The 45 degree line and your neighbour's window
If your plans go to Burnley Borough Council, the first thing a planning officer will draw is a line. The council's Residential Extensions SPD takes it from the middle of the nearest main window to a neighbour's habitable room, at 45 degrees, across the plan and the elevation. Your extension shouldn't cross it. The guidance applies that splay up to 12 metres from the window, which on a row of houses with back yards covers almost everything you might build.
The same document sets 20 metres between facing windows of habitable rooms and 15 metres where a window looks onto a blank gable. Add 3 metres for each storey above two. They matter most once you go up a floor.
Plenty of jobs never reach a planning officer. Under the national permitted development rules a terraced or semi-detached house can go 3 metres out from its original back wall, a detached one 4 metres, with a height of no more than 4 metres and eaves of 3 metres if you're within 2 metres of the boundary. Prior approval lets you go to 6 or 8 metres once the neighbours have been consulted. An old back kitchen added after 1948 counts against that allowance.
Which types work on Burnley houses
Single storey rear. Most local jobs are this one. The SPD accepts a flat or mono-pitch roof if it's well designed, and wants the ridge kept just below the sill of the bedroom window above.
Kitchen. The back of a stone terrace is usually its darkest room. A rooflight over the sink does more than an extra metre of floor.
Open plan. Removing the back wall of a Victorian stone house is structural work. Get the steel sized before you fix a layout.
Side return. Only where the back kitchen leaves a strip of yard alongside it. The council asks that extensions don't cut off rear access, so leave a route for the bins to reach the back street.
Two storey. The SPD says two storey rear additions are often unsuitable on terraces and semis, and flat roofed ones won't normally be supported. At the side, the upper floor should step back at least 1 metre from the front wall.
Wrap-around. One for the semis and detached houses with room at the side. The side leg takes it outside permitted development, so plan on an application, and on keeping the gap to next door open.
Ground floor bedroom. Narrow terrace stairs get harder with age. A bedroom and level shower room at the back can keep someone at home if door widths are settled at drawing stage.
Home office. Few Burnley yards have space for a cabin as well as the bins. An attached room off the kitchen is warmer and easier to wire.
Planning. In the ten conservation areas, from Harle Syke to Padiham, side extensions, cladding and anything over one storey at the back all need permission. Elsewhere a lawful development certificate is cheap insurance.
Cost. We don't print a Burnley figure. Stone walling and what turns up under the footings vary too much. Get three builders to price the same drawings.
The Calder, the Brun and Green Brook
Water is the next thing to check. The council's Local Plan names the River Calder and its tributaries as the main river risk, with the Brun through Burnley and Pendle Water and Green Brook at Padiham. Large parts of the town centre and of Burnley Wood and Fulledge lie in Flood Zone 3, and Padiham town centre flooded badly in December 2015.
If your house is in Flood Zone 2 or 3 and you apply for planning permission, you'll need a flood risk assessment with it. For a householder extension the Environment Agency's standing advice covers it. Floor levels should sit at least 600mm above the estimated flood level, or 300mm where that level is known with real certainty. If you can't raise the floor, build in flood resistant materials and fittings to that height instead.
Check for culverts too. Council guidance says no development should go within 8 metres of the top of the bank of a watercourse, open or culverted, unless the Environment Agency or the flood authority agrees. You may need a separate flood risk activity permit.
Shafts under the older streets
Burnley was a mining town as well as a weaving one. A study of the coalfield by the Northern Mine Research Society found the shallowest coal under the town centre and older Victorian areas, with shafts that can't always be located. An extension needs new footings, so this matters more than it does for a loft.
Householder applications don't need the Coal Authority's mining risk report. Government guidance for old coalfields still says to check the risk if you're in a development high risk area and to avoid building over or near a mine entry. Work that could disturb old seams needs a permit. If the digger finds something odd, stop and ring the Mining Remediation Authority's 24 hour hazard line.
Out of town the Green Belt covers much of the north and west of the borough. There the council says an extension mustn't be a disproportionate addition over the original building. It gives no percentage, so talk to the planners early.
Where these facts come from
- Burnley Residential Extensions SPD (adoption draft)
- GOV.UK: Permitted development rights for householders, technical guidance
- Burnley Local Plan: spatial portrait
- Environment Agency: flood risk assessment standing advice
- Mining Remediation Authority: home extensions in former coal mining areas
- Coal Authority: planning applications and coal mining risk assessments
- Northern Mine Research Society: The Burnley Coalfield
- Burnley Borough Council: conservation areas
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Questions people in Burnley ask
My terrace backs onto a shared back street. Can an extension fill the whole yard?
Rarely. Permitted development caps a single storey rear extension at 3 metres from the original back wall on a terrace, and the council's guidance says extensions shouldn't sever rear access. Keep a way through for the bins.
Will the planners accept a flat roof on my kitchen extension?
Usually, on a single storey job at the back. Burnley's SPD says a flat or mono-pitch roof of reasonable design may be acceptable there. On a two storey extension, or a side one visible from the street, expect them to want a pitched roof that matches the house.
I live near the Calder in Padiham. Does that stop me extending?
No, but if you need planning permission and you're in Flood Zone 2 or 3, the application needs a flood risk assessment. Your designer should set the floor at least 600mm above the estimated flood level, or use flood resistant construction.
Does a stone house need a stone extension?
National rules ask for materials of similar appearance, and the council wants slates and tiles matched for colour, size and texture. On a sandstone terrace in a conservation area, plan on stone. Elsewhere a close match is still expected, and your builder should show you samples.