Curtilage and how its extent is decided

Curtilage has no statutory definition in planning law, which is awkward given how much rests on it. Class E of Part 1 of the General Permitted Development Order allows outbuildings incidental to the enjoyment of a dwellinghouse only within its curtilage. Put the garden office fifteen metres beyond the curtilage boundary and it stops being permitted development, whatever its size.

For a landlord or investor buying a house with land, the curtilage question decides what can be built without an application, how much of the plot can be covered, and occasionally whether an old outbuilding is listed.

Why curtilage controls permitted development

Several rights in Part 1 are expressed as applying within the curtilage. Class E covers buildings and enclosures required for a purpose incidental to the enjoyment of the dwellinghouse. Class F covers hard surfaces. Class A limits extensions by reference to the original dwellinghouse, and separately caps the proportion of the curtilage, excluding the ground area of the original house, that may be covered by buildings at 50 per cent.

That 50 per cent cap is where the extent of the curtilage does real work. Draw the curtilage tightly around the house and a modest outbuilding breaches the cap. Draw it around the whole paddock and almost nothing would. Councils know this, which is why a certificate application with an optimistic red line attracts questions.

The interaction with extension allowances is explored further in the article on how previous extensions count against your allowance.

The factors the courts apply

English courts have settled on three considerations, drawn from the Calderdale case in 1983 and applied ever since: the physical layout of the land and buildings, the ownership of the land past and present, and the use or function of the land past and present.

Physical layout carries the most weight in practice. Walls, hedges, fences, changes in surface treatment and the way access is arranged all tell an inspector where the domestic area stops. A post and rail fence separating mown lawn from grazed grass is a stronger indicator than any deed plan.

Ownership matters less than people expect. Buying the field next door does not bring it into the curtilage. Conversely, land in separate ownership can still form part of the curtilage if layout and function point that way.

Function asks whether the land serves the house in some necessary or useful manner, the formulation from the 1950 Sinclair-Lockhart's Trustees case. Grazing horses is not a domestic function. Hanging out washing, parking, sitting and storing garden tools are.

One older idea has been corrected. The suggestion in Dyer that curtilage must be small was qualified by the Court of Appeal in Skerritts of Nottingham in 2000, which accepted that a large house can have a large curtilage. Size alone does not decide it.

Gardens, paddocks and land beyond the domestic area

The common scenario is a house with a garden, then a gate, then a paddock. The paddock is almost always outside the curtilage, even where the same family has owned both for decades and the children ride ponies on it.

Two features usually settle it. First, whether the paddock is enclosed with the garden or separately. Second, whether it is managed as garden, meaning mown, planted and used for domestic purposes, or as agricultural or equestrian land.

Orchards, tennis courts and swimming pools sit in between. A tennis court laid out as part of the garden, accessed only through the garden, generally falls inside. A field with goalposts does not.

Changing the use of land into curtilage

Extending a garden into a paddock is a material change of use of land, and therefore development under section 55 of the Town and Country Planning Act 1990. It needs planning permission. It is not something that happens by mowing the grass and moving a fence.

Councils treat these applications on their merits, and the usual objections are landscape impact in open countryside, encroachment into the Green Belt, and the domestication of land that contributes to the rural character of a village edge. In the Green Belt, a garden extension can amount to inappropriate development because of its effect on openness, so do not assume a fence and a lawn will be waved through.

Where permission is granted, the new garden area becomes curtilage, and permitted development rights then apply to it unless a condition removes them. Many councils impose exactly that condition, which is the point at which the applicant realises what they have given away.

Curtilage listing is a separate question

Section 1(5) of the Planning (Listed Buildings and Conservation Areas) Act 1990 treats a structure within the curtilage of a listed building, forming part of the land since before 1 July 1948, as part of the listed building. That protection bites on stables, coach houses, walls, privies and garden structures around listed houses.

The curtilage tested for that purpose is the curtilage at the date of listing, which can be considerably wider than today's garden after a site has been subdivided. Buying a converted coach house that was sold off from a listed hall in the 1970s can mean owning a listed building without a separate entry in the national list.

The tests overlap but are not the same exercise, and an assumption carried across from one to the other causes expensive mistakes. Where a listed building is anywhere nearby, get the position checked before works start.

Evidence that establishes the extent

Assemble the record before you need it.

1. Historic Ordnance Survey extracts showing boundaries and buildings over time, which demonstrate how long the present layout has existed.
2. Aerial imagery at several dates, showing surface treatment and management.
3. The conveyance and title plans, noting that these show ownership rather than curtilage.
4. Dated photographs of fences, gates, hedges and access points.
5. A statement from someone with long knowledge of the property describing how each part has been used.

That package supports an application for a certificate of lawfulness under section 191 or section 192, which is the only formal way to confirm that works are lawful. A Planning Statement can set out the argument, but the certificate is what a future buyer's solicitor will ask for.

What getting it wrong costs

An outbuilding built outside the curtilage is unauthorised development. The council can serve an enforcement notice requiring its removal, and time limits for enforcement have been extended by the Levelling-up and Regeneration Act 2023, with commencement provisions to check at the time.

More often the damage surfaces at sale. A buyer's solicitor asks for evidence that the annexe, garage or home office was permitted development, the seller cannot produce it, and either the sale stalls or an indemnity policy is bought that a lender may not accept. Applying for a certificate before marketing is cheaper than resolving it in a chain.

The related question of principal elevations and how Class A is applied to complicated house shapes is dealt with in the article on curtilage and principal elevation in Class A cases, and the prior approval procedures that sit alongside these rights are covered in how the prior approval procedure actually works.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. Enter your postcode on PlanScope to see which documents an application is likely to need.