4 October 2026Extensions
Replacing a Conservatory Roof in Jersey: Which Permissions You Need
Swapping a glass conservatory roof for a solid one in Jersey: why planning permission usually isn't needed, why bye-law permission is, and what changed.
On an unlisted Jersey house, you do not need planning permission to replace a conservatory roof — glass, polycarbonate, or a solid tiled roof. You do need building bye-law permission if the new roof could affect the structure, or if it has less glazing than the old one. Swapping glass for a solid roof does both.
That is the current position on the States’ replacement conservatory roofs tool.
What changed, and why you may have read otherwise
In 2016 the States published a notice saying planning permission was needed to re-roof a conservatory if the roof shape changed or if the tiles were anything other than natural slate or clay. That notice is still online, and it still comes up when you search.
The current permission tool does not ask about tiles at all. It asks two questions:
| Question | If the answer is yes |
|---|---|
| Is the property listed? | Planning permission needed |
| Is the work outside the domestic curtilage? | Planning permission needed |
Answer no to both, and you do not need planning permission — provided a condition on an earlier permission has not removed your permitted development rights. If the house was built or extended with planning permission, check the conditions on that decision before you assume.
This covers replacing the roof. If the project makes the conservatory bigger or taller, it is no longer a like-for-like roof replacement, and the size and height limits for conservatories and extensions apply instead.
Why the bye-laws still apply
The States’ rule is that you need bye-law permission to replace a conservatory roof “where the work could affect the structural stability of the conservatory or the amount of glazing or level of translucence of the roof is reduced.”
A solid roof triggers both halves of that.
Weight. A conservatory frame and base were designed to carry glass or polycarbonate. Tiles, battens, insulation and a plastered ceiling weigh considerably more. Whether the existing frame, walls and foundations can take it is a structural question, and it needs an answer before the roof goes on, not after.
Wind. A solid roof behaves differently in high winds. It has to be fixed down to resist uplift, and the frame has to take the load.
Heat and condensation. A solid roof is usually fitted to make the room warmer. Done without a proper insulation and ventilation design, it traps moisture. Condensation is the specific risk the States’ guidance has always singled out.
The part most people miss
Jersey’s bye-laws only treat a room as a conservatory if at least 75% of its roof and 50% of its walls are translucent. Replace the glass roof with a solid one and the room no longer meets that definition — under the bye-laws, it is now an extension.
That matters because the conservatory exemptions stop applying. A conservatory under 20 square metres, separated from the house by external-quality doors or windows, can avoid bye-law permission altogether. An extension cannot. So a small conservatory that never needed bye-law approval when it was built will need it once the roof is solid.
It also means the doors or windows between the room and the house are worth thinking about. Keep them, and the room can be heated separately. Take them out to open the room up to the house, and it needs bye-law permission whatever its size.
When planning permission is needed
Two cases, from the States’ tool:
- The house is listed. Any replacement roof needs planning permission. On a listed building, a solid roof on a conservatory is assessed for its effect on the historic building, and the design matters.
- The work is outside the domestic curtilage — that is, the conservatory stands on land that is not part of the house’s own plot.
And the third, which catches people: an earlier permission removed your permitted development rights. It is worth ten minutes on the planning register before you place an order.
What the bye-law application involves
On a conservatory roof replacement, the drawings need to show:
- that the existing frame, walls and base can carry the new roof, or how they will be strengthened
- the roof structure, and how it is fixed down against wind uplift
- the insulation and ventilation build-up, so the roof does not condense
- the thermal separation from the house, or the lack of it
Our structural engineering is done in-house, so the structural check and the roof design come from the same office. Gary Payn went further than a new roof and replaced his old conservatory with an insulated sunroom: “The drawings were clear, accurate, and submitted online with zero hassle.”
Before you sign with a roofing company
Ask whether the bye-law application is included in their price, and who is producing the structural information it needs. Some suppliers handle it. Some leave it to you. A solid roof fitted without bye-law permission is unauthorised work, and it surfaces on the searches when you come to sell.
If you are not sure where your conservatory stands, see our conservatory and orangery page, or book a free consultation and we will tell you before you commit.