Hertfordshire · London and the South East
Roof Leak Investigation in Knebworth
We carry out roof leak investigations in Knebworth and the rest of Hertfordshire. We survey on any day of the week.
- Wet patches high on an inside wall
- Water coming in around a roof light or dormer
- Damp ceilings under a flat roof
Roof leak investigation in Knebworth
Flat roofs leak in their own ways. Common causes are splits and blisters, tired upstands and outlets that do not drain. Standing water puts extra pressure on every weak point. We check the roof surface and the ceiling below. Flat roofs over extensions, garages and dormers are frequent sources of leaks. Felt often lasts around 15 to 20 years, so age is part of the picture. Typical surveys look at water that shows only in certain storms and water marks that spread in wet weather, on flat roof details, rooflights and dormers and chimney stacks.
Chimney stacks on older houses around places like Knebworth can let water in, at the flashings, the pointing or the mortar round the pots. Damp on a chimney breast is not always rain from above, which is why it is worth tracing properly. It’s worth looking at the stack from outside and at the timbers beside it in the loft.
Most points in the report come with a picture, so you can see each defect rather than just read about it. If something couldn’t be seen safely, the report is clear about it.
- Where
- Knebworth (SG3)
- Region
- Hertfordshire
- Prices
- From £150 inc. VAT
- Reports
- Written, with photos, emailed to you
- Appointments
- Monday to Sunday, daytime
- Insured
- Professional indemnity and public liability
- Telephone
- 07833 053749
- Page updated
- 27 October 2026
The survey, step by step
The visit usually starts outside and finishes in the loft: outside views come first, then the loft space if there is safe access. All told, expect about one to two hours on an ordinary house, though large, tall or awkward roofs take more time. Parking around Knebworth is typically easier than in a town centre, but mention lanes, gates or long drives. On bungalows and lower roofs, much can be seen from the ground, with the loft showing the underside, while taller roofs may need other vantage points or the drone where applicable.
- We start with your notes and photos of the leak.
- Inside, we check the stain and the ceiling around it.
- From the roof space, we trace the water’s route where there’s safe access.
- Outside, we check flashings, valleys, chimneys, gutters and flat roof details from each safe vantage point.
- We email a written report showing where the water most likely gets in.
Getting ready for the survey
- Clear the way to the loft hatch
- Agree roof access with the managing agent if it is shared
- Keep pets inside or away from the areas we are looking at
How to book
Unsure which package suits your roof? It’s easiest to call 07833 053749 or use the contact form and describe the roof and what’s worrying you. We’ll talk you through the options and what they cost.
Advice
For landlords and managing agents
A roof problem in a let property affects your tenants as well as the building. A survey helps you spot issues early and plan the work around your tenants.
If the property is let, the agent or a tenant can let us in. Surveys run on weekdays, Saturdays and Sundays, which helps when tenants work during the week.
Places near Knebworth
What else we do in Knebworth
Roof by roof
Flat roof upstands and outlets
Each flat roof relies on its outlets to drain. A blocked outlet leaves water standing, which tests every joint. Outlets and the area around them are checked.
Slate and tile slopes
Ridge and hip tiles can loosen as their mortar cracks. Water then gets in along the top of the roof.
Should I look at the roof myself first?
Watch the gutters in a downpour, from a window or the ground. Water spilling over the edge can be a sign of a blockage or a gutter that has dropped.
You can learn a lot from ground level. Binoculars help you spot slipped slates or tiles, gaps along the ridge and a leaning stack. Please don’t climb up for a closer look.
Knebworth roofs and the weather
Older houses in the South East often have slate or clay tile roofs, while many later estates have concrete tiles. Where water gets in depends a good deal on what the roof is made of and how it’s detailed. Historic houses such as Knebworth House, about 1.3 miles north-west, show how far back building in the area around Knebworth goes. If you own one of the older houses, expect a mix of original materials and later repairs on the roof, and any change of roofing material on a listed home needs checking with the council first.
