Dereham at a glance
- Postcode districts
- NR19
- Population
- about 19,256 (GeoNames)
- Council area
- Breckland Council
- Building approval
- Breckland Council building control, or a registered building control approver
- Nearest main town
- Norwich, about 16 miles
- Guide price region
- East of England (+5% on West Midlands rates)
Why choose a green roof in Dereham?
If you're replacing an old flat roof in Dereham, it's worth deciding whether to add sedum at the same time. If the structure can take it, that is the ideal moment, because the waterproofing is new and the green layers won't need lifting for a long time.
In a town like Dereham, flat roofs are commonly found on 1930s semis with flat-roofed garages and kitchen extensions or lock-up garage blocks on estates. 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 Dereham?
For Dereham 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 a green roof go on my existing flat roof?
Only if the existing waterproofing is sound, root-resistant or protected by a root barrier, and has plenty of life left. In most cases it makes more sense to lay a green roof as part of a replacement.
Once the sedum, substrate and drainage layers are down, the membrane underneath is hard to inspect and expensive to repair, because the green layers have to be lifted to get to it. Putting a green roof on an ageing covering risks paying for the greenery twice. Our repair or replace guide helps you judge whether your current roof is a sensible base.
As for planning, re-covering a house roof normally needs no application if its appearance doesn't change materially. Because a green roof does change how a roof looks, check with your council, especially for listed buildings, conservation areas and roofs that are easily seen. The planning guide has more.
What's included?
- Pre-grown sedum blankets laid and watered in
- Warm or inverted build-up to suit the roof
- Root-resistant membrane or separate root barrier
- Structural check of joists, deck and supports
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?
Green and sedum roofs in Dereham: questions
Do you cover Dereham?
Yes. Dereham is part of our Norfolk coverage, including postcode districts NR19. 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 Dereham?
Where the work needs approval it goes to Breckland 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 Dereham?
£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.
Does a green roof leak more than a normal flat roof?
No, as long as it is built correctly. The waterproofing beneath is what keeps water out, and the green layers protect it from sun and weather. The main risk is building it on a weak or ageing membrane.
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.