Party Wall Survey for Rear Extensions in London
Planning a rear extension to create more space in your London home? If your project involves building up to or near a boundary, or carrying out works to a shared wall, you’ll likely need a Party Wall Survey under the Party Wall etc. Act 1996. Hourican Associates ensures your extension is fully compliant, protecting both your property and your relationship with your neighbours.
Why Rear Extensions Fall Under the Party Wall Act
Across London, many residential rear extensions trigger Party Wall procedures because they often involve work on or close to a shared boundary or wall. Under the Party Wall etc. Act 1996 , you must usually serve a valid Party Wall Notice before construction begins if your extension design includes any of the following:
- Building up to or on the boundary line (Section 1)
- Cutting into or raising a shared party wall (Section 2)
- Excavating near a neighbour’s foundations (Section 6)
If any of these apply, adjoining owners must be formally notified. Once notices are served, neighbours have 14 days to consent or dissent. If they dissent (or fail to respond), a Party Wall Award must be agreed before works can legally start. Our detailed guide When do I need a Party Wall Surveyor? explains these triggers in more detail.
At Hourican Associates, our Chartered Party Wall Surveyors in London manage the entire process — from serving compliant notices to agreeing Awards and Schedule of Condition Surveys — so your rear extension proceeds smoothly and legally.
How Our Party Wall Service for Rear Extensions Works
We handle every aspect of the Party Wall process for your extension, keeping your build on track and helping to maintain good neighbourly relations.
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Initial Consultation
We review your architect’s drawings and proposals to identify which sections of the Party Wall etc. Act apply (Section 1, 2 and/or 6) and which adjoining owners need to be served notice. -
Serving Party Wall Notices
We prepare and issue correctly drafted Party Wall Notices to all affected neighbours, ensuring they are valid, clear and compliant with the Act. We can also advise on how best to introduce the process to your neighbours to keep things amicable. -
Schedule of Condition Survey
Before works start, we undertake a detailed Schedule of Condition Survey of adjoining properties — including written notes and photographs. This provides an objective record of existing condition and is invaluable if damage is alleged later. -
Preparing the Party Wall Award
Where a neighbour dissents or is deemed to dissent, we prepare a legally binding Party Wall Award. This sets out how the rear extension works will proceed, including construction methods, access to neighbouring land, working hours, protection measures and damage/repair procedures. Where appropriate, we can act as an impartial surveyor for the building owner and advise adjoining owners on their rights. -
Post-Work Review
Once your extension is complete, we can revisit the neighbouring property to confirm whether any damage has occurred and advise on remedial works in line with the agreed Award.
Transparent Fixed Fees for Rear Extension Party Wall Surveys
Our Party Wall Surveys for rear extensions typically range from £1,100 – £1,500 + VAT, depending on the size and complexity of the property and the number of adjoining owners involved.
If your project only requires a Schedule of Condition Survey , fees usually range from £385 – £585 + VAT. All fees are agreed in advance with no hidden extras, and you can request an estimate via our online Party Wall surveyor quote form.
In most cases, the Building Owner (the person carrying out the extension works) is responsible for the reasonable Party Wall Surveyor fees — including those of the adjoining owner’s surveyor where appointed.
Why Choose Hourican Associates for Rear Extension Party Wall Surveys
Hourican Associates is a specialist Chartered Building Consultancy focused on residential Party Wall matters throughout London. We combine technical expertise with clear, practical advice to help rear extension projects progress without unnecessary delay or dispute.
- Chartered Building Consultancy regulated by RICS, CIOB and MCABE
- Members of the Faculty of Party Wall Surveyors (FPWS) and the Pyramus & Thisbe Society
- Specialists in residential extensions across all London boroughs
- Fast, impartial and legally compliant service with fixed, transparent fees
Our experience on hundreds of London extension projects means we anticipate common issues early, prevent unnecessary disputes and deliver seamless compliance with the Party Wall Act. For more background information, visit our Party Wall FAQs or read Understanding Party Wall issues and how surveyors save you thousands .
We regularly act as Party Wall Surveyors for extensions in Chelsea, Kensington, Fulham, Chiswick, Westminster and all areas across London.
Rear Extension Party Wall – Frequently Asked Questions
Yes — if your rear extension affects a shared wall, involves excavation within 3 metres of a neighbour’s structure, or builds up to or on the boundary line, you will usually need to serve a Party Wall Notice. Many single-storey and wrap-around extensions in London fall under Sections 1, 2 and/or 6 of the Party Wall etc. Act 1996 .
You must serve Party Wall Notices at least one month before excavation works and two months before structural works to a party wall or boundary begin. We recommend serving notice as early as possible to allow time for surveyor appointments, Schedule of Condition Surveys and agreement of the Party Wall Award before your planned start date.
If your neighbour does not reply in writing within 14 days, they are deemed to have dissented under the Act. A Party Wall Surveyor will then need to be appointed to represent them so that a Party Wall Award can be agreed. In many cases, we can act as an impartial surveyor to protect the adjoining owner’s rights while keeping your project moving.
The Building Owner — the person carrying out the rear extension works — is normally responsible for all reasonable Party Wall Surveyor costs. This usually includes their own surveyor’s fees and, where separate surveyors are appointed, the adjoining owner’s surveyor’s reasonable fees as well.
Yes — with your neighbour’s consent, we can act as the Agreed Surveyor for both parties, providing a fair, cost-effective and impartial solution under Section 10(1)(a) of the Act. This can simplify the process, reduce costs and still protect the rights of both the building owner and adjoining owner.