Floor Plans in London: House Plans and Drawings Explained
A floor plan is a scaled, top-down drawing of a building's layout, showing walls, doors, windows, room dimensions and fixed fittings as if the roof had been lifted off and you were looking straight down. In UK residential work it is one drawing within a wider set — alongside elevations, sections and a site plan — that together make up the "plans and drawings" a council or building control body needs to assess a project. On its own a floor plan tells you how the internal layout works; it is only when it is paired with elevations (external views) and, where structural work is involved, sections and structural calculations, that a design becomes buildable and consentable.
For a London homeowner, "floor plans" is often shorthand for the whole drawing package needed for a loft conversion, extension or internal reconfiguration. This page sets out exactly what a floor plan is, how it differs from the other drawing types, the scales and conventions councils expect.
What exactly is a floor plan?
A floor plan is a horizontal cross-section taken roughly 1.2 metres above finished floor level, showing everything that would be cut through at that height: walls, door openings, window openings, staircases, and fixed kitchen or bathroom layouts. It is drawn to scale — almost always 1:50 or 1:100 for residential work — so that anyone reading it, from a planning officer at Camden Council to a builder pricing the job, can measure a wall or a room directly off the page with a scale rule.
A proper floor plan is not a sketch. It shows existing structure in one line weight and proposed new structure in a different line weight or colour (usually red for new build work), so the council can see at a glance what is being kept and what is changing. Dimensions are given in millimetres, room areas are usually noted in square metres, and north points and grid references tie the plan back to the site plan.
How does a floor plan differ from an elevation, section or site plan?
These four drawing types are easy to confuse but serve different purposes, and a council or building control surveyor will expect all of them where relevant:
| Drawing type | What it shows | Typical scale |
|---|---|---|
| Floor plan | Internal layout, room by room, at each storey | 1:50 or 1:100 |
| Elevation | External faces of the building (front, rear, side) | 1:50 or 1:100 |
| Section | A vertical cut through the building showing floor-to-ceiling heights, roof pitch and construction build-up | 1:50 or 1:20 for detail |
| Site/location plan | The property in the context of its plot and street | 1:500 site plan, 1:1250 location plan |
A planning application to any London borough will almost always need a location plan at 1:1250 (so the site can be identified against Ordnance Survey mapping) plus a site plan at 1:500 showing the plot boundaries, and then floor plans, elevations and sometimes sections at 1:50 or 1:100 for the building itself. Missing any one of these is a common reason applications are returned as invalid by boroughs such as Southwark or Lambeth before they even reach a case officer.
What scale should my floor plans be drawn at?
Scale is not a stylistic choice — it is a technical convention that lets a reader take real measurements off a drawing. For domestic work the Royal Institute of British Architects and the Planning Portal both expect:
- 1:1250 or 1:2500 for the location plan, showing at least two adjoining roads
- 1:500 for the site plan, showing the whole property and its boundaries
- 1:50 or 1:100 for floor plans, elevations and sections of the building
- 1:20 or 1:10 for construction details such as eaves, staircases or steel connections
Every drawing must also state its scale and be accompanied by a scale bar, because plans are frequently printed or viewed at a different size to how they were drawn. A drawing marked "not to scale" is only acceptable for diagrammatic sketches, never for a formal planning or building regulations submission.
Do I need planning permission drawings or just building regulations drawings?
This is the single most common question homeowners across the 33 London boroughs ask, and the honest answer is: it depends on what you're doing. Many single-storey rear extensions, loft conversions and internal alterations fall under permitted development rights set out in the Town and Country Planning (General Permitted Development) Order 2015, Schedule 2, Part 1 — meaning no planning application is needed provided the project stays within the size, height and siting limits for that class. Larger extensions, front-facing changes, work in a conservation area, or anything on a flat or listed building will usually need a full planning application, decided by the borough within the statutory 8-week determination period (13 weeks for larger "major" applications).
Regardless of the planning route, almost every structural change to a house — a loft conversion, an extension, removing a load-bearing wall — needs Building Regulations approval, assessed against Approved Documents such as Part A (structure), Part B (fire safety), Part L (energy efficiency) and Part P (electrical safety). Floor plans for a building regulations submission are more detailed than planning drawings: they show insulation build-ups, structural openings, fire escape routes and drainage, because building control is checking the work will be safe and compliant, not just how it looks from the street.
- Measured survey of the existing property (or use of an existing survey)
- Existing floor plans for each storey, drawn to scale
- Proposed floor plans showing the new layout
- Existing and proposed elevations
- Site and location plans
Because the practice is chartered through the Chartered Institute of Architectural Technologists (CIAT), drawings are prepared to the same technical standard boroughs expect from a RIBA-registered architect, but at a fraction of the fee, because architectural technology firms typically run leaner overheads than traditional architecture studios.
Why do DIY or online "easy plans" templates usually fail?
