- Price per m²
- £53–£92
- Typical life
- 15–25 years
- Manufacturer guarantees
- 10–20 year material guarantees on specified systems
- Typical garage roof
- £1,350–£2,300
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 torch-on felt 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 |
|---|---|
| Single garage (18 m²), torch-on felt | £1,350–£2,300 |
| Extension (20 m²), felt, new deck + insulation | £2,400–£4,100 |
| Block of flats (150 m²), felt + insulation + scaffold | £13,700–£23,950 |
| Single garage (18 m²), EPDM rubber | £1,400–£2,450 |
| Extension (20 m²), EPDM, new deck + insulation | £2,450–£4,300 |
Which flat roofs are common in County Antrim?
Flat roofs in County Antrim sit on terraced streets with flat-roofed rear kitchens and bathrooms, low-rise post-war blocks of flats and lock-up garage blocks on estates. 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 does a torch-on felt roof last, and what is the guarantee?
A modern torch-on roof typically lasts 15 to 25 years, and high-performance systems with better membranes can last longer. That is a big step up from older felt roofs, which were often single-layer, unreinforced or poorly bonded.
What shortens the life of a felt roof is usually visible: mineral chippings worn away so the bitumen is exposed to sunlight, blisters where moisture was trapped, split laps, and upstands that have slumped or pulled away from the wall. Ponding speeds all of this up.
Manufacturer material guarantees are available on many specified torch-on systems; they often depend on a particular build-up and registration, which we handle where the system allows. Every re-roof also comes with our written workmanship guarantee, the length of which is stated in the quote, and insurance-backed options can be discussed. Our flat roof lifespan guide compares felt with the other systems.
Is torch-on roofing safe, and what is the difference between two- and three-layer systems?
Yes, torch-on is safe when hot works are properly controlled, because most roof fires linked to torching start at hidden timber or debris near edges and upstands, not on the open roof. Our teams follow a hot-works routine on every job:
- check eaves, fascias, soffits and wall cavities for timber, nests and debris before lighting a torch;
- use a cold-applied or self-adhesive membrane, rather than a flame, at edges, against combustible materials and in tight details;
- keep fire extinguishers on the roof and the gas bottles secured and away from the work;
- stop torching well before the team leaves, then carry out a fire watch so smouldering is spotted while people are still on site.
As for layers, a two-layer system (underlay plus cap sheet) is common on domestic roofs such as garages and extensions. A three-layer system adds an intermediate sheet, giving more thickness and redundancy, and is often specified on larger, commercial and multi-occupied roofs. The right choice depends on the size and use of the roof and the system's requirements, so we set it out in the quote.
Near a boundary, the external fire performance of the tested build-up, such as a BROOF(t4) classification, can also matter, and we check it where it applies.
Which towns in County Antrim do we cover?
Torch-on felt roofing 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 torch-on felt roof cost in County Antrim?
£1,350–£2,300 for a typical 18 m² garage roof in torch-on felt, 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.
Can torch-on felt be laid in wet weather?
Not in rain or on a wet deck, because moisture trapped under the membrane causes blisters. Light cold weather is usually workable, but we will postpone rather than lay on a damp surface.
Can I paint or coat an old felt roof?
Reflective or liquid coatings can extend the life of a sound felt roof, but they will not fix wet insulation, a rotten deck or poor falls. A survey shows whether coating or replacement makes more sense.
How long does it take to lay a torch-on felt roof?
A garage roof typically takes one to two days and an insulated extension two to three. Larger roofs and blocks are phased over longer, with each area made weathertight before the team leaves.
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