St John's Wood · Westminster
House extension architects in St John's Wood
Rear, side-return and wrap-around extensions in St John's Wood (NW8), designed in 3D around how you live and around Westminster Council's planning expectations.
What do I need to know about extensions in St John's Wood?
Many single-storey rear extensions in St John's Wood can be built under permitted development (up to 3m deep for semis/terraces, 4m for detached, or 6m/8m with prior approval), but flats, conservation areas, Article 4 areas, side extensions over half the house width and two-storey schemes need planning permission from Westminster Council.
The rules at a glance
- Single-storey rear: 3m (attached) or 4m (detached) under permitted development
- Larger Home Extension prior approval: up to 6m / 8m
- Side extensions: single storey, no wider than half the original house
- Conservation areas and flats: planning permission usually required
General national guidance; every address is checked individually before design.
Planning in Westminster
Westminster's planners hold a high bar on materials, joinery detail and streetscape continuity, especially around St John's Wood.
Most of Westminster is in conservation areas, so even modest rear and roof alterations usually need full planning consent. We design to the Westminster City Plan and conservation area guidance.
Typical housing we see in St John's Wood:
- Period terraces and semis around St John's Wood centre
- Post-war infill closer to the NW8 boundary
- Larger detached stock on the leafy northern edge
- Mixed-use frontages along the main high street
How we work
We start remotely: a Matterport scan gives an accurate 3D model of your home, we design options you review on video calls, then produce concept drawings. Planning and Building Regulations drawings follow only if your project needs them.
FAQs
Questions
Everything you need to know about working with DOR Architects.
Build costs depend on size, glazing and finishes. Most St John's Wood single-storey extensions we see fall broadly in the £2,500–£3,500 per m² range for build with a mid-range finish, excluding VAT, fees and the kitchen; see our North London extension cost guide for the full breakdown. Our Stages 0–2 (survey, existing drawings and concept design) are offered as a fixed estimated fee; planning drawings (Stage 3) and Building Regulations drawings (Stage 4) are optional add-ons only if you need them.
No architect can guarantee approval. We design to the Westminster City Plan and conservation area guidance and recent local decisions to give your scheme the best chance.
We start remotely: a Matterport scan produces an accurate 3D model of your home, so we can design and review options with you on video calls.