Free permitted development check, England
Can I extend my house?
Tap your house on the map. We test your plot outline against conservation areas, Article 4 directions, listed buildings, National Parks and nine other designations, then show what each common project looks like under the permitted development rules.
- Each designation checked against your plot outline, with an evidence grade.
- "Not published by the council" where data is missing, never a false "none".
- A headline for eight common projects, with the limits to stay within, and the risk that a planning condition has removed your rights.
How it works
Three steps.
Step 1
Find and tap your house
Enter your postcode, then tap the roof of your home. We outline the registered plot under your tap (HM Land Registry) for you to confirm. We never locate a house from a postcode alone.
Step 2
We test the plot
13 datasets from planning.data.gov.uk are tested against that outline: whether it is inside, crossed by, or within a few metres of each boundary.
Step 3
You see the rules
Answer three questions (house or flat, house type, when it was built) and see each project's headline, the open items and the limits from the Order.
The rules by project
What the Order allows.
Limits from The Town and Country Planning (General Permitted Development) (England) Order 2015, as in force from 27 August 2026. Each has conditions and exceptions: see the project pages.
Rear extension
3 m or 4 m, or up to 6 m or 8 m with prior approval
The rulesSide extension
Single storey, half the house width
The rulesTwo-storey extension
3 m deep, 7 m from the rear boundary
The rulesLoft conversion
40 m³ or 50 m³ of extra roof space
The rulesGarden room or outbuilding
2.5 m near a boundary, 4 m or 3 m elsewhere
The rulesPorch
3 m² and 3 m high
The rulesFence, wall or gate
1 m by a road, 2 m elsewhere
The rulesDriveway
Porous surface over 5 m² at the front
The rulesWhat no automated check can see
Some councils do not publish their conservation areas, Article 4 directions or Tree Preservation Orders to the national planning data service. In our own sample of 300 random English postcodes (18 October 2026), the council published its own Article 4 data for 39% of them and its Tree Preservation Orders for 29%. Conditions on earlier permissions are not published nationally at all.
So we show what we checked, what we could not, and how to close each gap.
The only certain answer
A Lawful Development Certificate from your council. Once granted, the works are presumed lawful unless the facts change. The council fee is half the planning application fee (£274 for an extension from 1 April 2026) and the decision is due within 8 weeks. Anyone can apply direct to the council or through the Planning Portal.
Project Report, £14.99 (coming soon)
Every rule, tested on your figures.
For one house and every project you are planning: each rule in the Order tested against your figures, with the paragraph cited and an evidence grade, diagrams of the limits, planning history at your plot, and whether to apply for a Lawful Development Certificate.