If you live in an older home near Church of St Martin, water on an older roof tends to find its way in at the lead, the valleys or the chimney. For landlords with property near Knebworth station, a clear finding on where water gets in helps you brief a roofer right away.
Knebworth is about 3 miles south of Stevenage, in Hertfordshire. Anywhere in Knebworth, we can come and survey your property, on a weekday, Saturday or Sunday. Our area takes in places right across Hertfordshire, from the larger towns to small villages. There’s also a page for London.
Every address in SG3 is covered for roof leak investigations, from the main roads to the quietest streets. Streets in the area include London Road, Deanscroft and Lytton Fields. We also cover Woolmer Green (1 mile south), Bragbury End (1 mile north-east), Oaklands (2 miles south), Datchworth (2 miles south-east) and Shephall (2 miles north). We also work in nearby towns such as Hemel Hempstead (14 miles south-west), Stevenage (3 miles north), St Albans (10 miles south-west), Bishop's Stortford (15 miles east), Welwyn Garden City (5 miles south) and Harpenden (8 miles south-west).
Near you in Knebworth
Locally, jobs take us to homes and businesses close to Barnwell School and Knebworth Park, among other places. There’s a railway station in Knebworth itself: Knebworth station. A little further out are Benington Castle (3.6 miles north-east) and Datchworth Museum (1.7 miles south-east). The countryside around Knebworth includes Mardley Heath.
What we’re asked to look at in Knebworth
Chimneys can let water in by several routes. Water can enter through crumbling mortar, cracked flaunching, worn flashings or uncapped pots. It can show up on the chimney breast, nearby ceilings or in the roof space.
People usually book a survey after spotting something like this:
- Wet patches high on an inside wall
- Stains around a skylight
- Water through the ceiling under a flat roof
- Staining around the chimney inside
If you look after a building like Knebworth Primary and Nursery School, tracing a leak on a big roof starts with where the water appears and works back.
What to check before booking
- What the survey won’t cover
- Whether you can ask questions once you have the report
- Which parts of the roof they’ll actually see
- What insurance they carry
Questions from Knebworth
Will you come out to Knebworth?
We do. A small place gets exactly the same survey as a big one, with the route planned beforehand.
Is Knebworth in the area you cover?
We do. The survey and report are the same in Knebworth as anywhere else, and visits run on weekdays and weekends.
Do you climb onto every roof?
Only when it is safe. Some roofs are too steep or fragile to walk on safely. We use safe viewpoints, the loft space and a drone where it applies.
What’s the best way to book?
Just phone 07833 053749 or use the contact form. We will ask a few questions, confirm the price and agree a date, weekday or weekend.
How long have you been surveying roofs?
We’ve completed more than 5,000 surveys, across 20+ years of surveying roofs.
Is thermal imaging part of a leak investigation?
We use thermal imaging where it helps, and it’s part of the Premium Survey. It shows temperature differences, not water itself, so anything it suggests is checked with moisture readings.
Why is the stain in a different place from the leak?
Water rarely drops straight down. It can follow a timber or the underlay a long way first, so the entry point is often well away from the mark. That is why we trace the route rather than patching above the stain.
How we price roof leak investigations
We confirm the price for your survey before you book. These are the things that affect it:
- How tall the building is and how easy the roof is to see
- The number of roofs, including extensions and garages
- Which survey package you book
- Commercial roofs and larger buildings
Roof leak investigation starts from £150, including VAT. What you pay depends on the size and height of the roof, how it can be seen safely and the package you choose.
Getting in touch
What helps most when you contact us:
- The property’s address and postcode
- What kind of property and roof it is
- Any marks or damp showing indoors
- Photos of the roof, taken safely from the ground or a window
To get a price for roof leak investigations in Knebworth, phone 07833 053749 or use the contact form. A few details about the property and the roof help us price the survey accurately.