- Price per m²
- £79–£123
- Typical life
- 10–25+ years by product
- Manufacturer guarantees
- 10, 15 or 20-year guarantees by named system
- Typical garage roof
- £1,800–£2,850
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 a liquid-applied roof 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 |
|---|---|
| Single garage (18 m²), liquid-applied | £1,800–£2,850 |
| Balcony (12 m²), liquid-applied, scaffold | £1,650–£2,850 |
| 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 terraced streets with flat-roofed rear kitchens and bathrooms, 1960s and 1970s link-detached houses with flat-roofed garages and porches 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.
When is a liquid roof the best option, and when is it not?
A liquid roof is often the best option for roofs crowded with pipes, vents and upstands, for balconies and walkways, and for overlaying a structurally sound roof that is starting to fail. It is the wrong choice when the deck is rotten, the insulation is wet or the falls are badly wrong.
Advantages: continuous finish with no laps; forms details around pipes and odd shapes easily; cold-applied with no flame; can often go over felt, asphalt or concrete; some systems take foot traffic.
Disadvantages: higher cost per square metre than felt or EPDM; needs dry weather and careful thickness control; only as good as the surface it is bonded to; product quality varies widely across the market.
For a straightforward re-roof on a fresh deck, EPDM or GRP may offer better value. Larger flat areas suit torch-on felt or single-ply. On a sound mastic asphalt roof, a compatible liquid system can sometimes be applied over it. See also our guide to overlay or strip.
Do building regulations apply if a liquid coating goes over my roof?
They can. In England, Wales and Northern Ireland, re-covering more than half of a roof over a heated room is usually renovation of a thermal element, even when the new membrane goes over the old, so the roof should be insulated towards the renovation standard where feasible; for a Scottish property, the local building standards team will confirm whether a warrant is required.
A minor coating repair to a small area is different from re-covering the whole roof. Where insulation is needed, an overlay is not always practical, because the insulation has to go under a new waterproof layer. In that case we may recommend stripping to the deck, fitting a warm roof and applying the liquid system on top. Where approval applies, we deal with the paperwork; details are on the building regulations page.
Which towns in County Londonderry do we cover?
Liquid-applied 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 a liquid-applied roof cost in County Londonderry?
£1,800–£2,850 for a typical 18 m² garage roof in a liquid-applied system, 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.
What is a fleece-reinforced liquid roof?
It is a liquid membrane with a polyester fleece embedded between coats. The fleece adds strength, helps control thickness and resists cracking where the surface moves slightly.
Can liquid roofing stop a leak on a flat roof?
It can, if the leak is at a detail or the membrane is worn but the roof beneath is sound. If water has soaked the insulation or deck, coating over it will not cure the problem.
How long does a liquid roof take to cure?
That depends on the product and the weather. Some systems are rain-resistant within an hour or so, others take longer, and full cure can take a day or more in cool weather.
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