Antrim at a glance
- Postcode districts
- BT41
- Population
- about 19,661 (GeoNames)
- Council area
- Antrim and Newtownabbey Borough Council
- Building approval
- Antrim and Newtownabbey Borough Council building control
- Nearest main town
- Belfast, about 14 miles
- Guide price region
- Northern Ireland (−12% on West Midlands rates)
Why choose a green roof in Antrim?
Garden rooms and outbuildings in Antrim, as elsewhere, often have small flat roofs that are seen from the house and garden. A sedum finish helps them blend in, provided the structure is strong enough and the roof underneath is built properly.
In and around Antrim, flat roofs are typically found on lock-up garage blocks on estates, and on bungalows with flat-roofed side extensions and dormers. 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 green roof cost in Antrim?
At Northern Ireland guide rates, a 20 m² insulated extension roof finished as a sedum green roof comes to £3,900–£7,100 including VAT. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide price inc VAT |
|---|---|
| Extension (20 m²), EPDM with sedum green roof | £3,900–£7,100 |
| Extension (20 m²), EPDM, new deck + insulation | £2,450–£4,300 |
How is a green roof built on top of a flat roof?
From the bottom up, a green roof is a deck, a waterproofing system with root protection, then drainage, filter, growing medium and plants. The waterproofing does the job of keeping water out. The green layers sit above it.
- Warm roof build-up: vapour control layer, insulation and waterproof membrane on the deck, then the green layers on top. This is the usual choice on a home extension being re-roofed.
- Inverted build-up: waterproofing on the deck, then insulation boards designed to sit above it, then the green layers. This is common on terraces and some commercial roofs.
- Root barrier: roots will exploit any weakness, so the membrane needs to be root-resistant. Some membranes are tested as root-resistant; others need a separate root barrier laid on top.
- Drainage and edges: a drainage layer carries surplus water to outlets, and a gravel or pebble strip is usually left around edges, outlets, upstands and rooflights to keep them clear and accessible.
Upstands still need to rise around 150 mm above the finished surface, which on a green roof means above the top of the growing medium. We check that at the survey, alongside the external fire performance of the build-up where the roof is close to a boundary.
What's included?
- Gravel strips kept clear around edges and outlets
- Structural check of joists, deck and supports
- Drainage layer, filter and lightweight growing medium
- Pre-grown sedum blankets laid and watered in
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?
- Ballyclare · 9 mi
- Ballymena · 10 mi
- Newtownabbey · 13 mi
- Belfast · 14 mi
- Lisburn · 15 mi
- Magherafelt · 16 mi
Green and sedum roofs in Antrim: questions
Do you cover Antrim?
Yes. Antrim is part of our County Antrim coverage, including postcode districts BT41. 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 Antrim?
Where the work needs approval it goes to Antrim and Newtownabbey Borough 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 green roof cost in Antrim?
£3,900–£7,100 for a 20 m² insulated extension roof finished as a sedum green roof, at Northern Ireland guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
What happens if a green roof needs repairing?
The green layers are lifted around the problem area, the membrane is repaired, and the layers are relaid. Building on a sound, long-life membrane in the first place keeps that to a minimum.
Do I need to water a sedum roof?
Usually only in the first season, during long dry spells, while the blankets establish. After that, sedum copes with dry weather well.