Planning Application Drawings in London: Types, Scales, and What to Include

Location Plan (1:1250 scale): The location plan is an OS-based map extract at 1:1250 scale showing the application site and the surrounding street network. It must: Be based on a current Ordnance Survey map (not a hand-drawn sketch or a Google Maps print). Most architects obtain location plans from services such as Promap, Get-A-Map, or Digimap (EDINA). Show the application site boundary edged in red, including all the land that forms the application site (the house, garden, and any other areas affected by the proposed development). Show any other land in the applicant's ownership within the immediate vicinity edged in blue (this is relevant where the application involves works to an outbuilding or adjacent garage on land owned by the same person but not forming the domestic curtilage of the house). Include a north point and a scale bar. Show neighbouring properties and the public highway on at least two sides of the application site (to establish the spatial relationship of the site with its context).

Block Plan (Site Plan, 1:500 scale): The block plan (sometimes called the site plan) is a detailed plan of the specific application site at 1:500 scale. It shows: The outline of the existing building (house, outbuildings, garages) accurately drawn with approximate dimensions. The site boundary (curtilage) of the property. Neighbouring buildings and their proximity to the site boundary. The garden area, any significant trees (particularly protected trees or trees within the root protection area of a proposed extension), driveways, and access points. North point and scale bar. In London, the block plan should also show the position of any drainage manholes, sewer runs (particularly where the extension may affect a drain or sewer), or services that run through or near the site.

For most householder applications, the LPA does not require highly detailed topographical information on the block plan — but where the site has a significant level change (for example, a rear garden that slopes substantially relative to the house floor level), the approximate level change should be indicated.

Floor plans are plan-view drawings showing the layout of each floor level of the building, drawn as a horizontal section taken at approximately 900mm–1200mm above floor level (cutting through windows and doors to show the wall construction and opening sizes).

What existing floor plans must show: The layout of every floor level of the building as it currently exists. All external walls with their thickness indicated. All internal walls and partitions. All windows and doors, with the direction of swing (doors) and any fixed versus openable light subdivisions (windows). The position and width of all door openings. Staircases showing the direction of travel, number of risers, and handrail. Any fixed furniture that affects the spatial planning interpretation (bathroom sanitaryware, kitchen layout, fitted wardrobes). All chimneys, chimney breasts, and flue positions. North point and scale bar.

What proposed floor plans must show: All of the above for the proposed layout, clearly differentiating between existing elements that are retained, existing elements that are removed (typically shown hatched or struck through), and new elements. The proposed extension floor area, with key dimensions (depth of extension from the existing rear wall, width of extension, height of any level changes). Proposed windows and doors in new or altered positions. Proposed room uses for all new or altered spaces. Any new structural elements (steel beams, new load-bearing walls) shown in the correct position.

Scale and dimensions: Most householder applications submit floor plans at 1:50 or 1:100. 1:50 is preferred for complex layouts or where greater detail is needed (for example, to clearly show the internal arrangement of a small bathroom or galley kitchen). 1:100 is more common for the whole-house floor plan where showing all floors on a single sheet is the objective.

Elevation drawings show the external faces of the building as orthographic projections — the view of the building's exterior as if seen from a fixed horizontal position perpendicular to the wall face (not a perspective drawing).

Which elevations must be shown: The LPA requires existing and proposed elevation drawings for all faces of the building that are affected by the proposed development. For a rear extension, this typically means: Rear elevation (existing and proposed): showing the existing rear face of the house, the proposed extension addition, and any new windows and doors. Side elevation (existing and proposed): showing the side face of the extension (where the extension has a visible side face).

In some London boroughs (particularly where the application is in a Conservation Area or where the streetscape design of the front elevation is relevant), front elevation drawings are also required even if the front elevation is not being altered — to show context.

What elevation drawings must show: All existing and proposed features on the elevation face — windows (individual panes and opening lights), doors, ventilation grilles, rainwater pipes, fascia and soffits, any decorative features. The existing ground level (as a horizontal datum line) and the proposed finished floor level (if different from the existing). Key annotated dimensions: the height of the proposed extension at eaves level (from existing ground level); the overall height of the proposed extension (at ridge or highest point); the projection depth of the extension (how far it extends from the original rear wall); the height of any new windows (from finished floor level to head); and the height of any new doors. The relationship between the proposed addition and the adjoining properties (where the proposed addition rises above or abuts the party wall or boundary, show the height relationship clearly). Materials annotation: the proposed external materials should be annotated on the elevation drawing (or in a separate materials schedule) — for example, "Reclaimed London stock brick to match existing" or "K Rend silicone render, colour to be approved" or "PPC aluminium bi-fold door system, colour Grey 7016".

