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Free 2026 London Planning ReportNew Build Drawings in Forest Hill SE23

Loft conversion with skylights in a Victorian villa in Forest Hill SE23, London Borough of Lewisham
Forest Hill · SE23 · Lewisham

New Build Drawings in Forest Hill SE23

Fixed-fee, MCIAT-chartered new build drawings for Forest Hill (SE23) homeowners — London Borough of Lewisham validation and local constraints handled from the start.

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Forest Hill (SE23) in Lewisham is a hilly Victorian suburb of substantial villas and terraces around the Horniman Museum and gardens. The steep topography and the Forest Hill conservation area together shape what works for extensions and loft conversions here.

Within the conservation area an Article 4(3) direction removes specified permitted development rights, so many changes that would be permitted elsewhere need a full application designed to the area's Victorian character; the steep plots add overlooking and level-change considerations. Lewisham's small-HMO Article 4 direction is a further control on conversions.

Loft conversion with skylights in a Victorian villa in Forest Hill SE23, London Borough of Lewisham
Isometric illustration of a Forest Hill SE23 home new build drawings design
Proposed floor plan
Forest Hill SE23

Planning in Forest Hill (SE23): what to know before you apply

The Forest Hill conservation area carries an Article 4(3) direction removing specified householder permitted development rights, so loft and extension projects within it generally need a full planning application rather than relying on permitted development. The steep hillside plots and mature trees around the Horniman add design and TPO considerations, and Lewisham's small-HMO Article 4 direction restricts new conversions.

Typical Forest Hill housing stock

Substantial Victorian villas and terraces climbing the hills around the Horniman Museum, with later Edwardian and interwar houses on the higher ground toward Honor Oak.

Streets we regularly draw for in Forest Hill

London Road · Dartmouth Road · Honor Oak Road · Devonshire Road

What SE23 is actually built of

Measured from 377 classified residential buildings in SE23, not from a description of the area.

Forest Hill SE23 housing mix

Residential building form across the SE23 postcode district, from 377 classified buildings.

Attached on more than one side50%
Attached on one side39%
Detached11%
Median building footprint67 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate1.8
Buildings classified377

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-08-17.

New Build Drawings for Forest Hill (SE23) homes: the package and the process

A new dwelling is a full application rather than a householder one, and the drawing set reflects that: site layout with levels and boundaries, floor plans and elevations for the new building, sections showing how it sits in the ground, and street-scene elevations placing it against what is already there.

Two packages follow the approval — the planning set and the construction set — and they have to stay in step. Foundation design, drainage strategy, thermal performance and fire strategy are drawn for Building Control against the same geometry that was granted permission, so the built house matches the approved one.

An infill plot is designed against its neighbours. Plot width, the building line either side, and the ridge heights next door set what the new house can be — and on a tight urban site those constraints usually shape the design more than the brief does.

Is my plot suitable for a new build in London?

A feasibility assessment looks at plot size and shape, access, existing boundary conditions, relevant planning policy for the borough, and the likely impact of a new dwelling on neighbouring properties before any design work begins. Infill plots — a gap between existing buildings on a street — and backland plots — a garden or yard site behind existing houses, reached by a shared access — each raise different issues: infill schemes are usually judged on how well they match the scale, spacing and character of the street, while backland schemes are judged heavily on overlooking, garden loss for neighbours, and whether the access arrangement is acceptable. A feasibility study gives an honest view of whether a scheme is likely to succeed before you commit to full drawings.

What does pre-application advice add to a new build project?

Pre-application advice is a formal, paid process most London boroughs offer, where planning officers give written feedback on a proposed scheme before a full application is submitted. For a new build — where the principle of development itself is often the main issue, not just the design details — this feedback can be invaluable: it surfaces concerns around density, massing, daylight and sunlight or heritage context early enough to be addressed in the drawings, rather than discovered for the first time as a refusal reason months into a full application. We prepare and submit pre-application enquiries as part of the new build service where it is likely to strengthen the eventual planning application.

How do daylight, sunlight and overlooking affect a new build design?

