- Guide price
- £2,450–£4,300
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
County Antrim at a glance
- Largest towns
- Lisburn, Newtownabbey, Carrickfergus, Ballymena
- Postcode areas
- BT
- Building control
- Lisburn and Castlereagh City Council, Antrim and Newtownabbey Borough Council, Mid and East Antrim Borough Council and 1 other council
- Neighbouring areas
- Belfast · County Down · County Armagh · County Londonderry
- Guide price region
- Northern Ireland (−12% on West Midlands rates)
How much does a new extension roof cost in County Antrim?
Guide prices 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 |
| Extension (20 m²), GRP, new deck + insulation | £2,650–£4,750 |
| Extension (20 m²), EPDM, insulation + 1 rooflight upstand | £2,650–£4,600 |
| Single garage (18 m²), EPDM rubber | £1,400–£2,450 |
Which flat roofs are common in County Antrim?
Flat roofs in County Antrim sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, 1930s semis with flat-roofed garages and kitchen extensions and 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. Approximate 1991–2020 regional averages based on Met Office data.
Building control in Northern Ireland
In Northern Ireland, renovating or replacing a roof over a heated room usually means meeting Technical Booklet F1, and building control should be contacted before work starts. Technical Booklet F1 sets roof insulation at 0.18 W/m²K when a roof over a heated room is renovated or newly built, where feasible. In County Antrim the application goes to Lisburn and Castlereagh City Council, Antrim and Newtownabbey Borough Council, Mid and East Antrim Borough Council and 1 other council. More on the rules.
How long will my kitchen be disrupted by a new roof?
Most single-storey extension roofs are replaced in two to four working days, depending on size, rooflights and weather. The kitchen usually stays in use throughout.
Expect noise during the strip-out, and occasional dust through gaps around old rooflights, so it helps to cover worktops and move anything fragile off high shelves. We strip only what we can make weathertight by the end of each day. If a rooflight or lantern is being lifted and refitted, there may be a temporary cover over the opening for a short time. Resin systems smell while they cure, so keep the windows below the roof closed on that day.
Which towns in County Antrim do we cover?
Extension and kitchen roofs in County Antrim: questions
Which towns in County Antrim do you cover?
All of County Antrim. The main towns have their own pages below, and if yours isn't listed we still cover it: send your postcode and we'll confirm.
How much does a new extension roof cost in County Antrim?
£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.
Which council handles building control for a flat roof in County Antrim?
It depends on where the roof is: in County Antrim that's Lisburn and Castlereagh City Council, Antrim and Newtownabbey Borough Council, Mid and East Antrim Borough Council and 1 other council. In Northern Ireland, renovating or replacing a roof over a heated room usually means meeting Technical Booklet F1, and building control should be contacted before work starts. We confirm which applies at the survey.
How do I know my extension roof needs replacing rather than repairing?
Repeated leaks, a soft deck, wet insulation or widespread cracking point to replacement. A single defect on a dry, sound roof can usually be repaired.
Is EPDM or GRP better for a kitchen extension?
Neither is better in every case. EPDM suits simple rectangular roofs with few details, while GRP is often chosen where there are rooflights, corners or occasional foot traffic.
Can a sedum roof go on my extension?
Possibly, if the structure can carry the extra weight and the roof has suitable falls and drainage. We check the joists at survey before recommending it.
Everything about extension and kitchen roofs → · All flat roofing in County Antrim →