A search for "easy plans" or free house plan generators turns up template-based tools that produce a floor plan-shaped image but not a technically accurate drawing. These templates typically fail for three reasons. First, they are not based on an accurate measured survey of the actual property, so dimensions are wrong the moment a builder or building control surveyor checks them on site. Second, they don't show construction detail — wall thicknesses, structural openings, insulation — which building control needs to discharge conditions or issue a completion certificate. Third, they carry no professional indemnity insurance or chartered sign-off, so if a council queries a measurement or a builder needs a revision, there's no accountable author to go back to.
For a London property, where conservation area designations, Article 4 directions and tightly packed terraces make small measurement errors costly, a measured survey by a chartered technologist is the difference between drawings that sail through validation at a borough like Wandsworth or Richmond upon Thames and drawings that bounce back as invalid, adding weeks to the process.
How long does it take to get floor plans drawn?
For a typical London terrace or semi, a measured survey takes half a day to a day depending on the property's size and complexity. Existing floor plans, elevations and site plans are usually turned around within one to two weeks, with proposed drawings following once the client has confirmed the layout. Building regulations drawings and structural calculations, where needed, add further time because they depend on a structural engineer's input on beam sizing. Planning applications then sit with the borough for up to 8 weeks (13 for major applications) before a decision is issued, and permitted development work can start as soon as drawings and, where relevant, a lawful development certificate are in place.
What information should a professional floor plan always show?
A floor plan produced for planning submission or building control is not just an outline of rooms. It should show, as a minimum: wall thicknesses (distinguishing masonry, timber stud and new partitions), the swing direction of every door, window and door reference numbers linked to a schedule, room names and net internal areas in square metres, staircase direction with number of risers, structural elements such as beams shown as dashed hidden lines, and a north point orientating the plan to the site. For a loft conversion or extension, the proposed floor plan should also flag which walls are being removed, which are new, and where any structural opening needs a lintel or steel beam, cross-referenced to structural calculations where the practice's Complete package includes them.
Boroughs including Ealing, Hackney and Croydon publish validation checklists that list exactly this level of detail as a minimum for a valid application; drawings that omit dimensions or room areas are one of the most common reasons an application is marked invalid on submission rather than being registered and assessed.
How does a measured survey turn into finished floor plans?
The process behind every set of floor plans on this site follows the same sequence. First, a chartered technologist visits the property and takes a full measured survey — laser-measuring every room, wall thickness, floor-to-ceiling height, window and door opening, and noting structural features such as chimney breasts or existing steel beams. This becomes the existing floor plan, the factual baseline everything else is checked against.
Second, the client's brief for the new layout is translated into a proposed floor plan, working through options for room sizes, circulation and how new openings or partitions interact with existing structure. Third, the drawings are checked against the relevant Approved Documents and, where planning permission is needed, against the borough's local plan policies (for example Camden's development management policies or Southwark's residential design standards) before submission. This staged approach, moving from an accurate survey through design to a compliant submission, is what separates a professional floor plan from a rough sketch, and it is the same RIBA Plan of Work logic, stages 1 to 4, from preparation through to technical design, that architects use, drawings-only service.
Frequently asked questions
What is the difference between a floor plan and a site plan?
A floor plan shows the internal layout of a building at a given storey, drawn at 1:50 or 1:100. A site plan shows the whole property and its plot boundaries in context, drawn at 1:500. Councils typically require both, plus a 1:1250 location plan, for a planning application.
Can I get floor plans without a full survey of my property?
You can, but the drawings will only be as accurate as the measurements you provide, which is risky for anything going to building control or a builder for pricing. A measured survey by a chartered technologist ensures the floor plans match the property exactly, which matters for compliant, buildable drawings across every London borough.
What scale are house plans usually drawn at?
Floor plans, elevations and sections are almost always drawn at 1:50 or 1:100 for residential work. Site plans use 1:500 and location plans use 1:1250, following Planning Portal and RIBA convention.
Do I need planning permission for a floor plan change inside my house?
Purely internal, non-structural changes usually don't need planning permission, but structural alterations such as removing a load-bearing wall still need Building Regulations approval under Approved Document A, regardless of whether planning permission is required.
How much do floor plans cost in London?
Who actually draws the floor plans — an architect or a technologist?
At this practice, drawings are prepared by MCIAT-chartered architectural technologists, who specialise in the technical detailing and regulatory compliance side of building design, working alongside architects and structural engineers where a project needs one.
Do floor plans need to show furniture?
Not for planning or building regulations purposes. Councils and building control are concerned with walls, structure, dimensions and compliance, not furniture layout, though many practices add indicative furniture to proposed plans to help clients visualise the finished space.
What's the difference between a floor plan and a floor plan drawing package?
A single floor plan is one drawing. A floor plan drawing package is the full set needed for a valid submission, existing and proposed floor plans for every storey, elevations, a site plan and a location plan, bundled together.
