- Guide price
- £3,100–£5,400
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Wiltshire at a glance
- Largest towns
- Swindon, Salisbury, Trowbridge, Chippenham
- Postcode areas
- BA, SN, SP
- Building control
- Swindon Borough Council and Wiltshire Council
- Neighbouring areas
- Bristol · Gloucestershire · Somerset · Dorset
- Guide price region
- South West (+3% on West Midlands rates)
How much does a rooflight upstand cost in Wiltshire?
Guide prices including VAT at South West rates. The fixed price comes after a free survey for new and replacement roofs.
| Job | Guide 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 Wiltshire?
Flat roofs in Wiltshire sit on bungalows with flat-roofed side extensions and dormers, 1960s and 1970s link-detached houses with flat-roofed garages and porches and 1930s semis with flat-roofed garages and kitchen extensions. 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 Wiltshire the application goes to Swindon Borough Council and Wiltshire 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.
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.
Which towns in Wiltshire do we cover?
Rooflights in flat roofs in Wiltshire: questions
Which towns in Wiltshire do you cover?
All of Wiltshire. 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 Wiltshire?
£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 council handles building control for a flat roof in Wiltshire?
It depends on where the roof is: in Wiltshire that's Swindon Borough Council and Wiltshire Council. 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. We confirm which applies at the survey.
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.
Why does my rooflight drip in winter?
If it only drips in cold weather and not when it rains, it is probably condensation on a cold, poorly insulated upstand or older glazing. Better ventilation helps, and an insulated kerb and modern unit usually fix it.
Can a rooflight be added to an existing flat roof?
Yes, if the structure allows it. The opening is cut, the joists are trimmed and an upstand is built and waterproofed into the existing covering. On an older roof, it is often better to do it as part of a replacement.
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