Rear Extension Drawings in Westminster
Fixed-fee, MCIAT-chartered rear extension drawings for Westminster homeowners — Westminster City Council validation and local constraints handled from the start.
Westminster is among the most heritage-dense authorities in the country: the great majority of its housing sits within a conservation area — Belgravia, Mayfair, Pimlico, Bayswater, Maida Vale and St John's Wood among them — listed buildings are commonplace, and much of the residential stock is mansion-block or garden-square terrace where external alterations are tightly controlled. The character runs from stucco-fronted Georgian and Victorian townhouses and garden-square terraces to red-brick and Portland-stone mansion blocks across the West End and Marylebone. Permitted development rarely applies, and applications turn on careful, context-led drawings and, frequently, listed-building consent.
Because so much of the city lies within a conservation area and a high proportion of buildings are listed, a full planning application — and often listed-building consent — is usually required even for modest works in Belgravia, Mayfair, Pimlico or Bayswater. The City Plan basement policy requires a basement impact assessment and limits the scale of any below-ground extension, and mansion-block and estate-management leases frequently require the freeholder's consent alongside planning, since either the council or the freeholder can block an otherwise sound proposal. We take a validation-first approach, resolving the conservation, listing, basement and lease position for your exact address before a line is drawn.
We prepare Westminster planning and listed-building submissions to the council's exacting validation and design standards, producing the same council-accepted drawings an architect would — usually at around 30% less. The fee is fixed and agreed up front, drawings typically turn around in about seven days, and we redraw free until the council approves. Most householder applications are determined within the statutory eight-week period once validated, though listed-building, basement and conservation cases frequently attract additional consultation, so a complete, correctly scaled submission that answers the heritage questions early is the best way to keep the application moving.
Planning in Westminster: what to know before you apply
Because the great majority of Westminster falls within a conservation area — and a high proportion of buildings are listed — a full planning application, and often listed-building consent, is usually required even for modest works. The City Plan basement policy requires a basement impact assessment and limits scale, and mansion-block leases frequently require the freeholder's consent alongside planning. We resolve these before drawing.
Typical Westminster housing stock
Stucco-fronted Georgian and Victorian townhouses, garden-square terraces, red-brick and Portland-stone mansion blocks, and a very high concentration of listed buildings across the West End and the garden squares.
Areas we regularly draw for in Westminster
Belgravia · Mayfair · Pimlico · Marylebone · Bayswater · Maida Vale · St John's Wood · Westminster
Rear Extension Drawings for Westminster homes: the package and the process
Every rear extension drawings we prepare for a Westminster property is drawn to Westminster City Council’s validation standards and tuned to the local constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.
A single-storey rear extension is the most common way London homeowners add space, usually taking the form of an open-plan kitchen-diner that opens onto the garden through bi-fold or sliding doors, with rooflights or a roof lantern bringing daylight deep into the plan. Because depth and height are tightly controlled by permitted development rules and by the 45-degree rule that protects neighbouring windows, the design work sits as much in checking what the council will allow as in drawing what you want.
DrawingsDirect draws rear extensions for permitted development, the larger home extension prior-approval scheme and full householder planning, with structural calculations for the opening and roof produced in-house by our MCIAT-chartered team. If your project also involves widening the kitchen sideways or adding a second storey, see our Side Return, Wraparound and Double Storey Extension pages — many London rear extensions grow into one of those during design.
Do I need planning permission for a rear extension in London?
Many single-storey rear extensions qualify as permitted development, meaning no planning application is needed, provided depth, height and materials stay within set limits. That changes if your property sits in a conservation area or is subject to an Article 4 direction, both of which can remove permitted development rights across a street or borough — in that case a full householder planning application is required regardless of size.
Even where an extension qualifies, most homeowners obtain a Lawful Development Certificate to confirm that status in writing before building — useful for mortgage lenders, buyers and Building Control. We check your property against your borough's constraints before recommending a route.
How deep can a single-storey rear extension go?
Depth is the main constraint on a rear extension, and it depends on your house type and whether you use standard permitted development or the larger home extension scheme.
Permitted development
Standard permitted development allows a single-storey rear extension up to 3 metres deep for terraced and semi-detached houses, or 4 metres for detached houses, generally with eaves height limited to match or stay close to the existing house.
Larger home extension scheme
The prior-approval scheme extends this to 6 metres for terraced and semi-detached houses and 8 metres for detached houses. Your council writes to affected neighbours; if none object within the notification period, approval follows without a full planning application. If an objection is raised, the council assesses the impact on neighbouring light and outlook itself, rather than automatically refusing, so a well-considered design still has a good chance of approval.
| Route | When it applies | Typical fee |
|---|---|---|
| Permitted development (Lawful Development Certificate) | Depth within 3m (terraced/semi) or 4m (detached), height and materials within PD limits | PD/LDC pack ~£950–£1,450 |
| Larger home extension (prior approval) | Depth up to 6m (terraced/semi) or 8m (detached), with neighbour notification | from £1,100 |
| Full householder planning permission | Extension exceeds PD/larger-home limits, or the property is in a conservation area with an Article 4 direction | Full Planning pack ~£1,600–£2,400 |
| Planning + Building Regulations (structural) | Combined planning and construction-ready pack with structural calculations for the opening and roof | Planning + Building Regs pack ~£2,200–£3,850 |
Rear Extension Drawings across Westminster
Rear Extension Drawings in Westminster — FAQs
How much does a rear extension cost to design in London?+
Do I need an architect for a rear extension?+
How long does it take to get rear extension drawings?+
What is the 45-degree rule?+
Will I need a Party Wall Agreement for a rear extension?+
Do I need planning permission for works in Westminster?+
I live in a mansion block — what extra consent might I need?+
Will I need a Basement Impact Assessment in Westminster?+
How long does Westminster City Council take to decide?+
How much do planning drawings cost in Westminster?+
Get your free Westminster planning assessment
Tell us your Westminster address and ambition — we'll confirm feasibility, local constraints and a fixed fee within one working day.