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.
We take on a new flat roof throughout Lisburn and the surrounding BT17, BT27 and BT28 postcodes, as well as in Belfast, Castlereagh and Newtownabbey. The guide range for this work in Northern Ireland is £1,700–£3,900 including VAT; where your project falls depends on its size, the materials you pick and how easy the site is to reach. A free survey turns that range into a fixed figure.
- Guide price
- £1,700–£3,900 inc VAT
- Time on site
- 1–3 days for most roofs
- Postcodes
- BT17, BT27 and BT28
- Planning rules
- Northern Ireland
- Local area
- County Antrim
- Survey
- Free, with a written quote
Flat roofs prices in Lisburn
Use the table to gauge the cost of a new flat roof in Lisburn before we visit. Figures include VAT and are scaled for Northern Ireland, coming out about 14% below the national guide, which gives £1,700–£3,900 overall. After a free survey, you receive a fixed written price.
| Type of job | What it usually involves | Guide in Lisburn |
|---|---|---|
| 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 |
The main things that change the figure:
- Roof area and access to the roof
- Covering system: EPDM, GRP or torch-on felt
- Condition of the deck and joists underneath
- Insulation upgrades and changes to roof height at edges
Scope of the work
- Stripping and disposal of the old roof covering
- Replacement of rotten or soft deck boards
- Insulation upgrade to a warm roof build-up where agreed
- Upstands, flashings and drip edges finished neatly
- New trims, outlets and gutter connections
- Rooflights refitted or replaced where required
Building in Lisburn
Belfast has long rows of red-brick Victorian terraces, Edwardian villas in the north and south of the city and large post-war estates, while towns such as Ballymena, Antrim, Larne and Carrickfergus mix terraces, semis and newer developments. Dark basalt appears in older rural buildings, and pebbledash or roughcast is a very common finish.
The north coast and glens are exposed to strong winds, salt and frequent rain, which affects render, roofline and outdoor work.
None of this holds for every street in Lisburn, which is why we look at your actual house before pricing a new flat roof rather than assuming from its age alone.
Planning and building rules in Lisburn
For anyone in Lisburn, the relevant framework is Northern Ireland's. The summary below is general, so we always contact the council about your address before putting a price in writing.
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.
How does the job run?
Free site survey
Book a visit and we'll come to you. The survey covers measurements, the state of what's there now and any obvious constraints, so the price that follows is based on your actual home, not an average.
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.
Booking the work
We handle the paperwork side: checking whether planning permission or building control approval is needed, submitting applications where they are, and scheduling the trades and materials around your dates.
Finish and handover
The job proceeds in the order set out in the programme, with dust and debris kept under control. Finally we tidy away, inspect the work together and pass the finished project over to you with its paperwork.
What you can expect from us
Flat roofs in Lisburn: questions
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.
Do you cover Belfast, Castlereagh and Newtownabbey?
Yes. As well as Lisburn, we cover Belfast, Castlereagh and Newtownabbey and the rest of County Antrim. 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.
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.
Why does water sit on my flat roof?
Ponding water on a flat roof is usually caused by inadequate falls, sagging joists, a deck that has dipped or blocked outlets. Small puddles that dry within a day or two are not always a problem, but standing water speeds up wear and finds any weakness. A new roof can be laid on firring strips or tapered insulation to create proper falls. We check falls during the survey.
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.
Nearby towns
Whether you're in the centre of Lisburn or on its outskirts, BT17, BT27 and BT28 addresses are covered. We extend the same service, and the same fixed-price approach, to Belfast, Castlereagh and Newtownabbey.