Front extensions: what you can actually build
Nearly every front extension in England needs planning permission. Extending forward of the front wall of your house is not permitted development, so you cannot build one without an application — the single exception being a small porch. This page explains why the front is treated differently, and how to get a scheme through.
The short answer
The permitted development rights that let people add rear and side extensions without a planning application stop at the front of the house. Anything that projects beyond the principal elevation — the main face of your home, usually the wall that fronts the road — needs full planning permission. The same goes for a side wall that faces a highway.
So a bay window pushed forward, a hallway widened towards the street, a full single-storey room across the front: all of them are planning applications, not permitted development. The only thing you can add to the front without applying is a porch, and only if it stays inside the limits below.
That does not mean a front extension gets refused. Plenty are approved every year. It means the council gets to decide, and how you design it matters far more than it would at the back.
Why the front is treated differently
Permitted development is deliberately generous at the rear, where an extension mostly affects you and your immediate neighbours. The front is public. It shapes the street, so the planning system keeps control of it. The General Permitted Development Order spells this out: any enlargement in front of the principal elevation, or in front of a side elevation fronting a highway, is excluded from permitted development.
| What you want to add at the front | Permitted development? |
|---|---|
| Single-storey front extension (any size) | No — planning permission required |
| Two-storey or first-floor front extension | No — planning permission required |
| Forward-projecting bay window | No — planning permission required |
| Porch up to 3m² footprint, up to 3m high, 2m+ from any highway boundary | Yes — permitted development under Class D |
Source: Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 1 (Class A exclusions and Class D porches), and the GOV.UK Permitted development rights for householders: technical guidance. Rights are further restricted on designated land and can be removed by an Article 4 direction or a condition on your property.
The porch exception, in full
A porch is the one thing you can build forward of the front wall without asking. Class D allows it, but three limits have to all be met, measured externally:
- ground floor area no greater than 3 square metres;
- no part higher than 3 metres above ground level;
- no part within 2 metres of any boundary of the house with a highway.
That last one catches people out. If your front door sits close to the pavement — common on older terraces — a porch large enough to be useful can breach the 2m rule, and then it needs permission like anything else. Measure the gap before you get drawings done.
Our porch extension rules page goes through the detail, including what happens in conservation areas where these rights are often withdrawn.
What the council looks at
Because a front extension is judged on planning merits rather than a fixed set of measurements, design is everything. The building line along your street is the big one: councils resist anything that breaks the rhythm of front walls, because one house jutting forward tends to invite the next. If every other home on the terrace sits flush, a bold forward projection is a hard sell.
Officers also weigh the effect on the street scene, whether the materials and proportions match the existing house, sight lines for drivers where the extension meets a junction or drive, and the impact on light and outlook for the homes either side. A modest, well-matched addition that respects the building line stands a good chance. A large box that dominates the frontage does not.
A householder application in England is normally decided within 8 weeks. If you build to the edge of what the porch rules allow, it is worth getting a lawful development certificate so you have written proof it did not need permission — useful years later when you sell.
One thing that does not apply here: the neighbour consultation and prior approval routes used for larger rear extensions. Front extensions go straight to a normal planning application.
Building Regulations still apply
Planning permission is only half of it. A front extension has to be built safely, so Building Regulations cover the foundations, structure, insulation, drainage and any change to the front door or electrics. That is separate from planning and applies even to the smallest room.
A porch is the exception again: it is usually exempt from Building Regulations if it sits at ground level, is under 30 square metres, keeps the original front door between it and the house, and its glazing and any electrics meet the rules. Take the front door out to open the porch into the hallway and the exemption falls away.
What a front extension costs
A front extension is priced like any other single-storey addition — the work is the same, it just faces the street. BestBuilders’ 2026 regional cost model (published national cost guides × a regional labour index, averaged across 519 UK towns) puts a standard-specification single-storey extension at roughly £2,200–£3,200 per square metre of floor area, before VAT and fees. A porch sits well below that because it is small and often glazed rather than fully built.
Add the £548 planning fee (see below), plus drawings and, if the structure is complex, a structural engineer. For a full breakdown by size and finish, see BestBuilders’ front porch extension cost guide.
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