 mile west) and Merton Park (1 mile north-east). We also work in nearby towns such as London (9 miles north-east), City of Westminster (8 miles north), Marylebone (9 miles north), Kensington (7 miles north), St Pancras (10 miles north-east) and Shoreditch (11 miles north-east).
What’s near Cannon Hill
Locally, jobs take us to homes and businesses close to The Edward Rayne pub, Cannon Hill Common and Harris Academy Wimbledon and the streets around them. For rail, the closest station is South Merton station, roughly 0.5 miles north-east of the centre. A little further out are St. Anthony's Hospital (1.5 miles south) and Wimbledon Museum (1.6 miles north). Not far away are Cherry Wood and Henman Hill.
What this survey cannot tell you
Every survey has limits, and it is better to know them up front. Bear these in mind:
- Areas we can’t reach or that can’t be tested
- Fixing the holes we find
- How wet the insulation is
If in doubt, phone 07833 053749 or send us an email and we will suggest the right survey. What a survey covers and does not.
Roofs we survey in Cannon Hill
- Flat roof membranes
- Roof terraces and balconies
- Commercial flat roofs
- Green roofs
- Liquid-applied waterproofing
- Single-ply roofs
What you can safely check yourself
A DIY look is useful, but it isn’t a survey. You won’t see flashings, valleys or the backs of chimneys properly from ground level.
If you have a loft with safe access, take a look inside. Take a torch and only step on boards or joists, checking for stains, damp wood or chinks of daylight.
What we do, step by step
We photograph the roof as we go, so the report shows exactly what we saw. Close-ups come from the safest viewpoint available, including by drone where it’s applicable and the weather allows. A typical visit takes more time on a big roof than a small one, and the build-up of the roof makes a difference too. In Cannon Hill, as in much of London, plenty of properties are flats or terraces without side access, so rear slopes are viewed from windows, the loft or, where a flight is allowed, by drone. If the building has a managing agent or access rules, tell us when you book.
- We ask about the roof, its age, its membrane and where leaks appear inside.
- We check that the membrane and build-up suit electronic leak detection.
- The testing method is chosen to suit the membrane and build-up.
- The roof is tested and any breaches are located.
- The breaches are recorded with photos in a report for your roofer.
Before the survey
- Move anything stored under the loft hatch
- Let us know about parking before the day
- Agree roof access with the managing agent if it’s shared
Arrange a survey
We confirm the price for your survey before booking, so you know where you stand. Electronic leak detection is quoted for your roof, because the method depends on the roof. For a price for your roof, call 07833 053749 or send us an email.
Related advice
Also near Cannon Hill
Also in Cannon Hill
Different roofs, different checks
Green and ballasted roofs
Some layers may need lifting for testing. We explain what’s needed when we quote.
Single-ply membranes
Single-ply can be punctured by tools or fixings. Testing helps find them.
Do you need electronic leak detection in Cannon Hill?
Water travels under flat roof membranes. The stain inside can be far from the hole, so tracing it by eye is difficult.
Most people get in touch when they’ve noticed one of these:
- Leaks showing away from the breach
- Breaches hidden under paving or planting
- Water coming in under a flat roof
- New roofs to check before paving or planting
For businesses in and around places such as Bentall Centre, outlets and upstands on commercial flat roofs are the places to check before trouble starts.
Before booking anyone
- Their drone registration, if they fly one
- What’s outside the scope of the survey
- Whether the loft is part of the inspection
- What exactly goes into their report
What happens if roof problems are left?
Not every leak is in the membrane. Testing shows whether the membrane is breached, so other causes can be checked. Many older London roofs have only old felt under the slates, or no underlay at all, so a slipped slate can soon mean water inside. Left alone, that means wet timbers and plaster, which is a far bigger job than the roof fault itself.
Bigger, taller and commercial roofs take more time to survey, so they’re priced to match. The price is confirmed before booking.
Why choose Independent Roof Survey in Cannon Hill
- Visits on any day of the week
- A report with photos
- Two decades and more of roof surveys
- CAA-registered drone operator (Flyer ID and Operator ID)
See what a roof survey costs and our case studies.
Cannon Hill: your questions answered
Is Cannon Hill in the area you cover?
Yes, Cannon Hill is within the area we cover. We cover the whole of London and South East England. You can ring 07833 053749 or use the contact form with the address and some details.
Does a conservation area affect roof work in Cannon Hill?
You can check whether a building is listed on Historic England’s list, and your council can tell you if it’s in a conservation area. Listed building consent is needed for changes that affect a listed building’s special interest, and conservation areas can limit changes of roofing material.
What happens next?
You will receive the report by email, and what you do next is up to you: raise it with a seller, send it to an insurer, brief a roofer or share it with a managing agent.
Is my roof suitable for ELD?
It depends on the membrane and the build-up. Share any details you have and we will confirm suitability.
Will you repair the leak?
No. We test the membrane and report. The report shows where each breach is for your roofer to repair.
How quickly is the report sent?
It depends on the package: the Basic Survey report arrives within 48 hours, the Standard Survey in 24 to 48 hours and the Premium Survey the same day. The report is emailed to you.
What will the report tell me?
It works through the roof part by part, in writing and with photos, finishing with recommendations. Points are put by urgency where it matters.