- Guide price
- £2,600–£4,550
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Northumberland at a glance
- Largest towns
- Blyth, Cramlington, Ashington, Bedlington
- Postcode areas
- NE
- Building control
- Northumberland County Council
- Neighbouring areas
- Tyne and Wear · County Durham · North Yorkshire · Cumbria
- Guide price region
- North East (−7% on West Midlands rates)
How much does a warm roof upgrade cost in Northumberland?
Guide prices including VAT at North East rates. 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 | £2,600–£4,550 |
| Extension (20 m²), EPDM with sedum green roof | £4,100–£7,500 |
Which flat roofs are common in Northumberland?
Flat roofs in Northumberland sit on terraced streets with flat-roofed rear kitchens and bathrooms, newer estates where the first extension roofs are now being replaced and 1930s semis with flat-roofed garages and kitchen extensions. England averages roughly 870 mm of rain a year; the North East is drier than the west but cold and windy near the coast, so wind uplift and freeze-thaw are in the specification. Approximate 1991–2020 regional averages based on Met Office data.
Building regulations in England
Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Northumberland the application goes to Northumberland County Council. More on the rules.
Can a cold flat roof be converted to a warm roof?
Yes, and it is the usual approach when an older cold roof is re-covered. The old covering is stripped, the deck is checked and replaced where needed, and the vapour control layer, insulation and new waterproofing go on top.
The existing insulation between the joists is assessed at the same time. Leaving it in place can create a cold, unventilated gap that traps moisture, so it is often removed or the build-up is designed so that most of the insulation sits above the deck. We decide this case by case once we can see inside the roof. If the covering is still sound and you are only patching it, the upgrade isn't usually required, and our repair or replace guide explains how to decide between the two.
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.
Which towns in Northumberland do we cover?
Warm roof insulation upgrades in Northumberland: questions
Which towns in Northumberland do you cover?
All of Northumberland. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a warm roof upgrade cost in Northumberland?
£2,600–£4,550 for a 20 m² extension roof in EPDM with a new deck and insulation, at North East guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which council handles building control for a flat roof in Northumberland?
It depends on where the roof is: in Northumberland that's Northumberland County Council. Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. We confirm which applies at the survey.
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.
Does a warm roof stop condensation?
It greatly reduces the risk by keeping the deck warm and placing a vapour control layer on the warm side. Good ventilation in kitchens and bathrooms below still helps.
Is there VAT relief on flat roof insulation?
Don't count on it. Insulation fitted as part of a roof replacement is usually treated as part of a single standard-rated job. Check your own case with HMRC guidance or an adviser.
Everything about warm roof insulation upgrades → · All flat roofing in Northumberland →