Can a Roof Lantern Go on an Orangery Roof?

An orangery sits between a conservatory and an extension. It has solid brick or stone piers, large windows, and a flat roof with a lantern in the centre. Where a conservatory has a glass roof almost edge to edge, an orangery has a solid roof around the outside and glass only in the lantern.

That solid roof matters. It carries the structure, holds the insulation and gives a firm, level base for the lantern's upstand. Because of that, an orangery roof is well suited to a lantern. The load path is already designed in. The lantern's weight goes into joists, trimmers and the walls or piers below.

If your orangery already has a lantern, the question may be replacing it. If it has a flat roof with no lantern, or a plain rooflight, the question is adding one. Both start with the survey, where the structure and the roof build-up are checked.

For a new opening, the joists are cut and trimmed, a new upstand is formed, the roof is insulated and covered up to the upstand, and the lantern is fixed and sealed. The ceiling below is lined around the opening. Our guide to fitting into an existing flat roof covers the stages, and the work is the same in principle for an orangery.

Check the existing roof first

The age and condition of the covering matter. If it is nearing the end of its life, it can be sensible to renew it around the lantern while the roof is open, so that you do not disturb a new junction later. The survey will say what looks sound.

Some people have an older conservatory roof and ask whether it can become an orangery roof with a lantern. This is a larger job than adding a lantern. The glass or polycarbonate roof is removed, a new solid roof structure is built, insulated and finished, and a lantern is set into it. The existing walls must be able to carry the new load, and that is a structural question for the survey and, often, an engineer.

Done well, the result is a warmer room in winter and a cooler one in summer, because the solid roof insulates far better than the old covering. The lantern still gives the room daylight in the middle, and the edges are shaded.

Building Regulations

Altering the roof structure for a new rooflight is building work that the council, or a registered building control approver, has to approve. On a notifiable job we send in the notification. In an existing home the lantern has a ceiling of 2.2 W/m²K, being a rooflight. Replacing a roof can also bring other regulation questions, which the survey will raise.

Planning

Planning follows the usual rules for a house, with the conditions in our planning guide. Anything heritage-protected, or any flat, needs its own check with the council first.

The lantern sets the character of an orangery, so its size and style deserve thought. Proportion matters. It should look balanced against the roof around it, with a clear band of flat roof on all sides. Traditional orangeries often have a lantern with a gentle pitch and fine glazing bars, while modern ones may have a slimmer, flatter profile.

The glass matters too. A south-facing orangery with large windows and a lantern gets a lot of sun, and solar control glass is worth considering. Our guide to roof lantern glazing explains the choices. For size, read the lantern sizing guide. You will find a broader overview on the roof lanterns page.

When you are ready, ask for a free survey at #quote. We look at the roof, the structure and the spot below, and then give you a fixed written quote. The job carries a 10-year workmanship guarantee, in writing.