Outbuildings near a boundary and the 2.5 metre limit
Class E caps outbuilding height at 2.5 metres within two metres of any boundary, measured from the highest adjacent ground. The coverage test, the front garden exclusion and the raised platform rule.
The outbuilding height boundary limit is the rule that catches more householders than any other part of Class E. Within two metres of any boundary of the curtilage, an outbuilding may not exceed 2.5 metres in overall height. Move it further than two metres from every boundary and the limit rises to 3 metres for most roof forms, or 4 metres where the roof is dual-pitched. The limit is measured to the highest part of the structure, not to the eaves, and the ground it is measured from is the highest part of the surface next to the building. Those three details decide most garden room disputes.
The height limit within two metres of a boundary
Class E of Part 1 of Schedule 2 to the General Permitted Development Order 2015 permits buildings and enclosures within the curtilage of a house for a purpose incidental to its enjoyment. The height limits are:
- 4 metres, where the building has a dual-pitched roof and sits more than two metres from every boundary.
- 3 metres in any other case, where the building sits more than two metres from every boundary.
- 2.5 metres, where any part of the building is within two metres of a boundary of the curtilage.
- 2.5 metres for the eaves height, in every case.
The two metre test is about distance from the boundary of the curtilage, not from the neighbour's building, and not from the fence if the fence is not on the boundary line. If the boundary runs along the centre of a shared hedge, measure to the centre of the hedge.
A garden room with a flat roof, a 2.4 metre internal ceiling and a 150 millimetre roof build-up will exceed 2.5 metres overall once the floor slab is added. That is the single most common breach, and the fix is usually to dig the floor down rather than to move the building.
Measuring from the adjacent ground level
Height is measured from ground level, and ground level for this purpose is the highest part of the surface of the ground next to the building.
On a sloping garden that works against you. Build into a slope and the measurement is taken from the high side, so the building looks 2.4 metres tall from the patio and measures 2.9 metres from the point that counts.
Two practical responses. Survey the levels before designing, with spot levels at each corner of the proposed building and at the boundary. And where the slope is awkward, step the slab or lower the floor rather than arguing about where the ground is, because the officer will measure from the high point.
Decking and raised slabs make this worse, because they raise the adjacent ground. A building set on a raised platform starts its height measurement from the platform surface if that is now the highest adjacent ground.
The fifty per cent curtilage coverage test
The second limb of Class E caps how much of the garden can be built on. The total area of ground covered by buildings, enclosures, pools and containers within the curtilage, other than the original dwelling house, must not exceed 50 per cent of the total area of the curtilage excluding the ground area of the original dwelling house.
Two words do the work. Original means the house as it stood on 1 July 1948, or as first built if later, so a large rear extension built in 2005 counts against the 50 per cent, not as part of the house.
And everything counts. Sheds, the greenhouse, the bin store, the oil tank, the pool, the summer house built by the previous owner, and in most readings a substantial decked enclosure. Add them up before adding another.
Measure the curtilage properly too. It is the land attached to and serving the house, which on a long plot with a paddock at the end may be less than the registered title.
Front gardens and why Class E excludes them
Class E does not permit any part of the building forward of a wall forming the principal elevation of the original house.
That is a hard line and not a matter of degree. A bin store, a bike shed or a log store in the front garden needs planning permission, however modest it is, if any part of it sits forward of that wall. On a house set at an angle to the road, work out which elevation is the principal one before assuming, because it is the elevation that fronts the main access rather than necessarily the one facing the street.
The same logic makes front garden work harder generally, which is covered in why front extensions are harder than rear ones.
Verandas, balconies and raised platforms
Class E does not permit the construction or provision of a veranda, balcony or raised platform. A raised platform means one more than 300 millimetres above the ground.
So a garden room is fine. A garden room with a decked terrace 400 millimetres above the lawn in front of it is not, and the deck needs permission even though the building does not. Low-level decking under 300 millimetres is outside the restriction.
This matters more than it sounds, because a raised deck at the end of a garden produces exactly the overlooking that neighbours object to. The same issue arises with terraces formed on extension roofs, dealt with in Juliet balconies, terraces and overlooking from an extension.
Designated land and listed buildings
On article 2(3) land, which covers conservation areas, National Parks, the Broads, National Landscapes and World Heritage Sites, Class E is not permitted where the building would be situated on land between a side elevation of the house and the boundary of the curtilage. Side returns are therefore out.
In National Parks, the Broads, National Landscapes and World Heritage Sites there is a further limit: the total area of ground covered by buildings more than 20 metres from any wall of the house must not exceed 10 square metres. A shed at the bottom of a long garden is caught by this even though it is invisible from anywhere.
Class E is not available at all within the curtilage of a listed building. Curtilage listing extends to structures that formed part of the land with the listed building before 1 July 1948, so an old coach house or garden wall may be listed without being separately described. Where a listed building is in the picture, the works need listed building consent and a heritage statement to support it.
Article 4 directions can withdraw Class E entirely in a defined area, which many conservation areas have done. Check before you build.
Recording the measurements before you start
Keep evidence, because permitted development rights are proved by the person relying on them.
Before construction, record the existing levels with a dated level survey, photograph the boundary positions, and calculate the curtilage coverage with the arithmetic written out and every existing structure listed. After construction, photograph the finished building with a staff or tape visible against the highest adjacent ground.
A lawful development certificate under section 192 of the Town and Country Planning Act 1990 is the only formal way to confirm that the works are lawful, and it is worth the fee where the building is close to a limit or where you may sell within a few years. A buyer's solicitor will ask, and a certificate answers the question in a way that photographs do not.
Enter your postcode on PlanScope to see which documents a householder application would need if your outbuilding falls outside Class E.
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.
Frequently asked questions
How tall can a shed be near a fence?
Where any part of the building sits within two metres of a boundary of the curtilage, the maximum overall height under Class E is 2.5 metres. Further than two metres from every boundary, the limit is 3 metres, or 4 metres for a dual-pitched roof. The eaves height limit of 2.5 metres applies in every case.
Where is the height measured from?
From ground level, which for this purpose is the highest part of the surface of the ground next to the building. On a sloping garden that means the measurement is taken from the high side, so a building that reads as 2.4 metres from the patio can measure well over the limit from the point that counts. Survey spot levels before designing.
What is the 50 per cent curtilage rule?
The total ground area covered by buildings, enclosures, pools and containers within the curtilage, other than the original house, must not exceed half the curtilage area excluding the original house footprint. Original means the house as at 1 July 1948 or as first built if later, so later extensions count towards the 50 per cent.
Can I build a shed in my front garden?
Not under Class E. The class does not permit any part of a building forward of a wall forming the principal elevation of the original house, so a front garden bin store, bike shed or log store needs planning permission however small it is. On a house set at an angle, identify which elevation is the principal one before assuming.
Does decking need planning permission?
Class E does not permit a veranda, balcony or raised platform, and a raised platform means one more than 300 millimetres above the ground. Decking below that height is outside the restriction. A raised terrace alongside a garden room therefore needs permission even where the building itself does not, which is where overlooking objections usually arise.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.