Lisburn at a glance
- Postcode districts
- BT17, BT26, BT27, BT28
- Population
- about 77,506 (GeoNames)
- Council area
- Lisburn and Castlereagh City Council
- Building approval
- Lisburn and Castlereagh City Council building control
- Nearest main town
- Belfast, about 7 miles
- Guide price region
- Northern Ireland (−12% on West Midlands rates)
When should a flat roof in Lisburn be replaced?
A mineral felt roof laid decades ago may still look intact from the ground in Lisburn, yet have lost its chippings, cracked at the laps and pulled away at the upstands. Those faults let water track under the covering, so by the time a ceiling stain appears, the deck has often been wet for some time.
Lisburn's flat roofs are mostly on terraced streets with flat-roofed rear kitchens and bathrooms, with plenty on 1960s and 1970s link-detached houses with flat-roofed garages and porches too. 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.
How much does a flat roof replacement cost in Lisburn?
Guide price in Lisburn: £2,450–£4,300 for a 20 m² extension roof in EPDM with a new deck and insulation, 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 |
| Single garage (18 m²), torch-on felt | £1,350–£2,300 |
| Extension (20 m²), GRP, new deck + insulation | £2,650–£4,750 |
| Single garage (18 m²), EPDM rubber | £1,400–£2,450 |
Which system should I replace my flat roof with?
The right system depends on the roof's size, shape, use and number of details, so no single material suits every roof. These are the usual starting points:
- EPDM rubber suits simple, rectangular roofs, where one sheet can often cover the area with few or no joins.
- GRP fibreglass suits roofs with many corners, rooflights or edges, and gives a rigid surface for occasional maintenance traffic.
- Torch-on felt is a layered, hard-wearing system that keeps the cost down on larger or plain roofs.
- Liquid-applied systems handle awkward details and can overlay a sound existing surface.
- Single-ply and mastic asphalt are more usual on commercial roofs, blocks and terraces.
We recommend a system at survey and explain why. Our EPDM vs GRP vs felt guide sets out the trade-offs if you want to compare first.
What's included?
- Building control handled where needed, plus a written workmanship guarantee
- New deck, firrings and warm-roof insulation where needed
- Fixed written quote listing the full build-up
- Free survey of the deck, falls, edges and insulation
Building control in Northern Ireland
In Northern Ireland, Technical Booklet F1 sets roof insulation at 0.18 W/m²K when a roof over a heated room is renovated or newly built, where that's feasible. The district council's building control should be contacted before work starts, and we prepare the details it asks for. More on the rules.
Which nearby areas do we also cover?
Flat roof replacement in Lisburn: questions
Do you cover Lisburn?
Yes. Lisburn is part of our County Antrim coverage, including postcode districts BT17, BT26, BT27, BT28. Surveys and roofs are carried out by vetted roofing teams working under S&K Property Investments and Improvement Ltd.
Who checks building regulations for a flat roof in Lisburn?
Where the work needs approval it goes to Lisburn and Castlereagh City Council building control. We tell you at the survey whether your job needs it and deal with the paperwork as part of the quote.
How much does a flat roof replacement cost in Lisburn?
£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.
Will a replacement make my roof higher?
Usually a little, if insulation is added above the deck. We check door thresholds, window sills, upstands and wall flashings at survey so the new level works.
Will a new flat roof be better insulated than the old one?
If it is over a heated room, yes. A full replacement usually has to be upgraded towards current insulation levels where feasible, and we build it as a warm roof with the insulation above the deck.