Orangery Size Limit: What You Can Build Without Planning Permission in the UK
When you think of an orangery, a solid, brick-based extension with a glazed roof designed to bring light into a home while feeling like a room, not a greenhouse. Also known as glasshouse extension, it’s more than just a sunroom—it’s a permanent structure that adds value and living space to your property. But here’s the thing: you can’t just slap one on the back of your house and call it done. The orangery size limit isn’t arbitrary—it’s tied to UK building regulations and planning laws that protect neighborhoods from oversized, out-of-place additions.
Most people confuse orangeries with conservatories, but they’re different. A conservatory, a mostly glass structure with a lightweight frame, often used for growing plants or as a casual sitting area usually has over 75% glazing and sits on a low base. An orangery, a more substantial building with brick or stone walls, a flat or pitched roof with a central glazed section, and a more permanent feel feels like part of the house. That difference matters for planning rules. If your orangery is under 30 square meters, doesn’t extend beyond the rear wall by more than 4 meters (or 3 meters for terraced homes), and stays under 4 meters in height, you likely won’t need planning permission. But if you’re planning something bigger, or if your home is in a conservation area or listed building, you’re in a different zone entirely.
Height, materials, and position all play a role. Your orangery can’t be higher than the highest part of your existing roof. If you’re building near a boundary, you can’t go higher than 3 meters unless it’s more than 2 meters from the boundary. And don’t forget—your orangery can’t cover more than half the land around your original house. These aren’t suggestions. They’re rules enforced by local councils. Many homeowners get tripped up thinking, "It’s just a garden room," but if it’s got a solid base, proper insulation, and a fixed roof, it’s treated like an extension. That’s why so many people end up with fines or forced removals—they didn’t check the rules first.
What you’ll find in the posts below isn’t just a list of articles. It’s a practical toolkit. You’ll see real examples of how people have designed orangeries that fit within legal limits, what materials work best in British weather, and how to blend your new space with your existing home. There’s also a deep dive into the history of orangeries—why they were built in the first place to protect citrus trees—and how that old-school purpose still shapes modern design. Whether you’re thinking of a small, cozy orangery or a full-blown garden room, these posts help you avoid costly mistakes and build something that’s legal, beautiful, and worth the investment.