Feltham · Greater London
Roof Lanterns in Feltham
Old polycarbonate lanterns in Feltham that leak, rattle or have yellowed can usually be replaced with a double glazed aluminium lantern on a sound upstand.
- TW14
- TW13
- TW4
- Guide from £1,095
Roof lanterns across Feltham
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.
Cutting a new opening for a roof lantern or skylight usually means trimming joists or rafters, so the roof can carry the load around the hole. Building regulations approval is generally needed for a new rooflight, covering structure, energy performance and, near a boundary, fire performance.
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.
What a typical job includes
- Sealed double glazed units with laminated inner pane options
- Removal and disposal of an old lantern or skylight
- Fixing, glazing and sealing onto the prepared upstand
- Survey of the roof, opening, upstand and drainage

Working in Feltham
- Postcodes covered
- TW14, TW13, TW4 and the surrounding area, including Hanworth, Ashford (Surrey) and Hounslow
- Coast
- Feltham is well inland, around 54 km from the nearest coast, so salt exposure is not usually a factor.
- Daylight and sun
- In Feltham 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
- Getting a large lantern onto a terraced flat roof may mean carrying it through the house or lifting it over neighbouring property, so access is planned at survey. Lanterns near a boundary raise fire performance questions, and conservation areas may restrict raised glazing.
- 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 Feltham
| 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
Listed buildings in England need listed building consent for most changes to historic windows or glass, and conservation areas can restrict changes visible from the street. Speak to the council's conservation officer before ordering.
What you can choose
Frame colours
Powder-coated aluminium in grey, black, white or other RAL colours, often dual colour to suit the roof and the room.
Opening vents
Manual or electric vents in the lantern or skylight, with optional rain sensors that close them automatically in wet weather.
Square or octagonal lantern
A pyramid or eight-sided design that suits square rooms, orangeries and spaces where a central focal point is wanted.
Roof Lanterns in Feltham: questions
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.
Can I replace my old polycarbonate roof lantern with glass?
Yes, in most cases. A glass lantern is heavier than polycarbonate, so the upstand and roof structure must be able to carry it. If the upstand is sound, level and the right size, a new aluminium lantern can usually sit on it. If not, the upstand is rebuilt first, which the survey will identify.
Does fitting a roof lantern need building regulations approval?
A new roof lantern or skylight generally needs building regulations approval, because the roof structure is cut and must be supported, and the unit must meet energy standards. Fire performance also matters near a boundary. Replacing a lantern on an existing sound upstand is simpler, and we explain which route applies at survey.
Do I need planning permission for a roof lantern?
Sometimes. In England, rooflights on a house are usually permitted development if they project no more than 150mm above the roof plane and are no higher than the highest part of the roof. Raised lanterns often exceed that, and flats, listed buildings and conservation areas have extra controls, so check with your council first.
Do you cover Feltham for roof lanterns?
Yes. We can quote for roof lanterns across Feltham and the surrounding Greater London area, including postcode districts TW14, TW13 and TW4, and nearby Hanworth, Ashford (Surrey) and Hounslow. 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 Feltham
Free survey for new glazing, clear guide prices and one point of contact for every glazing job.