Outbuilding Planning Permission in London

Find out when outbuildings in London need planning permission, what permitted development allows for sheds, studios, and ancillary structures, and what constraints apply.

Outbuildings cover a wide range of structures: sheds, garden rooms, home offices, garages, annexes, and summer houses. Many can be built without planning permission under permitted development rights, but the height, footprint, position, and intended use all matter — and London's high density of conservation areas means many homeowners face additional restrictions.

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When it may be permitted development

These are the common features that keep a project on the simpler route.

The outbuilding is a single storey, has an eaves height no greater than 2.5 metres, and an overall height within the applicable limits for the roof type.
All outbuildings on the property together cover no more than 50% of the original garden, and the structure sits to the rear or side behind the principal elevation.
The outbuilding is used for purposes incidental to the enjoyment of the house — storage, home office, hobby space — rather than as a separate dwelling.

When planning permission is more likely

These are the usual triggers that push a scheme beyond straightforward PD rights.

The structure is designed or equipped to be used as a self-contained living unit with sleeping, cooking, and bathroom facilities.
The total outbuilding footprint across the property exceeds 50% of the original garden area, or the height limits are not met.
The property is in a conservation area and the outbuilding would be visible from a highway or public open space, or the property is listed and no listed building consent has been granted.

What CanUBuild checks

Faster answers before you speak to an architect or builder

The tool is designed to answer the first question most homeowners have: is this worth pursuing, and what is most likely to block it?

CanUBuild checks address-level constraints including conservation area status, listed building designation, Article 4 directions, and flood risk before you invest in plans.

The outbuilding workflow captures the dimensions, position, and use of the proposed structure so you understand whether it falls within permitted development.

You also see nearby planning decisions to gauge how your local planning authority has responded to similar outbuilding proposals in your area.

FAQ

Questions people ask before starting a project

Do I need planning permission for a shed or garden outbuilding?

Usually not, if the structure is reasonably sized, sits within the garden, and is used for purposes ancillary to the house. However, very large structures, properties in conservation areas, and listed buildings are common exceptions.

What is the 50% garden coverage rule for outbuildings?

Permitted development rules require that the combined footprint of all outbuildings and extensions does not cover more than 50% of the original garden area. This is measured against the garden as it existed when the house was first built.

Can I build an outbuilding close to my boundary?

Yes, but if any part of the outbuilding is within 2 metres of a boundary, the maximum overall height is restricted to 2.5 metres. This catches many compact garden structures that would otherwise comply.

Can I use an outbuilding as living accommodation?

Not under permitted development as a self-contained dwelling. Ancillary accommodation — a spare room for occasional guests — may be acceptable, but a structure with its own kitchen, bathroom, and sleeping space is treated as a new residential unit and requires planning permission.

Next step

Check your property before paying for drawings

Search for the address, choose your project type, and get a planning feasibility answer based on permitted development rules, constraints, and local precedent data.

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