Measured from next door's back wall
Two sets of numbers apply to a Rochdale extension, and they are measured from different places. Permitted development, the national allowance, lets a single storey addition go 3 metres beyond the original back wall of your own house if it's attached, or 4 metres if it's detached, with a 4 metre height cap. Stay inside that and no application is needed.
Once you do need permission, the council reads the drawings against its Guidelines and Standards for Residential Development. Adopted in 2016, it turns up in every householder report the planners write. Paragraph 5.6 uses a point 3 metres along the shared boundary for attached houses and 4 metres for detached, measured from the neighbour's rear wall rather than yours. On a terrace where next door already built out, that can work in your favour. Officers have accepted deeper single storey projections where the neighbouring extension or outhouse already reaches further along the boundary.
Upstairs is tighter. A two storey or first floor rear addition shouldn't cross a 30 degree line drawn from a point 2.4 metres along the common boundary. On a narrow mill terrace that rarely leaves much, which is why most two storey jobs here end up on semis and detached houses.
Single storey rear. The default in Rochdale's stone and brick terraces, and usually the one job that fits permitted development. Check whether an old back kitchen already counts as an extension before you measure the 3 metres.
Kitchen. Terrace kitchens here tend to be dark rooms at the back of a deep plan. Roof glazing over the new part often does more than the extra floor, so spend the money there.
Open plan. Opening a back room into the extension means taking out a wall that may carry stone above it. Get the steel sized by an engineer before any builder fixes a price.
Two storey. Mostly a semi job, on the interwar and postwar estates. The council's guide wants the side version kept from joining neighbouring pairs into a terrace, so expect talk of a set-back at the front.
Wrap-around. Works on the bigger semis and detached houses. The side leg takes it out of permitted development in any conservation area, and on a corner plot the council looks hard at the building line.
Side return. Only where the back offshoot leaves a strip beside it. Plenty of terraces here have one, but walls on both sides can mean a party wall notice to each neighbour.
Ground floor bedroom. Rochdale's terrace stairs are steep and narrow. A bedroom and level shower room at the back can keep someone in the house they know, as long as the garden left behind still passes the council's test.
Home office. Small terrace gardens don't leave space for a cabin, so an attached room is often the realistic choice. Under permitted development, extensions and outbuildings together can't cover more than half the land around the house.
Planning. Rochdale has 28 conservation areas, and inside them side additions and anything over one storey at the back need an application. Around Prickshaw, Croft Head and Broadley Fold even a single storey rear addition does.
Cost. No Rochdale figure from us. Stone walls, footings over old coal workings and drainage under a back street change the bill too much from house to house.
Pennine farmhouses and the 35 per cent guide
Plenty of Rochdale's older farmhouses and folds sit outside the town in the Green Belt, and that is where people tend to want the biggest additions. National policy only allows extensions there that aren't disproportionate. Rochdale puts a number on it. Paragraph 5.20 of the council's guide treats up to a 35 per cent increase in floor space or volume over the original house as normally acceptable.
Original means as first built, or as it stood on 1 July 1948. Every extension since then counts, including ones a previous owner added. The guide does say houses vary, so 35 per cent can be too much on one plot and more can pass on another, but go in expecting that figure to be the starting point.
Prickshaw, Croft Head and Broadley Fold have their own rule. A 1989 Article 4 direction there removes the permitted development rights for extensions, porches and boundary walls, so every addition needs planning permission.
The Roch, the Coal Measures and digging footings
The River Roch runs through Littleborough and the town, and the Boxing Day floods of 2015 led to the Environment Agency's scheme between Smithy Bridge and the centre. If your house is in Flood Zone 2 or 3, an extension application needs a flood risk assessment. The Agency's standing advice is to set new floors at least 600mm above the expected flood level, or build in flood resistance where you can't.
Under most of the built-up area lie Coal Measures, with old shallow workings recorded by geologists and landslips in the steep valleys. Look the address up on the Mining Remediation Authority's map before foundations are designed. In a development high risk area its guidance says you need its permit before work that could disturb seams or old workings, and you should keep clear of mine entries.
Where these facts come from
- GOV.UK: permitted development rights for householders, technical guidance
- Rochdale Borough Council: officer report applying SPD para 5.6
- Rochdale Borough Council: officer report applying SPD para 5.9
- Rochdale Borough Council: officer report applying SPD para 5.20 (Green Belt)
- Rochdale Cabinet report on the residential development SPD
- Planning Data: Rochdale Article 4 directions
- Environment Agency: flood risk assessment standing advice
- Environment Agency: Rochdale and Littleborough flood scheme
- Mining Remediation Authority: home extensions in former coal mining areas
- British Geological Survey: geology of the Rochdale district
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Questions people in Rochdale ask
Next door built a long kitchen years ago. Does that help my application?
It can. The council's guide measures a single storey rear projection along the shared boundary from the neighbour's back wall, and officers have approved deeper extensions where the neighbouring one already reaches further.
Can I put a two storey extension on the back of my terrace?
Permitted development allows one only within 3 metres of the original rear wall and at least 7 metres from the back boundary, which few Rochdale terraces have. With an application, the council checks it against a 30 degree line from 2.4 metres along the boundary, so a narrow house often gets very little.
Our house is in the Green Belt. How much can I add?
Start from the council's guide of about 35 per cent over the house as first built or as it was in 1948, counting earlier extensions. It's a guide, not a fixed cap.
We live by the Roch. Will flooding stop us extending?
Not on its own. In Flood Zone 2 or 3 you need a flood risk assessment with the application and a raised floor or flood resistant construction. Check the Environment Agency's flood map first.