Derry/Londonderry at a glance
- Postcode districts
- BT48
- Population
- about 87,153 (GeoNames)
- Council area
- Derry City and Strabane District Council
- Building approval
- Derry City and Strabane District Council building control
- Guide price region
- Northern Ireland (−12% on West Midlands rates)
Why choose torch-on felt roofing in Derry/Londonderry?
Where a flat roof in Derry/Londonderry already has a felt covering and the building owner wants like-for-like, torch-on is the natural replacement. The old roof is stripped, the deck checked and the new layers laid, often with warm-roof insulation added when the space below is heated.
In and around Derry/Londonderry, flat roofs are typically found on low-rise post-war blocks of flats, and on 1960s and 1970s link-detached houses with flat-roofed garages and porches. 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 torch-on felt roof cost in Derry/Londonderry?
For Derry/Londonderry we use Northern Ireland rates: £1,350–£2,300 is the guide for a typical 18 m² garage roof in torch-on felt, VAT included. 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 |
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.
What's included?
- Two- or three-layer reinforced bitumen membrane with staggered laps
- Hot-works checks and fire watch on every torch-on job
- Strip-off of the existing roof covering and removal of waste
- Mineral-finished cap sheet, upstands, outlets and edge trims
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?
Torch-on felt roofing in Derry/Londonderry: questions
Do you cover Derry/Londonderry?
Yes. Derry/Londonderry is part of our County Londonderry coverage, including postcode districts BT48. 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 Derry/Londonderry?
Where the work needs approval it goes to Derry City and Strabane District 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 torch-on felt roof cost in Derry/Londonderry?
£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.
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.
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.