Rectangular roof lanterns in Dorchester
Whether your Dorchester extension is still on paper or the roof is already on, we can price a rectangular roof lantern to suit it. Standard sizes cost less and arrive sooner; made-to-measure fits a kerb that is already built.
Price a rectangular roof lantern for Dorchester
Postcode and kerb size first, then your details. We reply with a fixed written quote.
Rectangular roof lanterns for Dorchester homes
The classic double-hipped lantern: a ridge, four sloping sides and the most size choice.
On the shortest day Dorchester gets about 7h 57m of daylight, with the sun only 15.8° above the horizon at noon. Light from the sky overhead is the brightest available in winter, which is exactly what a roof lantern collects.
- The most size options of any lantern shape
- Standard sizes or made to your kerb
- Suits kitchen-diners and rear extensions
Delivery and fitting in Dorchester
Delivery to DT1 is quoted for your postcode and arrives on pallets at the kerbside, so plan enough people to unload.
Need it fitted? Send your postcode and we will confirm whether we have fitting cover in Dorchester before quoting.
Delivery to DT1 is standard mainland delivery, priced for your postcode and confirmed in writing before you order.
Rectangular roof lantern prices for Dorchester
What rectangular roof lanterns cost in common sizes (guide, inc VAT, supply only):
| Kerb size | Roof area | Guide price | Configure |
|---|---|---|---|
| 1000 × 1500 mm | 1.50 m² | £1,295–£1,495£1,079 ex VAT from | Configure |
| 1000 × 2000 mm | 2.00 m² | £1,495–£1,795£1,246 ex VAT from | Configure |
| 2000 × 3000 mm | 6.00 m² | £3,195–£3,695£2,662 ex VAT from | Configure |
| 2000 × 4000 mm | 8.00 m² | £4,095–£4,795£3,412 ex VAT from | Configure |
Guide prices include VAT at 20%, supply only, aluminium with self-cleaning double glazing in a stock colour. Your fixed price is confirmed in writing on your quote before you order.
Planning and building regulations for Dorchester
England's Approved Document L caps the U-value of new or replacement rooflights in existing homes at 2.2 W/m²K, calculated with the glass horizontal.
Planning-wise, a lantern on a new extension is judged as part of that extension, while one added to an existing roof can fall outside permitted development if it stands more than 150 mm proud.
Building regulations in Dorchester are checked by your local authority building control team or a registered building control approver. Replacing a rooflight in an existing home is building work. Installers registered with a competent person scheme can self-certify; otherwise building control must be involved.
Sources: Approved Document L, GOV.UK · Planning Portal
Questions from Dorchester
Which way should the ridge run?
The ridge runs along the longer side. On a square opening there is no ridge and the lantern becomes a pyramid.
What is the most common rectangular roof lantern size?
Sizes of 1000 × 2000 mm and 1500 × 2500 mm are common standard sizes for kitchen and dining extensions, but the right size is the one that matches your kerb. If your kerb is not built yet, our sizes guide helps you pick a standard size first.
Is it worth having solar-control glass in Dorchester?
With the midsummer sun about 62.7° high at noon, roof glass in Dorchester gets strong summer sun. Solar control is recommended for large or south-facing lanterns.
Do you deliver roof lanterns to Dorchester?
Yes. Delivery to Dorchester (DT1) is quoted for your exact postcode and confirmed in writing on your quote, together with the lead time.