One brick back, one metre clear
Stratford-on-Avon District Council's householder note, Extending Your Home, dates from April 2008 and is still on its design guidance page. It is short and specific. A side extension should sit at least 225mm (one brick length) behind the front wall of the house, and its roof should be lower than the main roof. If the side addition goes up to a first floor, the note wants at least a metre kept clear to the boundary.
That metre matters most on the roads radiating out of town. The 2005 studies of Alcester Road, Shipston Road and Evesham Road all use the same blunt phrase: 'terracisation' should be strongly discouraged. On parts of Alcester Road and Evesham Road they add that side extensions should not close the glimpses through to the back gardens. A two-storey side addition tight to the fence is the plan most likely to be refused. There is one let-out. Building up to the boundary at first floor can be acceptable where the neighbour has nothing over one storey within two metres of it.
Going backwards, the guidance sets no maximum depth. Rear additions that pass the light and privacy tests will normally be accepted, and on the long plots west of Shipston Road the study sees room for extending into the gardens.
Light and privacy, measured
The numbers officers check against now sit in the Development Requirements SPD, Part F, adopted in April 2019. Take the nearest ground-floor habitable room window next door and draw a 45 degree line from its middle. If the extension crosses it, a second check at 25 degrees above the horizontal follows. Fail both and the neighbour will normally be judged to lose too much light.
Privacy distances only bite above a single storey. For two storeys the table asks for 21 metres between facing back windows and 10 metres from a window to the neighbour's garden near their house, unless it is obscure glazed. Frosted film on clear glass won't usually do. If your floor sits higher than next door, add two metres per metre of difference.
Choosing the right addition
Single-storey rear. The obvious first move on an inter-war semi off Alcester Road or a post-war house near Clopton Road. Outside the town centre and Shottery conservation areas, 3 metres on a semi or 4 on a detached house goes ahead without an application.
Kitchen. On a semi the neighbour's kitchen or dining room window is usually close to the party wall, so run the 45 degree line before you fix the depth. A lean-to roof dropping towards the boundary can clear the 25 degree check where a taller flat roof fails.
Two-storey. Possible, but the metre gap and the 21 metre distance both apply. On a short garden that can rule out first-floor back windows.
Wrap-around. The side leg is judged as a side extension, so keep it single storey and set back. Inside a conservation area any side element means a planning application.
Side return. Terraces are under a fifth of the district's homes, so this is a job for the older streets nearer the centre. Filling the passage counts as a side extension, which needs an application if you're inside the town centre conservation area.
Open plan. Opening the old back wall needs an engineer's beam. In an old-town timber-framed house that wall may be part of the frame, and if listed the opening needs consent.
Ground-floor bedroom. A real option in a district where the median age is 48. The post-war bungalows on the Evesham Road side sit on wide plots, and a single-storey wing keeps clear of the privacy distances.
Home office. An attached room shares the heating and broadband. On the neo-Tudor houses of Hathaway Lane and Shottery Road, design it to match the house.
Planning. Start by finding out if the house is listed or in a conservation area, then ask the council whether an Article 4 direction or an old estate condition has removed your permitted development rights.
Cost. There's no Stratford figure here. Flood-resistant floors and listed building drawings both shift the price, and three quotes will show how far.
Near the river, and under the trees
The district's 2022 flood risk study puts the low-lying town centre and houses close to the Avon and Shottery Brook at most risk, and part of the west side of Shipston Road is prone to flooding. If your house is in Flood Zone 2 or 3, the application needs a flood risk assessment. Environment Agency standing advice covers householder extensions up to 250 square metres and recommends floors 600mm above the estimated flood level, or flood resistant materials to that height.
Much of the valley floor is river terrace sand, gravel and mud, laid down by the Avon, and it varies from plot to plot. Dig trial holes before the engineer settles the footing.
In a conservation area, cutting back or felling a tree with a stem 75mm or more across at 1.5 metres needs six weeks' notice to the council, and a tree with a preservation order needs consent. Keep skips and stacked blocks off the root area. Stored materials can seriously damage a tree.
Where these facts come from
- Stratford-on-Avon District Council: Extending Your Home (April 2008)
- Development Requirements SPD Part F: Residential Amenity (2019)
- Stratford-on-Avon District Council: residential design guidance
- Alcester Road character study
- Shipston Road character study
- Evesham Road (inc. Shottery) character study
- Permitted development rights for householders, technical guidance (GOV.UK)
- Flood risk assessment: standing advice (GOV.UK)
- Stratford-on-Avon Level 1 Strategic Flood Risk Assessment (2022)
- Stratford-on-Avon District Council: trees in conservation areas
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Questions people in Stratford-upon-Avon ask
We're on Shipston Road with a long back garden. Can we build out a long way?
Quite possibly. There's no maximum rear depth, and the study of the west side sees room for extending along the longer plots. Part of that side is in a conservation area and parts flood, so check both first.
Next door has a two-storey side extension right up to our fence. Does that stop us doing the same?
It changes the answer. The 2008 note wants a one metre gap at first floor to stop houses joining into a terrace, but it can accept building to the boundary where the neighbour has nothing over one storey within two metres. If they already do, expect to keep the gap or stay single storey.
Our house in Shottery is neo-Tudor. Will a standard conservatory be a problem?
Yes, Shottery is covered by the Evesham Road study. It says standard attached conservatories are likely to look out of place on those houses and that extensions should reflect the neo-Tudor style. A designed garden room will have a better chance.
Is there a percentage limit on extensions in Stratford?
No percentage applies to an ordinary house in the town. Each scheme is judged on design, light and privacy. Permitted development has its own limits, and the Green Belt has separate rules, so if you're on the rural edge ask the planners which apply.