- Guide price
- £2,950–£5,150
- Survey
- Free for new and replacement roofs
- Quote
- Fixed, in writing
- Coverage
- England, Wales, Scotland, NI
Derbyshire at a glance
- Largest towns
- Derby, Chesterfield, Long Eaton, Ilkeston
- Postcode areas
- DE, NG, S, SK
- Building control
- Derby City Council, Chesterfield Borough Council, Erewash Borough Council and 4 other councils
- Neighbouring areas
- Nottinghamshire · Staffordshire · South Yorkshire · Leicestershire
- Guide price region
- East Midlands (−2% on West Midlands rates)
How much does a rooflight upstand cost in Derbyshire?
Guide prices including VAT at East Midlands 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 | £2,950–£5,150 |
| Extension (20 m²), EPDM, new deck + insulation | £2,750–£4,800 |
| Extension (20 m²), EPDM with sedum green roof | £4,300–£7,900 |
Which flat roofs are common in Derbyshire?
Flat roofs in Derbyshire sit on newer estates where the first extension roofs are now being replaced, terraced streets with flat-roofed rear kitchens and bathrooms and 1930s semis with flat-roofed garages and kitchen extensions. The East Midlands is drier than the west of Britain, so most flat roofs here fail through age, UV and poor detailing at upstands rather than sheer rainfall. 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 Derbyshire the application goes to Derby City Council, Chesterfield Borough Council, Erewash Borough Council and 4 other councils. More on the rules.
Should I choose a fixed or an opening rooflight, or a lantern?
Choose a fixed rooflight if you only want daylight, an opening one if the room needs ventilation, and a lantern if you want a raised, pitched glazed feature over a larger space.
- Fixed flat rooflights are the simplest and usually the cheapest option. They have the fewest moving seals, and the upstand detail is straightforward.
- Opening rooflights can be manual or electric, and electric units often include a rain sensor that closes them automatically. They need a power supply planned in before the ceiling is finished. Some are designed as hatches to give access to the roof.
- Roof lanterns have a framed, pitched glazed top that brings in more light and adds height to the room. They are heavier and larger, so the upstand has to be strong, level and square, and the joists around the opening may need strengthening.
Whatever you choose, it helps to settle on the unit before the roof is built, so the upstand can be made to the maker's sizes. If you've already chosen one, we build the upstand to suit it.
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 Derbyshire do we cover?
- Derby
- Chesterfield
- Long Eaton
- Ilkeston
- Swadlincote
- Staveley
- Belper
- Heanor
- Alfreton
- Dronfield
- Ripley
- Buxton
- New Mills
- Glossop
- Sinfin
Rooflights in flat roofs in Derbyshire: questions
Which towns in Derbyshire do you cover?
All of Derbyshire. 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 Derbyshire?
£2,950–£5,150 for a 20 m² insulated EPDM extension roof with one rooflight upstand, at East Midlands guide rates including VAT. The fixed price comes after a free survey for new and replacement roofs.
Which postcode areas do you cover in Derbyshire?
All of Derbyshire, including the DE, NG, S, SK postcode areas. Send your full postcode and we'll confirm.
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.
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.
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.
Everything about rooflights in flat roofs → · All flat roofing in Derbyshire →