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Rooflights in flat roofs across Somerset

We build and waterproof rooflight upstands across Somerset as part of new and replacement flat roofs. Each upstand is insulated, built to the rooflight or lantern maker's sizes and finished with waterproofing that rises around 150 mm above the roof. You get a fixed written price after the free survey.

Rubber membrane being dressed up the timber upstand of a new flat rooflightComputer-generated example image
Guide price
£3,100–£5,400
Survey
Free for new and replacement roofs
Quote
Fixed, in writing
Coverage
England, Wales, Scotland, NI

Somerset at a glance

Largest towns
Bath, Weston-super-Mare, Taunton, Yeovil
Postcode areas
BA, BS, TA
Building control
Bath & North East Somerset Council, North Somerset Council and Somerset Council
Neighbouring areas
Bristol · Wiltshire · Gloucestershire · Dorset
Guide price region
South West (+3% on West Midlands rates)

How much does a rooflight upstand cost in Somerset?

Guide prices including VAT at South West 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£3,100–£5,400
Extension (20 m²), EPDM, new deck + insulation£2,900–£5,050
Extension (20 m²), EPDM with sedum green roof£4,550–£8,350

Which flat roofs are common in Somerset?

Flat roofs in Somerset sit on lock-up garage blocks on estates, 1960s and 1970s link-detached houses with flat-roofed garages and porches and low-rise post-war blocks of flats. The South West averages roughly 1,260 mm of rain a year and many roofs face wind off the Atlantic, so we specify fixings and edge details for wind uplift as well as drainage. Approximate 1991–2020 regional averages based on Met Office data.

Building regulations in England

Replacing more than half of a roof over a heated room usually counts as renovating a thermal element, so it is insulated to current standards and notified to building control. Renovated roofs over heated rooms are insulated to around 0.16 W/m²K where that's feasible, and new extension roofs are built to 0.15 W/m²K. In Somerset the application goes to Bath & North East Somerset Council, North Somerset Council and Somerset Council. More on the rules.

Do rooflights in flat roofs need building regulations approval?

Usually, yes, for a new opening, because cutting through the roof and trimming joists is a structural alteration. Approval may also be needed because the roof itself is being re-covered.

New rooflights need to meet the energy efficiency standards for glazing, so that the unit doesn't become a weak point in an insulated roof. Many rooflights have a laminated inner pane, so that if the glass breaks it stays in place rather than falling into the room, which is worth asking for over kitchens, living spaces and stairs. Close to a boundary, the fire performance of the roof, including any rooflights, can matter under the fire safety rules.

Whether you need planning permission depends on the property and the unit. A raised lantern changes the roofline more than a flat rooflight, and listed buildings and conservation areas have stricter rules, which also differ between the four nations. We handle building control or building standards where it is needed. The building regulations page and the planning guide explain more.

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 Somerset do we cover?

Rooflights in flat roofs in Somerset: questions

Which towns in Somerset do you cover?

All of Somerset. 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 Somerset?

£3,100–£5,400 for a 20 m² insulated EPDM extension roof with one rooflight upstand, at South West guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.

Which postcode areas do you cover in Somerset?

All of Somerset, including the BA, BS, TA postcode areas. Send your full postcode and we'll confirm.

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.

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.

How high should a flat rooflight upstand be?

Usually at least 150 mm from the finished roof surface to the top of the waterproofing, so the joint stays above standing water. Some rooflight makers specify more.

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