Ampthill at a glance
- Postcode districts
- MK45
- Population
- about 20,026 (GeoNames)
- Council area
- Central Bedfordshire Council
- Building approval
- Central Bedfordshire Council building control, or a registered building control approver
- Nearest main town
- Bedford, about 8 miles
- Guide price region
- East of England (+5% on West Midlands rates)
Why choose a green roof in Ampthill?
In a place like Ampthill, many people look out over a flat extension or garage roof from upstairs. Grey felt or rubber isn't much of a view, and a sedum roof turns it into something green that changes colour through the seasons and flowers in summer.
Ampthill's flat roofs are mostly on 1930s semis with flat-roofed garages and kitchen extensions, with plenty on low-rise post-war blocks of flats too. The East of England is the driest part of Britain, with parts of the Anglian region around 630 mm a year, so summer heat and UV, not rainfall, do most of the ageing on a felt roof.
How much does a green roof cost in Ampthill?
For Ampthill we use East of England rates: £4,650–£8,500 is the guide for a 20 m² insulated extension roof finished as a sedum green roof, VAT included. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM with sedum green roof | £4,650–£8,500 |
| Extension (20 m²), EPDM, new deck + insulation | £2,950–£5,150 |
Can my flat roof take the weight of a green roof?
Not every roof can, which is why we check the structure before quoting. A sedum roof is light compared with an intensive garden, but its growing medium holds water, and a saturated build-up adds significant weight to the roof.
We look at the joist sizes, spans and spacing, the condition of the deck and what the roof sits on. On a recently built extension with generously sized joists, an extensive green roof may be straightforward. On an older garage or a roof with undersized or rotten timbers, the structure may need strengthening, or a structural engineer's calculation may be needed before we can go ahead.
In England, a new roof covering that adds 15% or more to the weight of the roof triggers building control approval, and a green roof will often fall into that category. We handle building control where it is needed. The building regulations page covers the approval routes in each nation.
What's included?
- Drainage layer, filter and lightweight growing medium
- Gravel strips kept clear around edges and outlets
- Structural check of joists, deck and supports
- Root-resistant membrane or separate root barrier
Building regulations in England
Replacing more than half of a flat roof over a heated room usually counts as renovating a thermal element, so the roof is insulated to around 0.16 W/m²K where that's technically and economically feasible, and the work is notified to building control: the council or a registered building control approver, unless a registered competent person self-certifies it. A roof on a new extension is built to 0.15 W/m²K. Patch repairs, and most unheated detached garages, don't trigger the upgrade. Structural changes, or a new covering that adds 15% or more to the roof's weight, also need approval. More on the rules.
Which nearby areas do we also cover?
- Kempston · 6 mi
- Bedford · 8 mi
- Dunstable · 10 mi
- Leighton Buzzard · 10 mi
- Bletchley · 10 mi
- Hitchin · 10 mi
Green and sedum roofs in Ampthill: questions
Do you cover Ampthill?
Yes. Ampthill is part of our Bedfordshire coverage, including postcode districts MK45. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Ampthill?
Where the work needs approval it goes to Central Bedfordshire Council building control, or a registered building control approver. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a green roof cost in Ampthill?
£4,650–£8,500 for a 20 m² insulated extension roof finished as a sedum green roof, at East of England guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Can I walk on a green roof?
Only for maintenance, and only where it is safe. Most extensive green roofs on homes aren't designed as roof terraces, and a terrace generally needs planning permission and edge protection.
What happens if a green roof needs repairing?
The green layers are lifted around the problem area, the membrane is repaired, and the layers are relaid. Building on a sound, long-life membrane in the first place keeps that to a minimum.