
Basement Conversion Drawings in Northolt UB5
Fixed-fee, MCIAT-chartered basement conversion drawings for Northolt (UB5) homeowners — London Borough of Ealing validation and local constraints handled from the start.
In Northolt (UB5) we prepare planning and building-control drawings for rear extensions, loft conversions and garage conversions on the district's 1930s semis and interwar homes.
Around the Northolt Village Green conservation area we check the boundary and the setting of nearby heritage buildings first, then advise whether your extension runs as permitted development or needs a full application.


Planning in Northolt (UB5): what to know before you apply
The bulk of 1930s UB5 housing sits outside the small Village Green conservation area and keeps full permitted-development rights for rear extensions and lofts. Plots near the green face conservation-area control on demolition, side extensions and anything affecting the historic setting.
Typical Northolt housing stock
Northolt centres on the historic Village Green around St Mary's Church and Court Farm Road, but the wider UB5 district is predominantly 1930s semi-detached and interwar suburban housing with good-sized rear gardens.
Streets we regularly draw for in Northolt
Ealing Road · Court Farm Road · Church Road · Islip Manor Road
Basement Conversion Drawings for Northolt (UB5) homes: the package and the process
Every basement conversion drawings we prepare for an Northolt property is drawn to London Borough of Ealing’s validation standards and tuned to the UB5 constraints above. Here is what the drawing package covers and how the process runs from first survey to approval.
A basement conversion is one of the few ways to add genuine living space to a London home without touching the footprint above ground, but the drawings have to earn their keep in two very different disciplines at once. Converting an existing cellar into a habitable room is largely a building-regulations exercise, while digging out a new basement or lowering an existing floor is a structural undertaking that usually brings planning permission, underpinning design and neighbour consultation into the project as well.
DrawingsDirect prepares both types of basement drawing set for London homes — fit-out packages for existing cellars and full structural packages for new-dig or lowered basements — with waterproofing, means of escape, ventilation and Party Wall coordination built in from the first survey. As a chartered architectural technologist practice, we produce the structural design in-house rather than outsourcing it, so the drawings and the calculations arrive together, checked against each other, at a fixed fee.
Do I need planning permission for a basement conversion in London?
An internal conversion of an existing cellar — new floor, insulation, a habitable layout — often does not need planning permission, because the works sit entirely within the existing structure and do not change its external appearance. Digging out a new basement, lowering an existing floor to gain headroom, or enlarging the footprint under a garden usually does, particularly where excavation extends beyond the existing building line. Any external alteration needed to serve the basement — a front light well, a sunken external staircase, or altering the pavement or front garden — is also likely to need planning permission in its own right, even when the basement works themselves would not. In a conservation area, a front light well tends to draw closer scrutiny than the same feature elsewhere, since it changes the street-facing elevation and the pavement it sits within — one more reason we assess the whole scheme, not just the room below ground, before recommending a route.
Cellar conversion or new dig-out — which route fits your property?
The two starting points lead to very different drawing sets. A cellar conversion works with a void that already exists: the drawings focus on damp-proofing, insulation, headroom, natural or borrowed light, means of escape and a compliant layout, coordinated with building regulations rather than planning.
A new dig-out or floor-lowering project starts from a structural decision — how the existing foundations will be underpinned to allow excavation beneath them — and the drawings and structural calculations are produced together from the outset, since the sequence of underpinning, temporary works and waterproofing has to be engineered before a builder can safely start.
| Route | Typical scope | Planning position | Fee from |
|---|---|---|---|
| Existing cellar conversion | Fit-out of an existing void, no excavation | Usually building regulations only | £2,400 |
| Floor lowering / partial dig-out | Increases headroom within the existing footprint | Often needs planning permission | £3,200 |
| New-build basement or light well extension | New basement area beyond the existing footprint | Full planning plus Party Wall Act | £3,850 |
Basement Conversion Drawings in Northolt UB5 — FAQs
How much do basement conversion drawings cost in London?+
Does a basement conversion need planning permission?+
Will I need a party wall agreement for a basement conversion?+
Are structural calculations included in a basement conversion package?+
Do I need an architect for a basement conversion?+
Do I need planning permission for a rear extension in Ealing?+
What extra control applies in Bedford Park?+
How long does Ealing Council take to decide a householder application?+
Can you help with a loft conversion on a 1930s Ealing semi?+
How much do planning drawings cost in Ealing?+
Get your free Northolt planning assessment
Tell us your Northolt (UB5) address and ambition — we'll confirm feasibility, local constraints and a fixed fee within one working day.