Can you extend this house? A report for £185
The extension that sold you the house may not be allowed. Before you offer, we check what you could build there, what has been built already and what stands in the way.
£185 fixed fee, no VAT to add
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The short answer
A pre-purchase report tells you what you could extend or convert on a particular house, before you buy it. It checks planning rights, the planning history, designations and the size of earlier work, then gives a plain verdict on the project you have in mind. Our fee is £185, no VAT to add.
Pre-purchase “can I extend?” report
from £185
- Fixed fee
- £185
- VAT
- None to add
- The planning history of the house: earlier extensions, conditions and decisions on the same plot
- Designations at the address: conservation area, listed status, Article 4 directions, trees and flood zone
- Whether permitted development rights are intact, removed by condition or limited by earlier work
- The largest rear, side or loft extension the rules appear to allow, with the route to get it
- A note on whether past work looks lawful, and what a buyer’s solicitor should ask for
- A plain-English verdict on your project and a suggested next step
£185. A starting fee: we confirm one fixed figure after checking your address. The council’s own fee, where there is one, is paid to the council.
Get my fixed feeOur fee here is £185, no VAT to add. The main page for this service is on our sister site Fixed Fee Plans, run by the same team.
How the report is made
Send the listing
You send the address or the listing link, and what you hope to build.
Read the record
We read the council’s planning register for the house and its neighbours.
Check the rights
We test your idea against permitted development, allowing for earlier extensions and any removed rights.
Look at the house
From the listing photos and mapping, we look at plot shape, garden depth and neighbours’ extensions.
Verdict
You get the answer, the route and the questions to put to the seller.
Why a rear extension may already be used up
Permitted development counts everything added to the original house. Under Class A, a rear extension is limited to 3 metres on a terrace or semi and 4 metres on a detached house, and the total enlargement, new and existing, must stay within the limits. A house that has already been extended may have nothing left.
Roof space works the same way. A loft addition is capped at 40 cubic metres on a terrace and 50 on any other house, counting earlier additions. An agent’s “scope to extend” says nothing about either number.
Rights can be taken away
Permitted development rights can be removed by a condition on an earlier planning permission or by an Article 4 direction, as the Planning Practice Guidance explains. Some estates carry such conditions, and sale particulars rarely mention them.
We read the decision notices for your house and the original development, because that is where a condition would sit. If rights are removed, the extension is still possible, but it needs a planning application and the outcome is a judgement, not a right.
- A condition on the original estate permission removing rights
- An Article 4 direction for the street or conservation area
- Earlier extensions that have used the allowance
- A flat or maisonette: the householder rights do not apply in the same way
Work that was never lawful
If the house already has an extension, check that it was lawful. Where it was built under permitted development, a Lawful Development Certificate is the proof; where it was built without permission, the buyer may inherit an enforcement risk. The certificate guidance explains what a certificate does and does not cover.
The report tells you what to ask the seller’s solicitor for: certificates, decision notices and completion certificates. If the paperwork is missing, our retrospective application and regularisation services can put it right after you buy.
The rules the report tests
3 m / 4 m
Deepest single-storey rear extension permitted: terrace or semi, detached.
40 m³
Largest roof-space increase on a terrace, with 50 cubic metres on other houses, counting earlier additions.
50%
Most of the garden that buildings other than the original house may cover.
Total
The enlarged part together with any existing enlargement it joins must stay within the limits.
2 ways
Planning authorities remove permitted development rights by condition or by an Article 4 direction.
Source: Planning Practice Guidance: when is permission required? (GOV.UK)
s192(4)
A granted certificate for proposed development is presumed lawful unless something material changes.
Source: Planning Practice Guidance: lawful development certificates (GOV.UK)
s55(2)(a)
Works affecting only the interior of a building are not development.
Source: Town and Country Planning Act 1990, section 55 (legislation.gov.uk)
Questions about the report
Can you tell me if I will get permission?
We cannot promise a decision, because the council decides. The report tells you whether the extension is permitted development, what could block it and how likely each route looks from the history.
Do I need to see inside the house?
Not for the report. We work from the planning record, mapping and the listing. If you go on to buy, a measured survey gives exact dimensions for drawings.
Is this the same as a conveyancing search?
No. Your solicitor’s searches cover title, local authority records and environmental matters. This report answers a different question: what you could build.
How fast can you turn it round?
Messages before 3pm get a reply the same working day, and we confirm the delivery time when you order, with offers in mind.
Find out what the house will let you build
Send the address and the project you have in mind. We send the report for £185.