Barnet · Greater London
Roof Lanterns in Barnet
Looking for a roof lantern or skylight in Barnet? We can quote for rectangular, square and octagonal aluminium lanterns and framed flat-roof skylights.
- EN4
- EN5
- HA8
- N2
- N3
- N12
- Guide from £1,095
Flat roof skylight across Barnet
Warm, moist air rises and collects in a roof lantern, so condensation can form on cold winter mornings, especially over kitchens and bathrooms. Thermally broken frames, warm-edge spacers and good room ventilation reduce it, and opening vents in the lantern can release warm air in summer.
In England, a rooflight on a house is usually permitted development if it projects no more than 150mm beyond the roof plane and is no higher than the highest part of the roof. Raised lanterns often stand taller than that, so check with the council before ordering.
In England, Approved Document L sets a limiting U-value of 2.2 W/m²K for rooflights, calculated in the horizontal position, for both new and existing homes. A kerb or upstand built on site should achieve 0.35 W/m²K or better. Ask for the lantern's declared horizontal U-value, not a vertical figure.
Old polycarbonate or single glazed roof lanterns can be replaced with double glazed aluminium lanterns on the existing upstand, if the upstand is sound, level and the right size. Upstands that are rotten, uninsulated or out of level should be rebuilt first, which the survey identifies.
What a typical job includes
- Survey of the roof, opening, upstand and drainage
- Made-to-measure aluminium roof lantern or framed skylight
- Removal and disposal of an old lantern or skylight
- Fixing, glazing and sealing onto the prepared upstand

About Barnet for this job
- Postcodes covered
- EN4, EN5, HA8, N2, N3, N12, N20, NW4, NW7, NW11 and the surrounding area, including Potters Bar, Borehamwood and Finchley
- Coast
- Barnet is well inland, around 45 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Barnet the midwinter sun reaches about 15° above the horizon at noon, with roughly 7.6 hours of daylight, rising to about 62° and 16.4 hours in midsummer. Overhead glazing receives far more light than a wall window of the same size, especially when the sun is high in summer. South-facing lanterns may need solar-control glass, while low winter sun and north-facing rooms benefit from clear, high light-transmission low-E glass.
- Access and setting
- Rural roofs collect more leaves, moss and bird debris, so lanterns need clear upstand drainage and regular checks. Exposed sites see higher wind loads and driving rain, and older outbuildings may need the roof structure strengthening before a lantern is added.
- Rules in England
- Approved Document K requires safety glass in critical locations in England: glazing in doors and in side panels within 300 mm of a door, up to 1500 mm above floor level, and any glazing in walls or partitions up to 800 mm above floor level.
Guide prices in Barnet
| Typical job | Guide price inc VAT |
|---|---|
| Lantern 1500 × 1000 mm, fitted to a kerb | £1,395 – £1,795 |
| Lantern 2000 × 1000 mm | £1,695 – £2,095 |
| Lantern 3000 × 1500 mm | £2,795 – £3,695 |
| Flat glass rooflight 1000 × 1000 mm | £1,095 – £1,395 |
Get a guide price for your size
In England, replacing a whole window, roof window or glazed external door is building work. It has to be notified to building control, either by an installer registered with a competent person scheme such as FENSA or Certass, or through a building notice to the council. Replacing only the glass in an existing frame is a repair and is not notifiable.
Choosing your roof lanterns
Solar-control glass
Neutral or blue-tinted coatings that reduce heat build-up under south or west-facing lanterns while keeping daylight levels high.
Square or octagonal lantern
A pyramid or eight-sided design that suits square rooms, orangeries and spaces where a central focal point is wanted.
Rectangular hipped lantern
A long ridge with hipped ends, suiting most rectangular extensions and kitchens, sized to the opening and the room below.
Roof Lanterns in Barnet: questions
How do I clean a roof lantern?
Self-cleaning coated glass lets rain lift most dirt, but a rinse with clean water in long dry spells helps. Clean from a safe position at the roof edge or from a suitable platform, never by standing on the lantern. Wipe the inside glass with mild soapy water, and keep leaves clear of the upstand and roof outlets.
Will a roof lantern make my room too hot?
A roof lantern can add heat on sunny days, especially facing south or west, because overhead glass receives sun for much of the day. Solar-control glass, opening vents and blinds help keep the room comfortable. The glass is chosen at survey based on the lantern's size and orientation and how the room is used.
What guarantee comes with a roof lantern?
Manufacturer guarantees apply to the frame, coating and sealed units, and the terms are confirmed in writing. The upstand and roof covering may be covered separately, depending on who builds them. Guarantee terms for the installation are set out in writing with your quote, so you know exactly what is covered before going ahead.
Why does my roof lantern get condensation?
Condensation forms when warm, moist air from cooking, bathing or drying clothes meets the colder glass and frames at high level. Older single glazed or non thermally broken lanterns suffer most. Thermally broken frames, warm-edge spacers, extractor fans and opening vents reduce it. Some condensation on very cold mornings is normal and clears as the room warms.
Do you cover Barnet for roof lanterns?
Yes. We can quote for roof lanterns across Barnet and the surrounding Greater London area, including postcode districts EN4, EN5, HA8, N2 and N3, and nearby Potters Bar, Borehamwood and Finchley. Start with your postcode on the quote form and a glazier will arrange a free survey before giving you a written quote.
Get a written quote in Barnet
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.