What NOT to show on planning elevation drawings: Detailed technical specification (insulation, structural elements, building services — these belong on Building Regulations drawings). Section cuts or section arrows on elevation drawings (sections are a separate drawing type).

Section drawings: Section drawings show vertical cuts through the building — they reveal the internal heights, the relationship between floor levels, the roof construction profile, and the spatial relationship between existing and proposed elements. Section drawings are required for most loft conversion, basement conversion, and dormer applications where the internal vertical dimension is key to understanding the development.

A typical section drawing for a loft conversion shows: The existing and proposed roof structure in section. The new floor level within the loft. The head height at the highest point of the loft space (typically at the ridge). The position of the new staircase (and its relationship to the floor below). The depth of the dormer cheeks in relation to the existing roof slope. The junction between the new floor structure and the existing party wall at each side.

For a straightforward rear extension, a section drawing through the extension (showing the foundation depth, floor-to-ceiling height, and roof construction in profile) is helpful and is requested by some London borough planning departments, though it is not universally mandated for simple householder applications.

Design and Access Statement (DAS): The DAS is a written document submitted with the planning application that explains the design thinking behind the proposal. For a householder application, the DAS is typically brief — 2–5 pages. Key content includes: Introduction to the site and the proposed development. Policy context (reference to the relevant Local Plan policies, the Conservation Area Appraisal where applicable, the London Plan policies relevant to the development). Design rationale: why the proposed design, form, materials, and layout have been chosen. How the proposed extension responds to the character of the Conservation Area or the streetscape. Access: any changes to disabled access, or confirmation that access provisions are maintained. Sustainability: reference to any energy efficiency measures, green roof, or sustainable drainage measures proposed as part of the development.

A weak DAS that simply describes what is proposed without explaining why, or that fails to reference the relevant policy documents, is a common avoidable deficiency in London householder planning applications. A well-written DAS that demonstrates engagement with the Conservation Area Appraisal, the local planning context, and the design aspirations of the LPA significantly improves the quality of the planning submission.

The confusion between planning drawings and Building Regulations drawings is extremely common among London homeowners embarking on an extension or renovation project. The two sets of drawings serve fundamentally different purposes and are submitted to different authorities:

Planning drawings: Submitted to: the Local Planning Authority (LPA) — the London borough's planning department. Purpose: to demonstrate the design intent, the visual character, and the policy compliance of the proposed development. Planning permission is about whether the development should happen in principle — the design, the scale, the materials, and the impact on the Conservation Area and neighbours. Level of technical detail: moderate — sufficient to show the LPA what the development will look like and how it relates to its context. Technical specifications (insulation thickness, structural calculations, drainage design) are not required. When approved: planning permission is granted before work starts. It establishes the legal right to carry out the development in principle.

Building Regulations drawings: Submitted to: the Building Control body — either the LPA's Building Control department or an Approved Inspector (a private building control provider). Purpose: to demonstrate that the proposed construction meets the technical requirements of the Building Regulations (structural stability, fire safety, energy efficiency, ventilation, drainage, etc.). Building Regulations approval is about whether the development can be safely built and will perform correctly. Level of technical detail: high — showing insulation specifications and U-values, structural beam sizes and padstone specifications, drainage run gradients and pipe sizes, fire escape strategy, staircase dimensions, party wall construction details, and any specialist system specifications. When approved: Building Regulations approval (in the form of an initial plan approval and then inspections at key stages of construction) runs concurrently with and after planning permission. Both are required before construction is complete and the building is occupied.

The practical sequence: Appoint architect to prepare planning drawings → Submit planning application → Await planning decision (typically 8 weeks) → While awaiting planning decision (or after receipt) appoint structural engineer → Prepare Building Regulations drawings → Submit Building Regulations application → Award contract to builder and commence work on site.

Some London contractors begin work before Building Regulations drawings are approved (under a Building Notice rather than a Full Plans application) — this is legally permissible but carries risk: if the building control inspector requires changes to the construction method, costly remediation may be required. For complex structural or fire safety work, a Full Plans application with pre-approved drawings is strongly recommended.