Measured from next door's back wall
Blackpool has never written its own householder guide. It shares one with Fylde and Wyre, called Extending Your Home, adopted in November 2007 and still on the council's list of planning documents. When you apply, that is the book the case officer opens.
For a single storey at the back, it says the new room shouldn't stick out more than 3 metres past the main rear wall of the house next door. Sit it half a metre in and you can go to 3.5 metres. Upstairs is far tighter. A first floor on the boundary is held to 1.5 metres, and moving it in only earns half the gap, so half a metre in gives you 1.75.
Note what the measurement runs from. It's the neighbour's wall, not yours. If next door already has a deep kitchen out the back, your allowance grows with it. If their house sits further forward than yours, it shrinks.
Side additions have their own figures. Single or two storey, the guide wants a gap of at least 1 metre to the side boundary and the front wall set back by at least 1 metre. Go up two floors and the ridge has to sit at least half a metre under the main roof. The point is to stop pairs of semis joining up into what the guide calls a terraced effect. Upstairs windows also need 21 metres to any facing habitable room window.
Choosing the right build for your street
The council describes the resort and inner neighbourhoods as intensively built, and it won't accept a rear addition that leaves too little garden. On a tight back yard that rule often matters more than any depth figure.
Single storey rear. Outside a conservation area, 3 metres on a terrace or semi (4 detached) goes up without an application. The national 6 metre prior approval route is there too, but plan to the 3 metre line if you think you'll ever apply for anything else.
Kitchen. Behind a Layton or Raikes terrace the back room gets little daylight once you build out. Rooflights over the join do more for the kitchen than an extra half metre of floor.
Side return. Where an older terrace has a back offshoot, the yard strip beside it is the space to fill. Because the guide measures from next door's wall, check how far their own offshoot runs first.
Open plan. Knocking the back wall through means a steel, and building control want to see it before it is boxed in. Size the beam before fixing the layout.
Wrap-around. Mostly a semi or detached job, such as the big houses round Stanley Park. The side leg needs its 1 metre gap and set-back if you apply. Without an application the side leg is capped at half the house's width, and in Stanley Park it isn't allowed at all.
Two storey. Hard on a terrace, because the 1.5 metre first-floor limit leaves you very little. More realistic to the side of a semi, kept a metre off the boundary with the roof stepped down.
Ground floor bedroom. Layton and Marton Moss both have their share of bungalows, and a bedroom with a level shower on the back of one is often a better answer than a stairlift. On Marton Moss, check the flood zone before choosing the floor level.
Home office. With small Blackpool gardens, an attached study usually beats a cabin at the bottom of the yard.
Planning. Most of the borough has normal householder rights. Raikes Hall and Stanley Park don't, and flats have none at all.
Cost. We don't publish figures for Blackpool. Ground conditions, a steel and whether you need drawings for the council all move the price, so get three quotes against the same plans.
Where an application is always needed
In any of the seven conservation areas, national rules take away three things. No side additions, nothing at the back over one storey, and no cladding in render, pebble-dash, timber or tile. The 6 metre prior approval route is gone too, so a single storey rear stops at 3 metres (4 for detached) before you need to apply.
Two areas go further. The Raikes Hall Article 4 direction, in force since 1 June 2020, covers the enlargement of a house under Class A, with no exception for the back. So even a small rear room there needs permission. Round Stanley Park the direction has been in place since 1984, and the council's letter to homeowners lists enlargement among the things that need consent.
Flats are the other big group. Blackpool has nearly double the national share, many of them old holiday premises, and permitted development for extensions doesn't apply to a flat. Inside the inner areas the council's conversion guidance also rules out extending a building as part of turning it into flats.
Low ground at Marton Moss and Anchorsholme
The council's flood study says the sea defences keep coastal flooding limited. The exception is a pocket of Marton Moss bounded by Progress Way, School Road and Midgeland Road, now in Zones 2 and 3 because the surface water depends on pumping stations. An extension there needs a flood risk assessment with the application. Environment Agency standing advice asks for floor levels at least 600mm above the estimated flood level, or flood resistant construction to that height.
Anchorsholme is the other place to ask questions, after a sea incursion in 1977 and sewer flooding in 2000 and 2002 and more flooding there in 2017. As for the ground, the British Geological Survey records wind-blown sand round Blackpool, tidal clays and silts, and buried peat layers in places. Have your engineer dig a trial hole before the foundation is designed.
Where these facts come from
- Blackpool, Fylde and Wyre: Extending Your Home SPD (2007)
- Blackpool Council: supplementary planning documents
- Blackpool Council: Raikes Hall Article 4 direction
- Blackpool Council: Stanley Park Article 4 direction
- Blackpool Council: conservation areas
- Blackpool Council: Strategic Flood Risk Assessment update (2020/21)
- Environment Agency: flood risk assessment standing advice
- GOV.UK: permitted development technical guidance
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Questions people in Blackpool ask
We used to run the house as a B&B and it has a sun lounge on the front. Can we enlarge it?
Front additions need planning permission, and the shared design guide only accepts them when they are modest and sit comfortably in the street. The guide notes that holiday streets often have single storey sun lounges at the front, so matching the neighbours helps.
Next door built out 4 metres a few years ago. Can I go further than 3?
Under the council's guide, yes. Its 3 metre limit runs from the main rear wall of the neighbouring house, so their extension is part of the picture. Without an application you're still held to the national 3 metres from your own wall.
I'm in Raikes Hall. Is a small single storey at the back still permitted development?
No. Since June 2020 the Article 4 direction has covered Class A enlargements, so a planning application is needed for any extension, however small.
Can I put a two-storey side extension on my semi?
Usually, with an application. Keep it at least a metre from the boundary, set the front back by a metre and drop the ridge at least half a metre under the main roof, which is what the council's guidance asks for.