Hertfordshire · London and the South East
Electronic leak detection in Harmer Green, Hertfordshire
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 Harmer Green.
- Water coming in under a flat roof
- Leaks under green or ballasted roofs
- New roofs to check before paving or planting
What we look for on each type of roof
Liquid-applied waterproofing
Pinholes in a coating can let water through. Where the roof suits it, testing can find them.
Green and ballasted roofs
ELD is easier on a new roof before it is covered.
Electronic leak detection in Harmer Green: what you get
ELD is a way of pinpointing breaches in a flat roof’s waterproofing membrane. It uses a small electrical current which can only get through the membrane at a breach. That lets us locate holes that are too small to see, so your roofer can repair them. You get a report with photos of each breach found. If you’ve noticed breaches hidden under paving or planting and leaks through a flat roof with no obvious cause, a survey will tell you what’s going on, whatever the roof.
In a village or hamlet like Harmer Green, flat roofs are typically on extensions, garages, outbuildings or barn conversions. They need the same care as any town roof: the covering, the edges, the upstands and where water drains away. The journey and access are planned beforehand. If there are outbuildings or garages with flat roofs, mention them when booking.
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.
- Where
- Harmer Green (AL6)
- Region
- Hertfordshire
- Cost
- Quoted for your roof
- Your report
- Written, with photos, emailed to you
- Survey days
- Monday to Sunday, daytime
- Insurance
- PI and public liability insurance
- Call
- 07833 053749
- Last updated
- 27 October 2026
Should I look at the roof myself first?
You can learn a lot from the ground. With binoculars, look for slipped or missing slates and tiles, gaps along the ridge and leaning chimneys. Never climb onto the roof to look.
Your own check is a good start, but it isn’t a survey. From the ground, valleys, flashings and the backs of chimneys are often out of sight, and those are details a survey looks at closely.
How it works
We work from the outside in: first the slopes, edges and gutters from every safe viewpoint, then the loft space where it can be reached. In total, it takes as long as needed for the size of the roof and how it’s built, which we set out in the quote. Older rural homes like those around Harmer Green can have a main roof, lower lean-to roofs and outbuildings all joined together. Each part is looked at from wherever it can be seen safely.
- We start with what you know about the roof and the leak.
- We check whether the membrane and build-up suit ELD.
- We choose a low-voltage or high-voltage method to match the roof.
- We test the roof and locate any breaches.
- A report with photos shows where each breach is.
Before we arrive
- If it is not your property yet, arrange access through the agent
- Make a note of anything you’d like us to look at
- Let us know where we can park nearby
Getting a price
To book a survey, call 07833 053749 or use the contact form with the address and what you’d like to know about the roof. You’ll know the price before anything is booked.
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What happens if roof problems are left?
Repeated call-outs for the same leak add up. A report showing the breach points gives your roofer a clear target. Older and listed buildings around Harmer Green may need consent and matching materials for repairs, so leaving a defect until it is urgent leaves less time to plan.
All our prices include VAT. We quote electronic leak detection for each roof, as the method and time depend on the roof. We confirm the price for your roof before booking.
Why book with us
- Customer satisfaction of 98%
- An independent look at the roof
- 5,000+ roofs surveyed
- Weekday and weekend surveys
Read what a roof survey costs or our case studies.
Your questions about electronic leak detection in Harmer Green
Do you cover Harmer Green?
Yes, Harmer Green is within the area we cover. Our area covers London and South East England. Just call 07833 053749 or send us an email and let us know about the property, and we’ll talk through which survey suits.
How do I find out if my home in Harmer Green is listed?
Check Historic England’s online list first, then ask the council about conservation areas and any Article 4 direction. The answer matters most when a change of material is on the cards.
Will you fly a drone over my roof?
Yes, where it’s applicable. Our sub-250g drone is flown by a CAA-registered operator with a Flyer ID and Operator ID, and every flight depends on the airspace and the weather.
How much does electronic leak detection cost?
Each roof is quoted on its size and build-up. Send us details of the roof, and call 07833 053749 or drop us an email for a quote.
What does the report include?
You get our findings in writing, part by part, with photos, finishing with recommendations. The most urgent items are made clear.
How soon will I get the report?
Each package has its own report time. Basic: within 48 hours. Standard: 24 to 48 hours. Premium: the same day. If you have a deadline, like an exchange date, tell us when you book.
Does the weather affect the survey?
Light rain doesn’t normally stop a survey, and it can even help show where water is getting in. Heavy rain or strong wind can ground a drone and make the roof unsafe, so if conditions are not right we’ll arrange another day with you.
Nearby places to Harmer Green
Also in Harmer Green
For landlords and managing agents
Landlords, agents and building managers in Harmer Green and across Hertfordshire can book any of our surveys. For a price for a let property or a block, call 07833 053749 or use the contact form.
An agent can book and manage the survey for a landlord. We agree a time with the tenant beforehand.
Signs you need electronic leak detection in Harmer Green
Seams are a common weak point in flat roof waterproofing. A gap that’s hard to see can let water in for months before it shows.
Signs worth acting on include:
- Leaks through a flat roof with no obvious cause
- Leaking laps in the waterproofing
- Waterproofing to test before it is covered
- Holes left by work on the roof
For an older house near a landmark such as Digswell Village Church, later flat-roofed additions are common on older houses, and their edges and upstands often show the first signs of wear.
Before you book anyone
- Whether VAT is in the quoted price
- How soon the report will arrive
- Whether they hold professional indemnity and public liability insurance
- Whether any drone flown is registered with the CAA
Flat roofs in Harmer Green
Slate and clay tile are the usual coverings on older South East houses, with concrete tiles on many later estates, with flat-roofed extensions, dormers and garages common everywhere. Flat roofs fill the gaps in between, on extensions, garages, dormers and business premises. About 1.5 miles south-west lies Digswell House, a reminder of how long the area around Harmer Green has been built on. If your home is one of the older ones, expect a mix of original materials and later repairs on the roof, and a listed home or one in a conservation area may need consent for changes of material.
For landlords with property near Welwyn North station, flat roofs over rear additions and dormers in rented property are worth checking between tenancies. Anyone responsible for a site like Oaklands Primary School will know that ponding and blocked outlets on a wide flat roof are worth catching before the next wet season.
Harmer Green is about 2 miles north of Welwyn Garden City, in Hertfordshire. Wherever you are in Harmer Green, we can come and survey your property, on a weekday, Saturday or Sunday. We cover towns and villages across Hertfordshire. Our London page covers surveys nearby.
All of AL6 is covered for electronic leak detection. We also cover Burnham Green (1 mile east), Tewin Wood (1 mile east), Oaklands (1 mile north-west), Bull's Green (1 mile north-east) and Digswell (1 mile south-west). Further out, we also cover Watford (15 miles south-west), Hemel Hempstead (13 miles south-west), Stevenage (5 miles north), St Albans (8 miles south-west), Bishop's Stortford (15 miles east) and Harpenden (7 miles west).
What’s near Harmer Green
Locally, jobs take us to homes and businesses close to Danesbury Park, Monk's Walk School and The White Horse Public House. The closest station to Harmer Green is Welwyn North station, about 0.8 miles south-west of the centre. Other landmarks nearby include Hertford Castle (4.9 miles south-east) and Queen Elizabeth II Hospital (3.4 miles south). Green spaces nearby include Tewin Orchard and Hopkyns Wood.