A flat roof replacement strips the old covering from a low-pitched roof and lays a new waterproof system, usually EPDM rubber, GRP fibreglass or torch-on felt, over a sound deck with correct falls, upstands, trims and outlets so rainwater drains away.
Cost is usually the first question about a new flat roof, so here is the guide for Northern Ireland: £1,700–£3,900 including VAT. We cover the whole of County Down, with Bangor, County Down, Castlereagh, Newtownards and Newry among the main centres. Because each UK nation sets its own rules, we check the requirements in Northern Ireland for your property, then put a firm price on paper following a free survey.
- Guide price
- £1,700–£3,900 inc VAT
- Time on site
- 1–3 days for most roofs
- Planning rules
- Northern Ireland
- Price level
- About 14% below the national guide
- Towns listed
- 5
- Survey
- Free, with a written quote
Flat roofs prices in County Down
Budgeting for a new flat roof in County Down? The numbers below include VAT and are adjusted for Northern Ireland, where costs are about 14% below the national guide. The headline range is £1,700–£3,900. Nothing is final until we have measured up at a free survey and agreed the specification with you.
| Type of job | What it usually involves | Guide in County Down |
|---|---|---|
| Small roof (up to 8m²) | A dormer, bay, porch or small garage roof re-covered in EPDM or GRP. | £700–£1,700 |
| Extension or garage (15–25m²) | A typical extension or single garage roof stripped and re-covered. | £1,700–£3,900 |
| Large or new warm roof | Larger roofs, or roofs needing a new deck and insulation build-up. | £3,400–£7,700 |
What moves the price up or down:
- Roof area and access to the roof
- Condition of the deck and joists underneath
- Insulation upgrades and changes to roof height at edges
- Number of rooflights, pipes and upstands to detail
Scope of the work
- Survey of the covering, deck, falls, upstands and drainage
- Replacement of rotten or soft deck boards
- Insulation upgrade to a warm roof build-up where agreed
- New EPDM, GRP or torch-on felt membrane laid to falls
- New trims, outlets and gutter connections
- Rooflights refitted or replaced where required
Housing across County Down
County Down takes in suburbs of Belfast, Bangor and Holywood with Victorian and Edwardian villas, and Newry, Downpatrick and Banbridge with older town centres and newer estates. Mourne granite appears in buildings around the mountains, and detached rural homes and bungalows are common across the county, often rendered or pebbledashed.
Villas and semis suit kitchen extensions, loft conversions and garden landscaping. Rural detached homes commonly take extensions and driveways, and rendered houses often need re-rendering, roofline renewal and window replacement.
Coastal areas such as the Ards Peninsula face salt and wind, and the Mournes bring heavier rain and colder conditions.
Do you need permission in County Down?
Because County Down falls under Northern Ireland's rules, the guidance below is the version relevant to you. Before sending a price, we check your property's position with the council.
In Northern Ireland, re-roofing with similar materials does not usually need planning permission outside listed buildings and conservation areas.
Significant re-roofing should be checked with building control under the Building Regulations (Northern Ireland). Bats are protected across the UK; if they roost under roof tiles, soffits or fascias, work stops and a licensed ecologist advises before it restarts.
Rules change and every property is different, so we check the planning history and constraints for your address before we quote.
From survey to handover
A visit to your home
A free survey comes first. It gives us what we need to price a new flat roof properly, including dimensions, existing materials and access for deliveries, and gives you the chance to ask anything you like.
Written quote
The quote arrives in writing, not over the phone. It covers the full scope, the finishes you've chosen, any exclusions and the payment schedule, with a fixed price tied to that specification.
Dates and permissions
Once you accept, we agree start dates, order materials and deal with any planning, building control or neighbour notices the job needs. You'll know who is coming and when before work begins.
On site to finish
Our trades complete a new flat roof while your point of contact keeps you updated. When everything is finished, we clear the site, take away waste and go through the result with you before handover.
What you can expect from us
Frequently asked questions
How long does a flat roof last?
A well-installed EPDM or GRP flat roof can last 25 years or more, while torch-on felt systems typically last around 15–25 years, depending on quality and exposure. Lifespan depends on correct falls, good detailing at edges and upstands, and keeping outlets clear. Foot traffic, ponding and poor ventilation shorten it. Annual checks help catch small problems early.
What happens at the survey?
We visit your home at a time that suits you, look at the area involved, take measurements and check access, condition and any services that might be affected. We talk through what you want from a new flat roof, explain the options and answer questions. There is no charge and no obligation; afterwards we send a written quote.
Can you repair my flat roof instead of replacing it?
A flat roof can often be repaired if the damage is limited to a small split, a failed joint or a loose upstand and the rest of the covering is sound. If the deck is soft, the covering is blistered or cracked across the roof, or leaks keep returning, replacement is usually better value. We assess the whole roof and give you an honest recommendation.
How long does a flat roof replacement take?
Replacing a typical extension or garage flat roof usually takes one to three days. Stripping and any deck repairs come first, then insulation where agreed, the new membrane and the trims and outlets. GRP needs dry weather and time to cure, and we plan around the forecast. Larger roofs or roofs with many rooflights take longer. We confirm timing with your quote.
Do you cover Bangor, County Down, Castlereagh and Newtownards?
Yes. As well as County Down, we cover Bangor, County Down, Castlereagh and Newtownards and the rest of County Down. Our coverage is UK-wide, so the process is the same wherever you are: a free site survey, a quote in writing that fixes the price for the agreed scope, and one point of contact while the work is planned and carried out.
Towns in County Down
Our coverage for a new flat roof in County Down includes the towns listed here. Each page explains guide costs, typical timings and the neighbouring places we also serve.