Choose the application route before ordering
An extension may require householder planning permission, qualify for permitted development, need prior approval under a specific route, or be the subject of a proposed Lawful Development Certificate. Flats, maisonettes, listed buildings, Article 4 areas and properties with restrictive conditions need particular care.
| Route | What the plans must establish |
|---|---|
| Householder planning permission | The site plus the complete existing and proposed extension |
| Larger-home-extension prior approval | The site, existing enlargements, proposal and specified dimensions |
| Proposed Lawful Development Certificate | A precise proposal that can be tested against the relevant legal rules |
| No planning submission | Keep scaled design records; consider whether a certificate would provide useful certainty |
| Listed or protected property | Obtain advice on planning and any separate consent |
The likely extension drawing pack
Typical scales are conventions rather than universal requirements. Check the receiving authority's current list.
| Document | Typical scale | Purpose |
|---|---|---|
| Location plan | 1:1,250 or 1:2,500 | Identifies the application site |
| Existing and proposed site/block plan | 1:200 or 1:500 | Shows the extension in the plot |
| Existing and proposed floor plans | 1:50 or 1:100 | Shows walls, rooms, openings and demolition |
| Existing and proposed elevations | 1:50 or 1:100 | Shows appearance, height, openings and materials |
| Roof plan or section | 1:50 or 1:100 | Explains roof form, level change or close relationships |
Draw the location-plan boundary around the right site
For a normal householder proposal, the red line commonly follows the residential site, including the house, garden and necessary access, rather than a tight box around the new room. The governing test is the land needed for the application, not automatically everything on the ownership title.
What the block or site plan should show
The detailed plan should distinguish the proposed footprint from the existing house and show how it relates to the whole plot. An unannotated OS base is not a proposed site plan.
- Existing house and relevant outbuildings
- Proposed extension footprint and overall dimensions
- Distances to relevant boundaries and nearby buildings
- Access, parking, paths and hardstanding
- Trees, hedges, walls, fences and landscaping affected
- Existing and proposed levels on sloping land
- North, scale, scale bar, title and revision
Building drawings are separate from the map
Floor plans show the internal and external footprint, elevations show appearance and height, a roof plan explains the roof form and a section explains levels or vertical relationships. These drawings require measured building and design information that a topographic map cannot supply.
Extra detail depends on the extension
A rear or side extension calls for clear boundary distances and remaining garden; a two-storey addition places more weight on height, windows and roof form; a sloping site needs levels and sections; a rural or very large plot may need wider 1:2,500 context plus a detailed site plan.
Check restrictions and other approvals
Permitted-development rights differ by UK nation and can be narrowed by property type, previous extensions, designation, Article 4 direction or planning condition. Planning permission also does not replace building regulations approval, listed building consent, highway approval, party-wall responsibilities or private rights.
Extension submission checklist
Coordinate the maps and architectural drawings as one revision-controlled set before uploading.
- Correct application, prior-approval or certificate route selected
- Authority's current validation list checked
- Existing extensions and outbuildings recorded
- Red line includes the necessary site and access
- Proposed footprint agrees with floor plans, roof and elevations
- Heights, depths, widths and boundary distances agree
- Scale, paper size, north and mapping licence checked
- Drawing titles, numbers, dates and revisions controlled
- Final PDF tested at its stated scale
Local requirements may differ. Check the current validation list for your planning authority before submitting.
Evidence checked 18 August 2026
Official sources and further reading
Planning requirements differ across the UK. The scope label on each source shows where it applies; always use the current rules for the authority receiving the application.
Questions people also ask
Do I normally need both a location plan and block plan for an extension?
Usually when the application involves building work. In England the location plan is the national minimum; the closer site plan is commonly required to show the extension in its plot.
Is a block plan enough on its own?
Usually not. It cannot replace the floor plans, elevations, roof plan or sections needed to describe the design.
If the extension is permitted development, do I need maps?
Not for a full planning application, but a prior-approval process or Lawful Development Certificate can still require a plan and dimensioned drawings.
Should the red line go around the house or only the extension?
It must enclose the application site and all land necessary for the proposal. For a normal residential extension that is usually wider than the new footprint.
Does the planning map replace a measured survey?
No. Accurate building dimensions, boundary clearances and levels may require measured survey work.
Ready to create your planning map?
Search by postcode or address, choose the scale and coverage, add your application boundary and download from UKPlanningMaps.com. For help with an unusual site, call 01856 898 022.
Create your plan at UKPlanningMaps.com ↗