- Price per m²
- £75–£132
- Typical life
- 30–60 years
- Manufacturer guarantees
- 15-year material, up to 25-year system guarantees
- 30 m² roof
- £3,050–£5,500
County Londonderry at a glance
- Largest towns
- Derry/Londonderry, Coleraine, Limavady, Magherafelt
- Postcode areas
- BT
- Building control
- Derry City and Strabane District Council, Causeway Coast and Glens Borough Council and Mid Ulster District Council
- Neighbouring areas
- County Tyrone · County Antrim · County Armagh · Belfast
- Guide price region
- Northern Ireland (−12% on West Midlands rates)
How much does mastic asphalt roofing cost in County Londonderry?
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 |
|---|---|
| Mastic asphalt roof (30 m²), scaffold | £3,050–£5,500 |
| Localised patch repair | £130–£440 |
| 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 Londonderry?
Flat roofs in County Londonderry sit on shops with flat-roofed rear stores below flats, lock-up garage blocks on estates and newer estates where the first extension roofs are now being replaced. 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 Londonderry the application goes to Derry City and Strabane District Council, Causeway Coast and Glens Borough Council and Mid Ulster District Council. More on the rules.
Is mastic asphalt still a good choice, or should I switch systems?
Mastic asphalt is still a good choice on concrete roofs, heritage and older buildings, and roofs that carry heavy foot traffic or plant. On lightweight timber roofs, garages and most modern extensions, another system is usually more practical.
Benefits: very long typical life; jointless and fully bonded; takes foot traffic well, especially with a paving finish; matches the original roof on many older buildings; local repairs blend into the existing surface.
Drawbacks: heavy, so the structure must be able to carry it; higher cost; needs specialist labour and hot works with molten material; can crack in cold if not well maintained, and softens in strong sun without a reflective finish.
If the structure is lightweight or the budget tight, torch-on felt or EPDM are common replacements. A compatible liquid-applied system can sometimes be laid over sound asphalt. On larger roofs, single-ply may be considered, and GRP suits smaller roofs needing a hard finish. Our repair or replace guide helps with the decision.
Which towns in County Londonderry do we cover?
Mastic asphalt roofing in County Londonderry: questions
Which towns in County Londonderry do you cover?
All of County Londonderry. 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 mastic asphalt roofing cost in County Londonderry?
£3,050–£5,500 for a 30 m² mastic asphalt roof including scaffold, 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 Londonderry?
It depends on where the roof is: in County Londonderry that's Derry City and Strabane District Council, Causeway Coast and Glens Borough Council and Mid Ulster District 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.
Why are mastic asphalt roofs painted silver or white?
The reflective coating keeps the asphalt cooler in sun, reducing softening and slowing the surface ageing that leads to crazing. It usually needs renewing every few years as part of maintenance.
Is mastic asphalt the same as tarmac?
No. Both contain bitumen, but mastic asphalt is a dense, voidless mix with fine limestone aggregate, made to be fully waterproof, while road surfacing is a different material.
Is mastic asphalt suitable for a balcony or terrace?
Yes, asphalt is traditionally used on terraces and walkways because it takes foot traffic well, often with paving on top. A new balcony or terrace generally needs planning permission, so check before converting a roof.
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