Hertfordshire · London and the South East
Old Knebworth Electronic Leak Detection
Electronic leak detection to pinpoint holes in flat roof membranes for Old Knebworth and the rest of Hertfordshire. Surveys run on weekdays, Saturdays and Sundays.
- Damp inside with no sign on the roof
- Breaches around outlets and penetrations
- Waterproofing to test before it is covered
Electronic leak detection in Old Knebworth
ELD can be carried out in more than one way. Low-voltage testing is usually done with the surface wet and high-voltage methods need the membrane dry and exposed. Which one suits depends on the membrane and the layers of the roof and we explain which we will use. If neither method suits your roof, we will tell you at the outset. If you’ve noticed damage from equipment installers and waterproofing to test before it’s covered, a survey will tell you what’s going on, whatever the roof.
Older buildings in small places like Old Knebworth may be listed or in a conservation area, which can shape what a new flat roof may look like. Check with the council before planning any change of material. Knowing the roof’s condition is the starting point. Changes that affect a listed building’s special interest need listed building consent.
It is not 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.
- Location
- Old Knebworth (SG3)
- Wider area
- Hertfordshire
- Cost
- Quoted for your roof
- Your report
- Emailed report with photos and recommendations
- Appointments
- Monday to Sunday, daytime
- Cover
- Professional indemnity and public liability
- Phone
- 07833 053749
- Page updated
- 27 October 2026
Honest limits
This isn’t a RICS building survey, a structural engineer’s report or an asbestos survey. It also has these limits:
- Areas we can’t reach or that cannot be tested
- Moisture spread under the membrane
- Carrying out the repair work
If you are not sure which survey you need, ring 07833 053749 or send us an email and we’ll give you a straight answer before booking. The full list of what we check.
Roof types and parts we check
- Green roofs
- Roof terraces and balconies
- Flat roof membranes
- Liquid-applied waterproofing
- Single-ply roofs
- Commercial flat roofs
How the survey works
Time on site depends on the size and shape of the roof, but as a rough guide the survey takes longer on a large roof than a small one, with the construction of the roof playing a part too. You are welcome to ask questions while we’re there. Older rural homes like those around Old Knebworth can have a main roof, lower lean-to roofs and outbuildings all joined together. We work round each section in turn, from the safest viewpoints, and anything we cannot see is noted.
- First, we confirm which roof areas are included.
- The surface is prepared for the chosen method.
- Testing runs across the agreed area.
- Each breach found is located and recorded.
- You receive the results to pass to your roofer.
Before we arrive
- Buyers: confirm access with the estate agent or seller
- Make a note of anything you’d like us to look at
- For a flat or shared roof, check access with the freeholder or managing agent
Getting a price
To book a survey, ring 07833 053749 or drop us an email with the address and what you’d like to know about the roof. We will confirm the price before you book.
Read more
Checking the roof from ground level
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.
After heavy rain, check ceilings and the tops of walls for new stains. Photograph them and note the date.
Electronic leak detection in Old Knebworth: local notes
Historic houses like Knebworth House, about 0.2 miles north-west, show how far back building in the area around Old Knebworth goes. On older houses around here, roofs often carry the marks of earlier repairs, from replaced slates to new lead, and the council can say whether a home is in a conservation area. Across the South East, older homes tend to have slate or clay tiles, and many later ones concrete tiles, and flat-roofed additions turn up almost everywhere. Mixed in with those pitched roofs are lots of flat ones, over rear extensions, dormers, garages and shops.
For landlords with property near Knebworth station, flat roofs on let property tend to be checked only when they fail, which is the costly way round. If you own one of the older houses in the streets near Church of St Mary and St Thomas, later flat-roofed additions are common on older houses, and their edges and upstands frequently show the first signs of wear.
Old Knebworth is about 3 miles south-west of Stevenage, in Hertfordshire. We survey roofs in Old Knebworth and the surrounding area across London and South East England. Old Knebworth is one of the towns and villages in Hertfordshire we cover. Our London page covers surveys nearby.
Every address in SG3 is within our area for electronic leak detection. Local streets include Old Knebworth Lane and Park Lane, and we cover them all. If you’re just outside Old Knebworth, we cover Nup End Green (1 mile south-west), Driver's End (1 mile south-west), Rableyheath (1 mile south), Pottersheath (1 mile south) and Langley (2 miles north-west). Within a short drive, we also cover Hemel Hempstead (13 miles south-west), Stevenage (3 miles north-east), St Albans (10 miles south-west), Welwyn Garden City (5 miles south), Harpenden (7 miles south-west) and Hitchin (6 miles north-west).
Landmarks near Old Knebworth
Locally, jobs take us to homes and businesses close to Knebworth Park and Robin Hood And Little John Public House. Old Knebworth’s nearest station is Knebworth station, about 1 mile east of the centre. A little further out are Lister Hospital (3.7 miles north) and Stevenage Museum (2.2 miles north). For a walk, there’s Mardley Heath.
Towns and villages near Old Knebworth
Also in Old Knebworth
Before and after the survey
Here are a few things we’d tell any owner, before and after a survey:
- Stay off the flat roof unless needed
- Make sure trades protect the waterproofing
- Get leaks traced quickly
- Don’t keep patching the same spot
File the report with your roof paperwork. It shows the condition of the membrane on that date.
Consider testing a new membrane before it’s covered. It’s easier to find holes before more layers are added.
Your questions about electronic leak detection in Old Knebworth
Is my home in Old Knebworth listed or in a conservation area?
Historic England’s list shows listed buildings, and the local council can tell you about conservation areas. If a home is listed, changes that affect its special interest need listed building consent, and in a conservation area re-roofing in different materials may need permission.
Do you cover smaller places like Old Knebworth?
Yes, Old Knebworth is on our map. Villages and rural addresses get the same survey as a town house, with the route planned beforehand.
Does the weather affect the survey?
Light rain does not normally stop a survey. Heavy rain or strong wind can ground a drone and make the roof unsafe, so we’ll agree a new date if the weather isn’t suitable.
Can you survey at the weekend?
We carry out surveys seven days a week. To find a day that suits you, call 07833 053749 or use the contact form.
Do you carry professional indemnity insurance?
Our surveys are covered by professional indemnity and public liability insurance. Ask if you need details for a managing agent or building owner.
What do I do with the report?
We email you the written report with photographs and recommendations. You can use it to talk to a seller, an insurer, a roofer or a managing agent, whichever applies.
Can you survey a shared roof?
Yes. A shared roof needs access agreed first. Tell us about it when booking and we’ll explain what’s needed.
Different roofs, different checks
EPDM rubber roofs
EPDM is a long-lasting flat roof membrane, but punctures and seam failures still happen.
Green and ballasted roofs
ELD is easier on a new roof before it’s covered.
When to book a survey in Old Knebworth
Seams are a common weak point in flat roof waterproofing. A gap that is hard to see can let water in long before anyone notices.
Common reasons to book include:
- Water coming in under a flat roof
- Holes left by work on the roof
- Patched roofs that still leak
- Leaks showing away from the breach
If you look after a building like Barnwell School, ponding and blocked outlets on a wide flat roof are worth catching before the next wet season.
Before you book any roof surveyor
- How long the report takes to arrive
- What happens after the report arrives
- Which limits apply to the survey
- What insurance they carry