Letchworth Garden City at a glance
- Postcode districts
- SG6
- Population
- about 33,990 (GeoNames)
- Council area
- North Hertfordshire District Council
- Building approval
- North Hertfordshire District Council building control, or a registered building control approver
- Nearest main town
- Stevenage, about 5 miles
- Guide price region
- East of England (+5% on West Midlands rates)
Why upgrade to a warm roof in Letchworth Garden City?
In a place like Letchworth Garden City, homeowners usually think about insulation when the roof covering is worn out. That is the right moment, because the thermal rules normally apply to a replacement over a heated room, and adding insulation then costs far less than doing it separately later.
Around Letchworth Garden City, flat roofs are common on lock-up garage blocks on estates and on terraced streets with flat-roofed rear kitchens and bathrooms. 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 warm roof upgrade cost in Letchworth Garden City?
For Letchworth Garden City we use East of England rates: £2,950–£5,150 is the guide for a 20 m² extension roof in EPDM with a new deck and insulation, VAT included. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM, new deck + insulation | £2,950–£5,150 |
| Extension (20 m²), EPDM with sedum green roof | £4,650–£8,500 |
Do I have to insulate my flat roof when I replace it?
Usually, yes, if the roof is over a heated room and you are replacing more than half of its covering. In England, Wales and Northern Ireland, that counts as renovating a thermal element, so the roof should be upgraded to the renovation standard where that is technically, functionally and economically feasible.
The rules don't usually apply to patch repairs, or to an unheated, detached garage. The target U-value depends on where you live:
| Nation | Roof renovation target |
|---|---|
| England | 0.16 W/m²K (homes), 0.18 (non-domestic) |
| Wales | 0.16 W/m²K |
| Scotland | Section 6 framework, with a domestic benchmark of 0.12 W/m²K pursued as far as reasonably practicable |
| Northern Ireland | 0.18 W/m²K |
A new extension roof has a tighter target than a renovation: 0.15 in England and 0.13 in Wales. The economic test in England's guidance is a simple payback within 15 years. We handle building control or building standards where it is needed. The building regulations page sets out the approval routes in each nation.
What's included?
- Rigid insulation boards sized to the U-value target
- Upstands, trims and kerbs reset to the new roof level
- New waterproofing, with a written workmanship guarantee
- Building control or building standards handled where needed
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?
Warm roof insulation upgrades in Letchworth Garden City: questions
Do you cover Letchworth Garden City?
Yes. Letchworth Garden City is part of our Hertfordshire coverage, including postcode districts SG6. 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 Letchworth Garden City?
Where the work needs approval it goes to North Hertfordshire District 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 warm roof upgrade cost in Letchworth Garden City?
£2,950–£5,150 for a 20 m² extension roof in EPDM with a new deck and insulation, at East of England guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Is a warm roof worth it on a garage?
On a detached, unheated garage, usually not, as there is no heated space to protect and the thermal rules don't normally apply. On an integral or heated garage, or one being converted into a room, it is.
How thick does flat roof insulation need to be?
It depends on the insulation product and the U-value target. With common PIR boards, meeting a renovation target usually means well over 100 mm. Thinner, higher-performance boards are available where height is tight.