London boroughs assess new dwellings against their effect on the daylight and sunlight reaching neighbouring homes and gardens, commonly using the 45-degree rule as an initial check on a proposal's massing and position relative to neighbouring windows, alongside more detailed daylight and sunlight assessment on sensitive sites. Overlooking and loss of privacy from new windows, upper floors or roof terraces are assessed similarly, and often shape decisions on window placement, floor-to-floor heights and the overall footprint and massing of the new building. Designing with these constraints from the earliest sketch stage, rather than adjusting for them after a refusal, is one of the main advantages of instructing feasibility and pre-application work before a full planning set.

New build project stages
StageWhat it establishesTypical fee guide
FeasibilityWhether the plot can support a new dwelling and the likely constraintsQuoted individually, from within the £2,500 new build fee
Pre-application adviceWritten borough feedback on the scheme before a full applicationQuoted individually alongside the planning fee
Full planning drawingsThe complete drawing set submitted for planning permissionFrom £2,500
Building regs and structuralConstruction-ready drawings and calculations for buildingFrom £2,200–£3,850, quoted once planning is settled
Sheet from a new build drawings package drawn for a Forest Hill property in SE23, showing the existing and proposed arrangement at scale
A sheet from the new build drawings package we submit to London Borough of Lewisham for Forest Hill (SE23) properties.
FAQ

New Build Drawings in Forest Hill SE23 — FAQs

How much do new build drawings cost in London?+
New build drawings start from £2,500 for feasibility and a full planning drawing set on a straightforward infill or backland plot, with building regulations and structural drawings quoted separately once the planning design is agreed.
Can any garden or backland plot be built on in London?+
Not necessarily — backland and garden plots are assessed on access, overlooking, loss of garden amenity for neighbours and borough policy, and a feasibility assessment gives an honest early view of whether a scheme is likely to be supported.
Do I need pre-application advice before a full new build application?+
It is not mandatory, but for a new dwelling — where the principle of development is often the main issue — pre-application advice can surface concerns early enough to address them in the design, reducing the risk of refusal.
Do you handle building regulations and structural drawings for a new build, or only planning?+
Both — the full new build service covers planning, building regulations and structural drawings from one in-house team, so the design stays consistent from feasibility through to construction-ready drawings.
How long does a new build project take from feasibility to planning permission?+
This varies with site complexity and whether pre-application advice is sought, but a full planning application is determined within the statutory period the borough applies to the application type, once submitted via the Planning Portal.
Do I need planning permission for a side-return extension in Lewisham?+
On the Victorian and Edwardian terraces of Brockley, Forest Hill and Hither Green a single-storey side-return or rear extension can fall within permitted development, so a full application isn't always needed. Conservation areas such as Blackheath, Brockley and Telegraph Hill restrict this. We check your street's designation first and can confirm permitted development with a Lawful Development Certificate where it qualifies.
What does Lewisham's borough-wide HMO Article 4 direction affect?+
Lewisham applies a borough-wide Article 4 direction removing permitted development rights for change of use to an HMO (C3 to C4), so a conversion to a house in multiple occupation needs a full application anywhere in the borough. It doesn't affect a standard family extension or loft, but we confirm whether it applies to your intended use before advising on a route.
Can I convert the loft on my Lewisham terrace?+
Usually, yes. The terraces of Brockley, Forest Hill and Hither Green suit hip-to-gable and dormer loft conversions, which frequently qualify as permitted development within the volume limits. Outside the conservation areas this is often the quickest route. We confirm eligibility against those limits and any designation, then produce the planning and building-regulations drawings.
How long does Lewisham Council take to decide?+
Lewisham determines most householder applications within the statutory eight-week period once validated; conservation cases can attract additional consultation. The dense terraced streets are party-wall-sensitive, so the commonest delay is a drawing query — we prepare submissions to the council's validation checklist to keep them moving.
How much do planning drawings cost in Lewisham?+
We agree a fixed fee before starting, usually around 30% below an architect's fee for the same council-accepted drawings, with free redraws until Lewisham approves. A side-return, a loft and a conservation-area scheme differ in complexity, so we quote once we understand your street and project rather than charging by the hour.
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