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.
Homeowners in Derry/Londonderry usually consider a new flat roof for one of a few reasons: something has worn out, the house no longer suits the way they live, or they are getting it ready to sell. We visit, agree a specification and put a fixed price in writing. Most jobs like this take 1–3 days for most roofs, and we work across County Londonderry, including Strabane, Limavady and Coleraine.
- Guide price
- £1,700–£3,900 inc VAT
- Time on site
- 1–3 days for most roofs
- Postcodes
- BT48
- Planning rules
- Northern Ireland
- Local area
- Derry
- Survey
- Free, with a written quote
What should you budget for a new flat roof in Derry/Londonderry?
Use the table to gauge the cost of a new flat roof in Derry/Londonderry 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 Derry/Londonderry |
|---|---|---|
| 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
- 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
- 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
- New trims, outlets and gutter connections
- Rooflights refitted or replaced where required
Homes in County Londonderry
Derry has Georgian and Victorian terraces around its walled city, alongside large post-war estates and newer developments. Coleraine, Limavady and Magherafelt mix older town centres with semis and estates, Portstewart has seaside villas, and rural areas have many detached homes and bungalows, often roughcast.
Terraces suit loft conversions and rear extensions, while rural bungalows commonly take extensions, loft rooms and driveways. Roughcast homes often need re-rendering, and coastal houses need roofline and window renewal.
Building traditions across County Londonderry also raise conservation and planning questions, so we check those for a new flat roof in Derry/Londonderry at the survey stage.
Permissions for a new flat roof in Derry/Londonderry
Homes in Derry/Londonderry come under the regulations for Northern Ireland, summarised below. We don't rely on general rules alone: we confirm the position for your address with the council before a quote goes out.
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.
The four stages
We look at the job
First, someone visits your home in Derry/Londonderry to see the space, take measurements and note anything that could affect the work, such as access or the condition of what is there. There is no charge for this visit.
Price and scope agreed
We turn the survey notes into a written quote. The price is fixed for the specification we agree, and the document sets out materials, scope and payment stages in plain language.
Dates and permissions
Before anyone starts, we confirm the programme in writing, check whether consents are required and arrange deliveries. If a skip or scaffolding on the road needs a permit, we apply for it.
Build and hand over
Work goes ahead as scheduled and you deal with one contact throughout. When the last trade leaves, we clear and clean the site, talk you through what has been done and pass on any certificates and care instructions.
Working with SK Home Improvements
Frequently asked questions
Can I stay at home during the work?
In most cases, yes. Most people can live at home throughout, and we plan the work to keep disruption down by protecting floors, agreeing working hours and keeping access routes clear. Bigger jobs affecting kitchens, bathrooms or heating may mean a short spell with reduced facilities, and we talk this through with you at the survey.
How much does a new flat roof cost?
Re-covering a typical 15–25m² extension or garage roof costs £1,700–£3,900. As a guide, allow around £75–£170 per square metre plus fixed costs for stripping, waste and access, with torch-on felt at the lower end and GRP or EPDM with new decking or insulation at the top. Small dormer and porch roofs cost less overall but more per square metre. We confirm a fixed price after the survey.
Which is better, EPDM rubber or GRP fibreglass?
EPDM rubber and GRP fibreglass are both reliable modern flat roof systems. EPDM is a single flexible sheet with very few joints, which copes well with movement and suits most extensions and garages. GRP is a hard, seamless finish that copes better with foot traffic and complex shapes, but needs dry weather to apply. Felt costs less but usually lasts less long. We recommend a system after seeing your roof.
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.
How long will a new flat roof take?
On a typical home, allow 1–3 days for most roofs. Larger projects, older buildings and extra work found once things are opened up can extend that, while simpler jobs may be shorter. Your quote includes an estimate of time on site, and your point of contact keeps you updated on the programme as the work progresses.
Nearby towns
Whether you're in the centre of Derry/Londonderry or on its outskirts, BT48 addresses are covered. We extend the same service, and the same fixed-price approach, to Strabane, Limavady and Coleraine.