- Guide price
- £2,450–£4,300
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
County Down at a glance
- Largest towns
- Bangor, Newtownards, Newry, Banbridge
- Postcode areas
- BT
- Building control
- Ards and North Down Borough Council, Newry, Mourne and Down District Council, Armagh City, Banbridge and Craigavon Borough Council and 1 other council
- Neighbouring areas
- Belfast · County Antrim · County Armagh · County Tyrone
- Guide price region
- Northern Ireland (−12% on West Midlands rates)
How much does a warm roof upgrade cost in County Down?
Guide prices including VAT at Northern Ireland 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 | £2,450–£4,300 |
| Extension (20 m²), EPDM with sedum green roof | £3,900–£7,100 |
Which flat roofs are common in County Down?
Flat roofs in County Down sit on low-rise post-war blocks of flats, newer estates where the first extension roofs are now being replaced and 1930s semis with flat-roofed garages and kitchen extensions. Northern Ireland averages roughly 1,150 mm of rain a year, spread over many wet days, so a roof that sheds water quickly to clear outlets lasts far longer than one that holds puddles. Approximate 1991–2020 regional averages based on Met Office data.
Building control in Northern Ireland
In Northern Ireland, renovating or replacing a roof over a heated room usually means meeting Technical Booklet F1, and building control should be contacted before work starts. Technical Booklet F1 sets roof insulation at 0.18 W/m²K when a roof over a heated room is renovated or newly built, where feasible. In County Down the application goes to Ards and North Down Borough Council, Newry, Mourne and Down District Council, Armagh City, Banbridge and Craigavon Borough Council and 1 other 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 County Down do we cover?
- Bangor
- Newtownards
- Newry
- Banbridge
- Dundonald
- Holywood
- Downpatrick
- Comber
- Carryduff
- Warrenpoint
- Newcastle
- Donaghadee
Warm roof insulation upgrades in County Down: questions
Which towns in County Down do you cover?
All of County Down. 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 County Down?
£2,450–£4,300 for a 20 m² extension roof in EPDM with a new deck and insulation, at Northern Ireland 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 County Down?
It depends on where the roof is: in County Down that's Ards and North Down Borough Council, Newry, Mourne and Down District Council, Armagh City, Banbridge and Craigavon Borough Council and 1 other council. In Northern Ireland, renovating or replacing a roof over a heated room usually means meeting Technical Booklet F1, and building control should be contacted before work starts. We confirm which applies at the survey.
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.
Will a warm roof make my room warmer?
Usually, yes. A room under a poorly insulated flat roof loses less heat once the roof is upgraded and tends to feel more even in temperature. How much difference you notice depends on how the roof was built before.
Can you insulate a flat roof from inside instead?
It is possible, but insulating between or under the joists creates a cold roof, which needs ventilation and carries a higher condensation risk. When the roof is being re-covered anyway, a warm roof from above is usually the better option.
Everything about warm roof insulation upgrades → · All flat roofing in County Down →