Single-ply membrane roofing across County Down

Price per m²

£79–£128

Typical life

25–35+ years

Manufacturer guarantees

20–25 year guarantees on specified systems

Typical garage roof

£1,800–£2,950

How much does a single-ply roof cost in County Down?

Guide prices including VAT at Northern Ireland rates. The fixed price comes after a free survey for new and replacement roofs.

Which flat roofs are common in County Down?

Flat roofs in County Down sit on lock-up garage blocks on estates, shops with flat-roofed rear stores below flats and 1930s semis with flat-roofed garages and kitchen extensions. 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 Down the application goes to Ards and North Down Borough Council, Newry, Mourne and Down District Council, Armagh City, Banbridge and Craigavon Borough Council and 1 other council. More on the rules.

Is single-ply the right system for my roof?

Single-ply is usually the right system for medium and large flat roofs, such as shops, offices, units, surgeries, clubs and blocks, where speed of installation, light weight and long life matter. On a small domestic roof it can work well, though it is not always the most economical choice.

In its favour: lightweight; quick to lay over large areas; flame-free, as the seams are welded with hot air; long typical life; welded details at rooflights and plant; lighter-coloured membranes reflect more sunlight.

Against it: only one waterproof layer, so welding quality is critical; can be punctured by foot traffic or dropped tools without walkway protection; PVC needs separating from bitumen; repairs need compatible material and welding equipment.

For a small garage or extension, EPDM is often simpler. Where people walk regularly, GRP or a liquid system may be tougher. A multi-layer torch-on felt roof gives built-in redundancy, and on older buildings mastic asphalt may be the original material. Our commercial flat roofing page covers larger jobs.

What insulation and approvals does a single-ply re-roof need?

On a heated building, a full single-ply re-roof usually triggers the thermal-element rules, so insulation should be brought towards the renovation standard where feasible. In England that is 0.18 W/m²K for non-domestic and 0.16 W/m²K for domestic roofs, with Wales and Northern Ireland setting their own figures; Scottish roofs follow Section 6 of the building standards, and the council confirms whether a building warrant is required.

Single-ply suits a warm roof well, and tapered insulation can correct poor falls at the same time. A thicker build-up raises the roof, so we check upstand heights, door thresholds and rooflight kerbs at survey. Near boundaries, the external fire classification of the tested build-up can matter. We handle building control or building standards where needed; see the building regulations page.

Which towns in County Down do we cover?

• Bangor
• Newtownards
• Newry
• Banbridge
• Dundonald
• Holywood
• Downpatrick
• Comber
• Carryduff
• Warrenpoint
• Newcastle
• Donaghadee

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