Planning Drawings vs Construction Drawings: What's the Difference and What Do You Need?

**Purpose of planning drawings**:

Planning drawings are produced to support a planning application — they show what you intend to build and its relationship to the site, the neighbouring properties, and the street scene. Their purpose is to allow the planning authority to assess the proposal against planning policy. They are not construction documents.

**What planning drawings must include** (for a standard householder application):

*Site location plan*: Usually at 1:1250 scale, showing the application site (red-line boundary) in the context of the surrounding street network and nearby properties. Typically produced from an Ordnance Survey base map.

*Block plan (site plan)*: At 1:500 or 1:200 scale, showing the existing and proposed footprint of the building in relation to the site boundaries, adjacent buildings, and access.

*Existing floor plans*: Plans of the existing building at each affected level — typically at 1:50 or 1:100 scale, showing room layout and key dimensions.

*Proposed floor plans*: Plans of the proposed building, showing the changes to the layout, extensions, or new structure.

*Existing and proposed elevations*: All external faces of the existing and proposed building — typically showing the proposed extension in context with the existing building and with the neighbouring properties.

*Existing and proposed sections*: Cross-sections through the building showing internal heights and the relationship between floors, roof, and ground level.

*Roof plan*: For extensions and conversions, a plan showing the proposed roof form.

**What planning drawings do NOT include**:

• Planning drawings are intentionally limited in scope — they show the general form, massing, and relationship to the context, but they do not show:
• •Structural information (foundation type, beam and column positions, size of structural members)
• •Construction details (wall build-up, insulation specification, junction details)
• •MEP (mechanical, electrical, and plumbing) information
• •Building materials specification beyond a general description (e.g., 'matching brick' or 'render finish')
• •Room dimensions in detail
• •Internal joinery, kitchen and bathroom layouts, or finishes

This means that while an approved planning drawing set is sufficient to obtain planning permission, it is not sufficient to price the works accurately, to obtain Building Regulations approval, or to build from.

**Who produces planning drawings**:

• For most London householder projects (loft conversions, extensions, changes to layout), planning drawings are produced by:
• •An architect (RIBA or ARB registered) — for the full service
• •An architectural technician or architectural designer — typically lower cost, adequate for straightforward planning drawings
• •A planning consultant (for complex applications where planning strategy is as important as design)

*Cost of planning drawings for a standard London rear extension*: £800–£3,000 depending on complexity and scope.

**Purpose of building regulations drawings**:

Building regulations (BR) drawings are produced to demonstrate compliance with the Building Regulations — they are submitted to Building Control (either Local Authority Building Control or an Approved Inspector) for approval under a Full Plans application, or provided as background information under a Building Notice.

Building regulations drawings expand significantly on planning drawings — they show how the building will be built in accordance with the Technical Standards (Parts A through R of the Building Regulations).

**What building regulations drawings must include**:

*Construction details at the relevant junctions*: Wall-to-floor junction (Part L insulation continuity and cold bridge prevention); eaves detail (ventilation, insulation); party wall junction (Part E acoustic performance); roof detail (insulation, vapour barrier, ventilation).

*Structural information*: Foundation type, depth, and size (Part A); floor structure (joists, beam sizes, span tables); roof structure (rafters, purlins — or a roof truss manufacturer's layout); structural steel positions and reference to structural engineer's calculations.

*Drainage layout*: Below-ground drainage runs, inspection chambers, and connection points (Part H).

*Ventilation strategy*: Kitchen extract, bathroom extract, whole-house ventilation approach (Part F).

*Thermal specification*: U-values for all building elements — walls, roof, floor, windows and doors; overall SAP or thermal bridging assessment (Part L).

*Fire strategy*: Means of escape, smoke detection, emergency lighting if relevant (Part B).

*Services information*: Electrical installation layout (circuits, consumer unit position) — not full electrical engineering drawings but sufficient for Part P compliance; boiler and heating system position.

**Who produces building regulations drawings**:

• Building regulations drawings require more technical knowledge than planning drawings — they are typically produced by:
• •An architect (who offers a full service from RIBA Stage 2 design through to Stage 4 technical design)
• •A structural engineer for the structural elements
• •A specialist M&E engineer for complex projects (most domestic projects do not need one)
• •An architectural technician with building regulations experience

*Cost of building regulations drawings for a standard London rear extension*: £1,500–£5,000 (in addition to planning drawings, if not already included in an architect's scope).

**Full Plans vs Building Notice**:

• •A Full Plans application involves submitting the building regulations drawings to Building Control before works start — they are checked and conditional approval is granted. Building Control then inspects at key stages. This is the preferred route because it provides advance certainty about compliance.
• •A Building Notice does not require drawing submission — the contractor notifies Building Control and inspections happen during the works. This is faster but provides less certainty — compliance issues discovered mid-build can be expensive to resolve.

For any project with structural works, drainage works, or MEP works in London, Full Plans is strongly recommended.

**What construction drawings are**:

Construction drawings are the full technical document set from which the contractor builds. They expand on the building regulations drawings to include the information needed to actually construct and price the works — room dimensions, specification, materials, finishes, joinery details, and kitchen and bathroom layouts.

For a major London project (a rear extension plus full interior refurbishment), the construction drawing set might include:

• •*Demolition plan*: Which walls, partitions, and elements are to be removed
• •*Proposed floor plans at 1:50 or 1:100*: All levels with room names and key dimensions
• •*Reflected ceiling plans*: Layout of lighting, ceiling features, ventilation extract positions
• •*Internal elevations*: Kitchen walls showing unit positions; bathroom walls showing sanitary ware and tiling; feature walls
• •*Section drawings*: Through the staircase, through the extension, through key construction junctions
• •*Detailed joinery drawings*: Bespoke joinery (fitted wardrobes, built-in storage, stair details)
• •*Specification schedule*: Finishes specification by room — floor, wall, ceiling material; sanitary ware models; kitchen unit supplier; window specifications
• •*Drainage layout (above and below ground)*: Connection to existing drain, new drain runs, gully positions
• •*Lighting and electrical layout*: Socket and switch positions, lighting circuit layout
• •*Structural engineer's drawings*: Foundation details, steel schedules, column and beam details

**Who produces construction drawings**:

An architect offering a full RIBA Stage 1–5 service includes construction drawings as part of Stage 4 (Technical Design). The structural engineer and other specialists produce their elements separately and these are coordinated by the architect.

*Cost*: Full architectural service from concept to construction information for a standard London rear extension: typically 8–15% of construction cost. For a project at £80,000 construction cost, this equates to £6,400–£12,000 in architect's fees.

**The design-and-build contractor as an alternative**:

• For many London homeowners, a design-and-build approach through a principal contractor like RCB is a practical and cost-effective alternative to a separately appointed architect. In a design-and-build model:
• •The contractor (or their in-house designer) produces the planning drawings
• •An architectural technician or the contractor's design team produces the building regulations drawings
• •The structural engineer (appointed through the contractor) produces the structural design
• •The contractor's detailed scope of works and specification replaces many elements of the full construction drawing set

This integrates design and pricing — the scope of works and price are developed together, ensuring that what is designed is what can be priced and built within budget.