Flat RoofingContractors

Upgrades

Rooflights in flat roofs across Belfast

Planning a new flat roof with a rooflight in Belfast? Choosing the unit early helps. We build the upstand to suit it, insulate it to match the roof, and dress the waterproofing to the maker's details. We don't sell rooflights or lanterns as a product, but we fit them properly as part of the roof.

Rubber membrane being dressed up the timber upstand of a new flat rooflightComputer-generated example image
Guide price
£2,650–£4,600
Survey
Free for new and replacement roofs
Quote
Fixed, in writing
Coverage
England, Wales, Scotland, NI

Belfast at a glance

Largest towns
Belfast
Postcode areas
BT
Building control
Belfast City Council
Neighbouring areas
County Down · County Antrim · County Armagh · County Tyrone
Guide price region
Northern Ireland (−12% on West Midlands rates)

How much does a rooflight upstand cost in Belfast?

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

JobGuide price inc VAT
Extension (20 m²), EPDM, insulation + 1 rooflight upstand£2,650–£4,600
Extension (20 m²), EPDM, new deck + insulation£2,450–£4,300
Extension (20 m²), EPDM with sedum green roof£3,900–£7,100

Which flat roofs are common in Belfast?

Flat roofs in Belfast sit on 1960s and 1970s link-detached houses with flat-roofed garages and porches, low-rise post-war blocks of flats and 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. 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 Belfast the application goes to Belfast City Council. More on the rules.

Why is my flat rooflight leaking, and should it be repaired or replaced?

Most rooflight leaks come from the upstand detail rather than the glass: the membrane has split or pulled away at a corner, the upstand is too low, or the flashing at the top has failed. Repair the detail if the unit and the roof around it are sound.

Drips on the inside of the upstand in cold weather may be condensation rather than a leak, especially on older, uninsulated kerbs or single-glazed domes. Warm, moist air from a kitchen or bathroom meets the cold surface and condenses.

If the roof covering is near the end of its life, it is usually better to rebuild the upstand properly as part of a replacement, ideally with a new insulated kerb, rather than patching the old detail. Our repair or replace guide and flat roof repairs page cover the options.

How long does a rooflight upstand last?

A properly built, insulated upstand with waterproofing dressed to the maker's details should last as long as the roof covering around it. The rooflight's own seals and opening parts may need attention sooner.

Upstands fail early when they are too low, poorly insulated or built on a deck that moves. Keeping the area around the rooflight clear of leaves and debris, checking the corners after storms from a safe position and cleaning the glazing gently all help. Never lean on or stand on a rooflight: most are fragile, and the roof around them should be treated as fragile too. The maintenance guide covers routine checks.

Which towns in Belfast do we cover?

Rooflights in flat roofs in Belfast: questions

Which towns in Belfast do you cover?

All of Belfast. 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 rooflight upstand cost in Belfast?

£2,650–£4,600 for a 20 m² insulated EPDM extension roof with one rooflight upstand, 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 Belfast?

It depends on where the roof is: in Belfast that's Belfast City 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.

Can I walk on a flat rooflight?

No, unless it is a unit specifically designed and rated for foot traffic. Treat standard rooflights and the roof around them as fragile.

Can a lantern go on a warm roof?

Yes. The upstand is built and insulated to the full height of the warm roof build-up, so the lantern sits at the right level above the finished surface.

Do you supply rooflights and lanterns?

We fit rooflights and lanterns as part of a flat roof job, but we don't sell them as a separate product. If you've chosen a unit, we'll build the upstand to suit it.

Everything about rooflights in flat roofs → · All flat roofing in Belfast →

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