Hertfordshire · London and the South East
Harmer Green Roof Leak Investigation
Find out what’s going on with the leaking roof before you spend money on it. Roof leak investigations in Harmer Green, with photographs and a clear written report.
- Stains around a skylight
- Leaks below a flat extension roof
- Ceiling stains that grow after rain
Questions from Harmer Green
Is my home in Harmer Green listed or in a conservation area?
Start with Historic England’s list for listing and your council for conservation areas. Either can affect what roof work is allowed, so it’s worth checking before planning any.
Is Harmer Green within the area you cover?
Yes. Harmer Green is within the area we cover, which takes in towns, villages and rural addresses. We survey roofs across London and the South East. Let us know about access, parking and anything unusual about getting there as you book.
Why does not the damp patch line up with the hole?
Because water travels. It runs along rafters, battens or underlay before it drips, so the entry point is frequently well away from the mark. That’s why we trace the route rather than patching above the stain.
Can every leak be traced?
Not always, and we’ll be honest about that. Some leaks hide well, especially those that need wind-driven rain. Where the source isn’t certain, we list the likely routes in order.
What insurance do you have?
Professional indemnity and public liability insurance cover our surveys. Ask if you need details for a managing agent or building owner.
Can you survey at the weekend?
Surveys run on weekdays, Saturdays and Sundays. To find a day that suits you, call 07833 053749 or use the contact form.
Does the investigation include the repair?
This service finds and reports the cause, and the repair is separate. With the report, a roofer knows exactly where to look.
Roof leak investigation in Harmer Green
Not every drip is a leak. Condensation in a cold, poorly ventilated loft can drip from nails and timbers, leaving marks that look just like rainwater. Knowing which it is means the right fix can be done, because they need very different work. We check the pattern of damp, the weather and the ventilation before reaching a view. Common reasons to book are staining where a gutter or parapet meets the wall and leaks that appear only in driving rain, across rooflights and dormers, valleys and parapet gutters and lead flashings.
For a small place like Harmer Green, the inspection is the same as anywhere: we simply plan the journey and access ahead. It helps to know where the water appears, in what weather, and what you’ve seen outside, plus any earlier repairs. If you have photographs of the water coming in, they help as well.
Most points in the report come with a picture, because a photo of a cracked flashing says more than a paragraph. Anything out of sight on the day is listed as such.
- Where
- Harmer Green (AL6)
- Wider area
- Hertfordshire
- Price
- From £150 inc. VAT
- Report
- A written report with photos, by email
- Appointments
- Monday to Sunday, daytime
- Cover
- PI and public liability insurance
- Telephone
- 07833 053749
- Page updated
- 27 October 2026
Places near Harmer Green
Also in Harmer Green
Common roof problems in Harmer Green
Flashings are one of the commonest sources of roof leaks. Lead or mortar closes the gap wherever a roof meets a wall, chimney or dormer. When lead lifts or splits, or a mortar fillet cracks, rain runs straight in.
Typical things we are asked to look at include:
- Damp on a chimney breast
- Stains around a skylight
- Damp underlay across a wide area
- A leak that comes and goes with the weather
Take an older house close to Digswell Village Church: old mortar, worn lead and slipped slates are the usual suspects when water gets in.
What to check before booking
- What’s outside the scope of the survey
- Their insurance cover
- Whether VAT is in the quoted price
- How they plan to inspect the roof safely
How the survey changes by roof type
Flat roof upstands and outlets
Each flat roof relies on its outlets to drain. When one blocks, water ponds and finds any weak spot. We check outlets and the covering around them.
Slate and tile slopes
Cracked mortar lets ridge and hip tiles move. Water then gets in along the top of the roof.
Tips from our surveys
Here are a few things we’d tell any owner, before and after a survey:
- Let us know about any past repairs to the roof
- Mention any plumbing above the damp area
- Record whether it leaks in every downpour or only some
- Make sure the loft is accessible
Any roofer you ask to quote can work from the report. The photos show the defects and where they are, so the repair is aimed at the cause.
Have leaves and moss cleared from gutters, valleys and outlets, particularly in autumn. Blocked outlets on parapet and flat roofs cause many leaks. Use a professional rather than climbing up yourself.
Harmer Green roofs and the weather
In this part of the South East, older roofs are mostly slate or clay tile and many newer ones concrete tile, with flat-roofed extensions, dormers and garages common everywhere. The covering and its details give the first clues when tracing where water is coming from. About 1.5 miles south-west lies Digswell House, a reminder of how long the area around Harmer Green has been built on. 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.
If you let a flat or house near Welwyn North station, a tenant living with a leak needs the cause found, not just the stain painted over. For businesses in and around places such as Howard Centre, a leak can close part of a shop or office, so finding the cause quickly matters.
Harmer Green is about 2 miles north of Welwyn Garden City, in Hertfordshire. Wherever you are in Harmer Green, we can carry out roof leak investigations at 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.
All of AL6 is covered for roof leak investigations. Other places close to Harmer Green include 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). Larger places within reach include 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).
Around Harmer Green
In Harmer Green, that means homes and buildings near Danesbury Park, Monk's Walk School and The White Horse Public House. For rail, the closest station is Welwyn North station, about 0.8 miles south-west of the centre. Nearby you’ll also find 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.
What we can’t see
Before booking, it is worth knowing what a survey will not do:
- Carrying out the fix
- Defects hidden under coverings or inside walls without opening up
- Leaks from plumbing, tanks or pipework rather than the roof
If in doubt, ring 07833 053749 or use the contact form and we will point you to the right survey before you book. What a survey covers and does not.
Roofs we survey in Harmer Green
- Slate and tile slopes
- The roof space
- Flat roof details
- Rooflights and dormers
- Valleys and parapet gutters
- Lead flashings
- Chimney stacks
How the survey works
A survey visit follows a simple order: we listen to what’s been worrying you, inspect the roof from every safe viewpoint, photograph what we find and make notes for the report. Most visits take about one to two hours on an ordinary house, or half a day or so for a commercial building. Somewhere like Harmer Green needs a little journey planning: let us know about lanes, gates and parking. On the day, we inspect whatever is safely visible, inside and out.
- We start with your notes and photos of the leak.
- Inside, we check the stain and the ceiling around it.
- From the loft 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
- Mention any parking restrictions on your street
- Note where any stains or damp appear
- For flats, check roof access has been agreed
Arrange a survey
When you’re ready to go ahead, call 07833 053749 or use the contact form. From there it’s a case of choosing a package, agreeing the price and fixing a day.
Related advice
Why it is worth a survey now in Harmer Green
If a leak has been ‘fixed’ before and has come back, the cause was probably missed. We look past the obvious spot and check each likely route. That’s often what breaks the cycle. For older village homes like those around Harmer Green, the right replacement materials are not always easy to find quickly. Spotting a problem early leaves room to find them.
Every price we give includes VAT. Our price is from £150, including VAT. We confirm the exact price before booking.
Why choose Independent Roof Survey in Harmer Green
- Over 20 years’ experience
- Visits on any day of the week
- Over 5,000 surveys carried out
- Prices that include VAT
Read what a roof survey costs or two real surveys.