The answer
Yes, in almost every case. A new roof lantern means cutting an opening in the roof and carrying its edges and its weight on new framing. That changes the structure and the thermal performance of the roof, which is what the Building Regulations exist to control. Replacing an old lantern with a new one is also controlled work. It is separate from planning permission, so a lantern can need one approval and not the other. Where the work is notifiable, Building Control is told by us, through the council or a registered building control approver.
Why a lantern is controlled work
The Building Regulations in England are the national standards for how buildings are built and altered. They do not judge appearance, as planning does. They look at whether the work is safe, structurally sound and thermally sensible.
A roof lantern touches several of those at once. Cutting into a flat roof removes joists or rafters that carried load, and the new framing around the opening has to take it. The lantern adds its own weight and the wind and snow loads on it. The roof's insulation is interrupted by a large area of glass. And at the edges, water and fire both have routes that were not there before.
For these reasons a new lantern needs Building Regulations approval, and so does a replacement, which counts as controlled work for the glazing alone. Getting that approval works the same way either way, and we deal with it for you.
Planning is the other half. Whether a lantern needs planning permission depends on the house and how tall the lantern stands, as our page on planning permission for rooflights explains.
The parts of the regulations that apply
Four sets of rules do most of the work for a lantern. Under Part A (structure) the opening must be framed so that the load of the roof passes round it into the walls or beams. On an existing flat roof that often means new trimmers, and sometimes a steel lintel where a wide opening interrupts several joists.
Part L (energy) comes next. For an existing home, Approved Document L Volume 1, Table 4.2, sets rooflights a ceiling of 2.2 W/m²K, and a lantern is assessed on that basis. The figure covers the glazing and the frame together, and the glass specification does most of the work. The roof around the upstand must also be insulated to current standards.
Part B (fire) looks at how fire could spread through the roof and, for lanterns near a boundary, at the materials used. Position relative to a neighbour's wall can matter.
Part K (glazing and falls) says roof glazing must be safe where people may fall or walk on it, and it must be possible to clean or maintain it safely.
Ventilation can also come in. If the lantern serves a habitable room or forms part of a new extension, the room must still be properly ventilated, and an opening section can help with that.
The Building Control route
Work that is notifiable has to be reported to a Building Control body before it starts. There are two kinds. The local authority has its own Building Control team, and since April 2024 private bodies are called registered building control approvers. Either can do the job, and the result in law is the same.
The notification or application goes in with the details of the lantern and the roof. An inspector may visit to see the opening framed before it is closed, and again at completion. When the work is signed off, a completion certificate is issued, and you keep it.
The notification is ours to make, and we arrange the inspections around the fitting. You do not have to choose the route, chase the paperwork or be at home for every visit, though it helps to know when the framing is open.
The certificate matters later. When you sell, a buyer's solicitor will usually ask for evidence that building work was signed off. A lantern with no certificate can hold up a sale or lead to a request for retrospective approval, which is slower and harder than doing it properly at the time.
Is a replacement lantern different?
Replacing an existing lantern in the same opening feels like a smaller job, and in practice it is, but the regulations still apply. Replacement windows and rooflights are controlled work, so the new unit must meet the energy limit for its type.
That has a practical effect. Many older lanterns and domes have glazing well below today's standard, and the replacement will be a clear step up. In an existing dwelling the limit is 2.2 W/m²K for a rooflight, and a modern double or triple glazed unit with a thermal break meets it without difficulty.
Where the replacement keeps the same opening and the same upstand, the structural side is usually simple, and the main points for Building Control are the thermal figures and the fixing. Where the opening is enlarged or the kerb is raised, the structural checks return, and the job is closer to a new installation.
Either way the sequence is the same: survey, fixed written quote, then work with the notification handled. Our answer on putting a lantern on an existing flat roof goes through what a roof needs before it can take one.
Doing it without approval
It is tempting to treat a lantern as a rooflight upgrade and skip the paperwork, and some builders do. The risks fall on the owner.
Without sign-off, a council can ask for the work to be opened up for inspection and, if it fails, altered. There may be no evidence that the structure round the opening was framed to carry load, and no record that the glazing meets the energy limit. Insurers and lenders can ask questions, and a future sale can stall.
Doing it properly costs less than putting it right later. The notification, the inspection and the certificate are the paper trail showing the structure, the insulation and the glazing were checked, and a firm that handles them routinely finds the process light.
If you are weighing up quotes, it is reasonable to ask each firm who handles the Building Control notification and whether you will receive the completion certificate. We install to current Building Regulations and give a 10-year workmanship guarantee in writing, and the first step is a free survey. For how the glass is sized and specified, see roof lantern sizes and proportions, or read the roof lanterns page for the full picture.