Greater London · London and the South East
Electronic Leak Detection in Harrow
Find out what’s going on with the flat roof membrane before you decide what to do next. We carry out electronic leak detection in Harrow, with photographs and a clear written report.
- Failed seams and laps
- Punctures from foot traffic or tools
- Leaks at pipes, outlets or fixings
Local flat roofs in Harrow
In outer London, interwar semis with hipped, tiled roofs sit alongside older slate-roofed terraces. Hips, bay roofs and later loft conversions are typical of those semis, if your home is one of them. Mixed in with those pitched roofs are plenty of flat ones, over rear extensions, dormers, garages and shops. Headstone Manor, about 1.4 miles north, is one of the historic houses in the wider area around Harrow. Period homes nearby can have lead valleys, tall chimneys and a patchwork of past repairs.
If you look after a building such as Whitmore High School, schools and public buildings often have big flat roofs, and their outlets and upstands need regular checks. For an older house near a landmark such as Church of St Peter, the joins between later flat roofs and the old walls are where problems normally start.
Harrow is about 7 miles south of Watford, in Greater London. Roofs in Harrow get the same thorough look as anywhere else in Greater London. We cover towns and villages across Greater London. Our London page covers surveys nearby.
Postcode districts we cover here for electronic leak detection: HA2, HA1, UB5 and HA3. We offer electronic leak detection to properties on High Street, London Road and Perceval Square. With the B457 and B458 close by, Harrow is easy for us to reach. We also cover the places around Harrow: Roxeth (1 mile south), South Harrow (1 mile south), North Harrow (1 mile north-west), Harrow on the Hill (1 mile south-east) and Rayners Lane (1 mile west). Further out, we also cover London (12 miles south-east), City of Westminster (9 miles south-east), Marylebone (10 miles south-east), Kensington (8 miles south-east), St Pancras (11 miles east) and Shoreditch (12 miles east).
Local landmarks in Harrow
We work in homes and buildings around Kingsfield Arms, Grange Primary School and Northwick Park. Harrow’s nearest station is Harrow-on-the-Hill station, roughly 0.7 miles north-east of the centre. A little further out are St. George's Shopping Centre (0.7 miles north-east) and Clementine Churchill Hospital (1 mile south-east). The countryside around Harrow includes Islip Manor Meadows and Northala Fields.
How electronic leak detection works in Harrow
Water can travel under a flat roof membrane before it shows inside. That makes leaks hard to trace by eye. ELD tests the waterproofing directly, to find where it has been breached. We test and report, and the repair is for your roofer. On suitable roofs, it replaces guesswork with a located breach. The results then follow in a written report with photos. We survey flat roof membranes, single-ply roofs and liquid-applied waterproofing, and people most often book us about stains far from any visible defect and leaking laps in the waterproofing.
On a London roof terrace or a flat roof over a back addition, water often runs under the covering before it shows. Upstands against parapets, outlets and the edge where flat meets pitched are common entry points. In a block or conversion in Harrow, the flat roof is frequently a shared part of the building.
It isn’t only a list of defects. It explains what we found, why it matters and what we recommend, so you can decide what to do next.
- Place
- Harrow (HA2, HA1, UB5, HA3)
- Wider area
- Greater London
- Price
- Quoted for your roof
- Report
- A written report with photos, by email
- Appointments
- Monday to Sunday, daytime
- Cover
- Professional indemnity and public liability
- Phone
- 07833 053749
- Last updated
- 27 October 2026
Your questions about electronic leak detection in Harrow
Can parking be tricky for a visit in Harrow?
It rarely stops a survey, but it is worth planning. Tell us what parking is available nearby, and the visit is planned around it.
Is my home in Harrow listed or in a conservation area?
You can check whether a building is listed on Historic England’s list, and your council can tell you if it is 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.
Does ELD work under paving or planting?
In some cases. It depends on the build-up and the layers above the membrane and parts may need to be lifted. We’ll discuss it before we quote.
How many surveys have you done?
More than 5,000 surveys over 20+ years, across London and South East England.
What’s the price of ELD?
Electronic leak detection is quoted for your roof, because the method depends on the roof. The price depends on the roof’s size and build-up. To get a quote, phone 07833 053749 or email us.
Do I need to be at home?
It depends on what we need to see. For inside areas and the loft space, someone has to give us access; we’ll agree the details when you book.
Do you look in the loft space?
If the survey needs it and the loft space can be reached safely, yes. A clear path to the hatch helps, and if the loft can’t be reached safely, the report says so.
What we’re asked to look at in Harrow
A breach can be left during installation. ELD on a new roof can show holes before they cause leaks.
Common reasons to book include:
- New roofs to check before paving or planting
- A flat roof leak that cannot be traced
- Leaks under green or ballasted roofs
- Leaks showing away from the breach
If you run a business near St. George's Shopping Centre, the flat roofs over shops and commercial units are worth checking before a leak, not after.
What to check before booking
- What experience they bring
- Whether the price includes VAT
- What insurance they carry
- Whether you get a written report with photos
Honest limits
Some things can’t be seen without opening up the roof, and that sets some limits:
- Fixing the holes we find
- Build-ups without a suitable layer below
- Moisture spread under the membrane
If in doubt, call 07833 053749 or email us and we’ll point you to the right survey before booking. What our survey covers.
What this survey covers
- Flat roof membranes
- Green roofs
- Liquid-applied waterproofing
- Commercial flat roofs
- Single-ply roofs
- Roof terraces and balconies
Useful tips for Harrow property owners
You do not need to be a roofer to help. What helps most:
- Keep a note of leaks after rain
- Ask contractors to protect the membrane
- Keep outlets clear of debris
- Act on new leaks promptly
The report records each breach location with photos. Pass it to your roofer to repair the breach points.
Ask trades working on the roof to protect the membrane when fitting equipment. Check the roof after they’ve finished.
Also in Harrow
Why act early in Harrow
Not every leak is in the membrane. ELD helps rule the membrane in or out, so other causes can be checked. London’s older roofs often have bitumen felt underlay or none 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.
What a survey costs comes down to the roof itself: its size, its height, how many sections it has and how safely it can be seen. We quote electronic leak detection for each roof, as the method and time depend on the roof.
Why book us in Harrow
- A report with photographs
- Drone flown under a CAA Flyer ID and Operator ID
- An independent look at the roof
- Drones and thermal imaging where applicable
See what a roof survey costs and what we found on two real jobs.
How it works
There isn’t much for you to do on the day. Show us any stains, drips or problem areas you know about, and we’ll get on with the inspection. The survey itself takes more time on a big roof than a small one, and the build-up of the roof makes a difference too. From the street, a London terrace usually shows only its front slope or parapet, so a visit in Harrow moves between viewpoints: the pavement, upstairs windows, the loft and any safe spot at the back. If other people live in the building, tell us who can let us into the shared parts.
- We start with what you know about the roof and the leak.
- We check whether the membrane and build-up suit ELD.
- The test method is chosen to suit the roof.
- We test the roof and locate any breaches.
- You get a report with photos of each breach.
Getting ready for the survey
- Make sure the loft hatch can be reached
- Let us know about parking before the day
- Dig out any old roof reports or invoices
Book a survey
Booking is simple: just ring 07833 053749 or use the contact form and give us some details about the property and we’ll recommend the right survey. The price is agreed up front.
Advice
Surveys for landlords and agents in Harrow
Letting agents can arrange access with tenants. We survey seven days a week, which can make access easier.
If you own several properties, surveys can be booked for more than one address. To arrange surveys for several addresses, ring 07833 053749 or use the contact form with the addresses.