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)
What does a dormer roof in Lisburn need?
High, exposed dormers in Lisburn take the full force of the wind and rain. Edge trims loosen, flashings lift and the felt at the drip edge cracks. Once the faults spread around the perimeter, a new roof with fresh trims usually lasts far longer than another round of repairs.
In and around Lisburn, flat roofs are typically found on 1930s semis with flat-roofed garages and kitchen extensions, and on terraced streets with flat-roofed rear kitchens and bathrooms. 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 new dormer roof cost in Lisburn?
For Lisburn we use Northern Ireland rates: £1,250–£2,350 is the guide for an 8 m² GRP dormer roof including scaffold, VAT included. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Dormer (8 m²), GRP, scaffold | £1,250–£2,350 |
| Single garage (18 m²), EPDM rubber | £1,400–£2,450 |
| Extension (20 m²), GRP, new deck + insulation | £2,650–£4,750 |
How long does a dormer roof replacement take?
The roofing itself typically takes one to three days, with scaffold going up before and coming down after. Allow a few extra days overall for the scaffold.
The room under the dormer stays usable, though it will be noisy during the strip-out, and dust can fall through gaps around the ceiling. Moving furniture away from the window helps. Scaffold usually needs space on the drive or garden, and sometimes a pavement licence. GRP has a strong smell while it cures, so keep the dormer windows shut on the day it is laid.
What's included?
- Scaffold with edge protection, priced in the quote
- Written workmanship guarantee, with building control handled where needed
- Warm-roof insulation and a vapour control layer
- Strip-out of the old covering and deck repairs
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?
Dormer roofs 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 new dormer roof cost in Lisburn?
£1,250–£2,350 for an 8 m² GRP dormer roof including scaffold, at Northern Ireland guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
How long does a GRP dormer roof last?
As an indicative range, GRP lasts 20–40 years with good specification and maintenance.
Is a dormer roof cheaper than a garage roof?
Not by as much as the size suggests. Scaffold and the extra detailing at height mean a small dormer roof often costs about the same as a single garage roof.