MCIAT chartered drawings · Fixed fees across all 33 London boroughs

Free 2026 London Planning ReportBasement Conversion Drawings in Eltham SE9

Loft conversion with skylights in an interwar house in Eltham SE9, Royal Borough of Greenwich
Eltham · SE9 · Greenwich

Basement Conversion Drawings in Eltham SE9

Fixed-fee, MCIAT-chartered basement conversion drawings for Eltham (SE9) homeowners — Royal Borough of Greenwich validation and local constraints handled from the start.

Free Eltham planning assessment

Tell us your Eltham (SE9) address and project. A fixed quote and free planning appraisal land within one working day.

No obligation · No spam · Reply within 1 working day

Eltham (SE9) sits in the Royal Borough of Greenwich and is best known for the Progress Estate at Well Hall — a 1915 Arts-and-Crafts garden suburb that inspired much interwar housing and has been a conservation area since 1971. An Article 4 direction covers the estate, so on those streets even small external changes need consent, and rear and loft projects have to be handled with real care for the original detailing.

Away from the estate, much of Eltham is consistent interwar semi-detached and terraced housing where side-return, rear and loft projects are the staple. The district also carries the setting of Eltham Palace and its listed gardens. We check where an Eltham property sits relative to the Progress Estate Article 4 area and the palace setting before recommending a permitted-development or full-application route under Greenwich's guidance.

Loft conversion with skylights in an interwar house in Eltham SE9, Royal Borough of Greenwich
Isometric illustration of a Eltham SE9 home basement conversion drawings design
Proposed floor plan
Eltham SE9

Planning in Eltham (SE9): what to know before you apply

Eltham's Progress Estate at Well Hall carries a conservation-area designation and an Article 4 direction (1973), so permitted-development rights are removed across the estate and external changes need planning permission. Elsewhere in SE9 many interwar houses retain PD rights for rear and loft work, but the consistent frontages and the setting of Grade I listed Eltham Palace mean elevation and roof changes are assessed closely. We confirm which controls apply to a specific address before drawing.

Typical Eltham housing stock

The 1915 Arts-and-Crafts cottages and greens of the Progress Estate around Well Hall Road, interwar semi-detached and terraced housing across much of Eltham, and later post-war housing toward Mottingham and New Eltham.

Streets we regularly draw for in Eltham

Well Hall Road · Court Road · Eltham High Street · Ross Way

Basement Conversion Drawings for Eltham (SE9) homes: the package and the process

Every basement conversion drawings we prepare for an Eltham property is drawn to Royal Borough of Greenwich’s validation standards and tuned to the SE9 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.

Basement conversion drawing packages in London
RouteTypical scopePlanning positionFee from
Existing cellar conversionFit-out of an existing void, no excavationUsually building regulations only£2,400
Floor lowering / partial dig-outIncreases headroom within the existing footprintOften needs planning permission£3,200
New-build basement or light well extensionNew basement area beyond the existing footprintFull planning plus Party Wall Act£3,850
FAQ

Basement Conversion Drawings in Eltham SE9 — FAQs

How much do basement conversion drawings cost in London?+
Packages start from around £2,400 for converting an existing cellar and rise to around £3,850 for a full planning and structural package covering a new dig-out or floor-lowering project. We agree the fee upfront once we know which route your property needs.
Does a basement conversion need planning permission?+
Converting an existing cellar often does not, since the works are internal. Digging out a new basement, lowering a floor, or adding external features such as a front light well usually does. We check your specific property before recommending a route.
Will I need a party wall agreement for a basement conversion?+
Almost always, if excavation takes place near or below a shared boundary. The Party Wall etc. Act 1996 requires notice to adjoining owners before underpinning or excavation begins, and we identify likely notifiable neighbours from the drawings.
Are structural calculations included in a basement conversion package?+
Yes — underpinning sequences, steel beams and retaining structures are calculated in-house as part of the same fixed fee, so the drawings and the engineering are never produced separately.
Do I need an architect for a basement conversion?+
No. As an MCIAT-chartered architectural technologist practice we produce the same council-accepted drawings as an architect, typically around 30% cheaper, with structural design coordinated in-house rather than outsourced.
Do I need planning permission for an extension in Greenwich?+
It depends on the area. The interwar and post-war suburbs toward Eltham and Kidbrooke often retain permitted development rights for rear extensions and lofts, while the historic core around West Greenwich and Blackheath sits within conservation areas where those rights are removed. We check your address against the designations first and can confirm permitted development with a Lawful Development Certificate.
How does the Maritime Greenwich World Heritage Site affect my project?+
Proposals within the World Heritage Site or its buffer zone are assessed against the setting of Maritime Greenwich, where the council protects townscape and long views toward the Royal Observatory. It doesn't rule out an extension, but roof-level and prominent works near the site need careful, context-led design. We confirm whether the setting applies to your address before drawing.
Can I extend a home in Blackheath or Westcombe Park?+
Yes, but these conservation areas carry strong design control over materials, rooflines and front elevations, and sloping sites around Blackheath and the Greenwich hills shape what works. We design context-led drawings that respond to the area's Georgian and Edwardian character and the topography, which is what carries applications to consent here.
How long does the Royal Borough of Greenwich take to decide?+
Greenwich determines most householder applications within the statutory eight-week period once validated; World Heritage Site, conservation and protected-view cases can involve additional consultation. We prepare submissions to the council's validation checklist to avoid the drawing queries that cause most delays.
How much do planning drawings cost in Greenwich?+
We agree a fixed fee before starting, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until Greenwich approves. A suburban Eltham extension and a West Greenwich heritage application differ in the evidence required, so we quote once we understand your address and project rather than by the hour.
Free Fixed Quote

Get your free Eltham planning assessment

Tell us your Eltham (SE9) address and ambition — we'll confirm feasibility, local constraints and a fixed fee within one working day.