You are about to buy a London house partly because of what it could become. We check the planning history, the designations and the permitted development rights, then tell you in writing what is realistic.
Photo: sludgegulper, BY-SA 2.0
Pre-purchase planning report
Fixed in writing after a free assessment of your property. Council planning fees are separate.
Every price is the total you pay. Checked 24 October 2026.
Listings say "scope to extend" about almost every London house. Whether it is true depends on facts that never reach the particulars: a previous owner's rear extension, a removed right under an Article 4 direction, a condition on the original estate permission, or a conservation area that cuts the permitted limits.
The most common surprise is a loft or extension already built. Permitted development counts earlier work toward the same allowance, so a house with a dormer already in place may have no volume left. A flat has no householder rights at all. A house on a corner plot has different side limits.
Our report reads the council's planning register for the address and its neighbours, checks the designations on the council map, and tests the likely extension, loft or outbuilding against the rules. It says plainly what is likely to be allowed, what would need an application, and what looks unlikely.
If the honest answer is that the plan you have in mind will not work, you learn it before you pay a deposit.
A written report you can show your solicitor, lender or partner.
Five facts do most of the damage to extension plans, and each can be found before you buy.
| Fact | Effect | Where we look |
|---|---|---|
| House is a flat or maisonette | No householder permitted development | Title and floor plan |
| In a conservation area | Larger rear limits and some roof rights removed | Council constraints map |
| Article 4 direction | Rights withdrawn for the listed works | Council Article 4 list |
| Earlier extension or loft | Allowance already used | Planning register, aerial photos |
| Original permission has a condition | May remove rights on the estate | Decision notice |
Sources: GPDO 2015, Schedule 2, Part 1 and your council's planning register.
Each figure links to the law or government source it comes from.
Under Class A, a single-storey rear extension may reach 3 metres on an attached house or 4 metres on a detached house, and 4 metres in height, without an application.
Source: legislation.gov.uk, GPDO 2015, Schedule 2, Part 1, Class A.1(f)Class A.1(g) allows 6 metres on an attached house or 8 metres on a detached house, subject to prior approval, but not on article 2(3) land such as a conservation area.
Source: legislation.gov.uk, GPDO 2015, Schedule 2, Part 1, Class A.1(g)Under Class B, a roof extension may add up to 40 cubic metres to a terraced house and 50 cubic metres to other houses.
Source: legislation.gov.uk, GPDO 2015, Schedule 2, Part 1, Class BSection 72(1) requires special attention to preserving or enhancing the character of a conservation area when a council exercises planning functions.
Source: legislation.gov.uk, Planning (Listed Buildings and Conservation Areas) Act 1990, s.72The fee for a lawful development certificate for proposed work is 50% of the fee for a planning application for the same work.
Source: GOV.UK, Fees for planning applications, paragraph 024London's 33 councils refused 1,141 of 4,784 large householder extension prior approval decisions in 2025-26, or 23.9%.
Source: GOV.UK, Planning applications statistics (PS1), summed by boroughLondon councils decided 24,758 householder applications in the year to March 2026.
Source: GOV.UK, Planning applications statistics (PS2)Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
No. It is a planning report, not a structural or condition survey. It tells you what the planning system is likely to allow. For the state of the roof, walls and drains, instruct a surveyor as well.
The research is desk-based, so it can be done within a few working days of receiving the address and your intended project. We ask for the listing and your scheme in a sentence or two, so tell us in the quote form.
Yes, as a record of what you checked. It is advice, not a legal opinion or a guarantee that permission will follow. A council decides each application on its merits.
If you buy the house and instruct us to draw the work, the £205 comes off the drawings fee. If you do not go ahead, the report still stands as your record.
Yes. Where permitted development looks possible, a lawful development certificate protects you at resale, and we say whether it is worth the cost. The council fee for a proposed-use certificate is half the planning fee.
Yes, and you may prefer to. Order the report on your shortlist, compare the results and bid with the facts. Each address is a separate report.
Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.