Being in a conservation area does not stop you building a garden room. It removes two
specific permitted development rights. Both are easy to design around if you know about
them at the start, and expensive to discover halfway through.
The two things that change
1. You cannot build to the side of the house
Outside a conservation area you can put an outbuilding to the side, behind the front wall. Inside
one, that right is removed. The building has to go behind the house.
2. Larger buildings far from the house lose their rights
A building of more than 10 square metres sited more than 20 metres from
the house is no longer permitted development. For most terrace gardens this never comes up,
because 20 metres is a long garden. For larger plots in Dulwich it genuinely does.
What does not change
The height limits are the same. The 50 percent garden coverage rule is the same. The requirement
that the use is incidental to the house is the same. Conservation area status is narrower in its
effect than most people assume.
Trees are the thing people forget
In a conservation area, trees have protection whether or not they carry a Tree Preservation
Order. You generally have to give the council notice before doing work to a tree, and that includes
excavation close enough to damage roots. On a plot with mature trees this can steer the whole
design, and it is a strong argument for ground screws over a concrete slab.
How to check your own address
- Look your address up on the council’s planning map to confirm whether you are in a conservation
area and whether an Article 4 direction applies, which can remove permitted
development rights entirely. - Check whether the building is listed. If it is, you need listed building consent
for work in the curtilage. - Consider a Lawful Development Certificate. In a conservation area this is worth
more than usual, because the rules are less obvious and a future buyer’s solicitor will ask.
Our fuller guide to garden room planning permission in Southwark covers the permitted development limits in detail.
We check all of this at the site visit, before design work starts. You can see how it plays out
across our garden building project gallery, from garden room builders in South London to garden art and music studios.
Frequently asked questions
Can you build a garden room in a conservation area?
Yes. Conservation area status removes two permitted development rights: you cannot build to the side of the house, and a building over 10 square metres sited more than 20 metres from the house loses its rights. Everything else is unchanged.
Do I need planning permission for a garden room in a conservation area?
Not automatically. If the building sits behind the house, within the height limits, and is not more than 20 metres away, it is normally still permitted development.
Are trees protected in a conservation area?
Yes. Trees in a conservation area have protection whether or not they carry a Tree Preservation Order, and you generally have to notify the council before carrying out work near them.
How do I find out if I am in a conservation area?
Look your address up on your council’s planning map. Southwark and Lambeth both publish theirs online.
Thinking about a garden building?
We design and build bespoke garden rooms and studios, purpose built garden offices, garden art and music studios, garden yoga and exercise studios and bespoke garden sheds and storage across East Dulwich, Dulwich, Peckham and the surrounding South London areas. See our garden building project gallery or the project map of every build, then book a free site visit and we will give you an honest estimate with no obligation.
General guidance, not planning advice. Confirm your own position with your local planning
authority before you build.