No local rulebook, so the neighbours' windows decide
Plenty of councils publish a householder design guide with a 45-degree line and set distances to the boundary. Peterborough doesn't. Its list of supplementary planning documents covers village design, flood and water, shop fronts, developer contributions and green infrastructure, and nothing on house extensions.
Instead, when a scheme reaches the planning committee, officers weigh it against two policies in the 2019 Local Plan. LP16 asks that new work should "contribute positively to the character and distinctiveness of the area". LP17 says permission will not be granted for development causing "an unacceptable loss of privacy", and goes on to daylight, overbearing impact and noise. There is no number to hide behind. A planner stands in the neighbour's garden and makes a judgement.
We think that suits a well-designed scheme and punishes a lazy one. A tall blank wall on the boundary of a township semi reads as overbearing. Drop the eaves and hip the roof away from next door, and the same depth often goes through.
One more local habit to know about. The council's planning advice page says it "is unable to provide informal written or verbal advice" on whether you need permission. If you want certainty that a job is permitted development, you apply for a lawful development certificate. For anything that needs permission, the council strongly recommends pre-application advice first.
Ten ways to add room, fitted to Peterborough houses
Planning first. Outside a conservation area, the national allowance lets you build 3 metres out from the original back wall (4 if detached) without an application, or up to 6 and 8 metres through the prior approval route, which the council has 42 days to answer. Some of the city's 56 Article 4 directions take extension rights away, so ask the conservation team if your street is an old one.
Single-storey rear. The job most Peterborough families start with, and usually the one with the fewest hurdles. The cap is 4 metres high, and inside 2 metres of a boundary the eaves can't go above 3.
Kitchen. On a Victorian terrace in the railway streets the old kitchen is often dark and at the back of the outrigger. Putting the glass on the garden side, with a rooflight over the sink, does more than another metre of floor would.
Side return. Suits those same terraces, where a narrow yard runs beside the back addition. In the Park, Queens Road or GNR Cottages conservation areas, filling it needs a planning application, even at one storey.
Open plan. Taking out the old back wall means a steel beam and new pads to carry it. On made ground or river alluvium the engineer may want to see a trial hole before sizing those pads.
Wrap-around. The side leg can only be half the width of the original house under permitted development, and none of it is allowed in a conservation area.
Two storey. Permitted development stops at 3 metres deep and needs 7 metres clear to the back boundary, which rules out many compact township and Hampton gardens. Expect an application, and expect LP17's privacy test to be the hard part.
Downstairs bedroom. Often the better answer than a stairlift in a 1970s or 1980s township house with a decent side garden. Plan level thresholds and a wide door from the start.
Home office. Attached rooms share your heating and broadband, which matters if you work at home five days a week. A cabin at the end of a fen-edge garden may also land within 7 metres of a dyke.
Cost. We don't publish prices. The local things that move a quote are foundation depth, drainage consent and whether the council asks for a flood risk assessment. Get three builders to price one set of drawings.
Drains, dykes and soft ground
East of the city the fen is a grid of drains, and some of them run past back gardens. The council's land drainage byelaws say that if your work is within 7 metres of an ordinary watercourse, you may need its consent. Where the drain belongs to an internal drainage board, the board gives consent instead, and for a main river it is the Environment Agency. Ask the council's drainage team before you dig.
Most of Peterborough is in Flood Zone 1. Parts to the north and east are in Zones 2 and 3, and the Environment Agency's Nene flood plan names Woodston, Stanground, Orton Longueville and Fengate among the southern parts at risk from the river. If you are in Zone 2 or 3 and need planning permission, a flood risk assessment goes in with the application. For a householder addition up to 250 square metres, the Environment Agency's standing advice for minor extensions is the route to follow.
The ground itself changes across town. The British Geological Survey's Peterborough memoir describes Oxford Clay under much of the district and flat, poorly drained ground on it near Werrington. Old brick pits have been filled. Near the river, a borehole at the old East Station went through almost five metres of alluvium with thin peat beds in it. So the depth your neighbour dug is no guide to yours.
Stone villages with their own rules
A group of villages, from Barnack and Castor to Thorney and Wansford, is covered by the council's 2011 Design and Development in Selected Villages document. It gives no measurements. It gives clear instructions. In Thorney, extensions "should be subservient and smaller than the principal building", and materials and detailing should match. At Barnack and Pilsgate, materials should match the original. Glinton asks you to think about how the extension looks from footpaths and open space, not just the road.
Most of these villages are also conservation areas, so the national rules close off side extensions, two-storey rear additions and cladding without permission. A single-storey back addition in matching stone is the scheme most likely to sail through.
Where these facts come from
- Peterborough City Council: supplementary planning documents
- Peterborough City Council: planning advice
- Peterborough City Council: Design and Development in Selected Villages SPD (2011)
- Peterborough City Council: works near a watercourse
- Peterborough City Council: Article 4 directions
- Peterborough City Council: conservation areas
- Environment Agency: River Nene Catchment Flood Management Plan
- British Geological Survey: geology of the Peterborough district
- GOV.UK: flood risk assessment standing advice
- GOV.UK: Permitted development rights for householders, technical guidance
How FirQuote works in Peterborough: We connect you with local specialists who visit your property before giving you a price. You get up to 3 written quotes — no call centres, no estimates from photos, no obligation to accept any quote.
Questions people in Peterborough ask
Will the council tell me over the phone whether my extension needs permission?
No. Its planning advice page says it can't give informal written or verbal advice on that. You either check the national rules yourself or apply for a lawful development certificate, which gives you a formal answer.
Our garden backs onto a fen drain. Can we still build?
Usually, yes, but you may need consent first. Under the council's byelaws, work within 7 metres of an ordinary watercourse may need its approval, and if the drain is run by an internal drainage board, apply to the board.
Is there a 45-degree rule in Peterborough?
Not as a written council standard. Officers judge householder schemes on loss of privacy, daylight and overbearing impact under Local Plan policy LP17, so good drawings showing the effect on next door help.
We live in Thorney. Does the village have extra design rules?
Yes. The 2011 village design document says Thorney extensions should be subservient and smaller than the main house, with matching materials and detailing, and rear additions to Bedford Cottages should be secondary in scale.