Do I Need a Party Wall Surveyor for Building a New Extension?

Thinking about building a new extension to add more living space, a bigger kitchen, or that dream open-plan setup? An extension can boost your home’s value and lifestyle—but before the builders show up, there’s a key question:

👉 Do I need a Party Wall Surveyor for building a new extension?

The short answer? Yes—if your extension affects a shared (party) wall, boundary, or your neighbour’s foundations.

In this guide, I’ll break down:

✅ When you do (and don’t) need a Party Wall Surveyor
✅ How the Party Wall Act applies to extensions
✅ How to avoid neighbour disputes
✅ Party Wall costs and how to keep them low

When Do You Need a Party Wall Surveyor for a New Extension?

The Party Wall etc. Act 1996 applies if your extension affects a shared wall, boundary, or your neighbour’s foundations.

You’ll need to serve a Party Wall Notice and possibly appoint a Party Wall Surveyor if:

🔹 You’re building up to or astride the boundary line.
🔹 The extension shares or attaches to a party wall.
🔹 You’re excavating within 3 metres of your neighbour’s foundations and going deeper than their footings.
🔹 You’re altering or demolishing a party fence wall (a wall on the boundary).

💡 Pro Tip: If your extension is built entirely on your land and away from the boundary, you likely won’t need a Party Wall Surveyor—but always double-check.

👉 Need help? Check out our Fixed Fee Party Wall Service.

Why Does the Party Wall Act Apply to Extensions?

Building a new extension can impact neighbouring properties by:

✔ Undermining foundations during excavation.
✔ Adding weight or pressure to shared walls.
✔ Causing structural movement or cracks if not done properly.

The Party Wall Act ensures that neighbours are protected, disputes are minimized, and the work is done safely.

What’s a Party Wall Notice for a New Extension?

If your extension falls under the Party Wall Act, you’ll need to serve a Party Wall Notice before starting.

Here’s how it works:

📌 Serve notice at least 2 months before starting work.
📌 Your neighbour has 14 days to respond.
📌 If they don’t reply, send a final notice (giving them another 10 days).
📌 If they object or ignore the notice, you’ll need to appoint a Party Wall Surveyor.

💡 Pro Tip: A friendly chat with your neighbour before serving notice can help smooth things over.

👉 We can help serve your Party Wall Notice hassle-free.

What Happens If My Neighbour Objects?

If your neighbour objects to the extension, here’s what happens:

1️⃣ Both parties appoint Party Wall Surveyors.
2️⃣ The surveyors draft a Party Wall Award—outlining how the extension will be built safely.
3️⃣ If surveyors can’t agree, a Third Surveyor is brought in to make the final decision.
4️⃣ Once the Party Wall Award is agreed upon, you can legally begin building.

💡 Want to save money? Get your neighbour to agree to use one Agreed Surveyor for both parties.

👉 See our Fixed Fee Party Wall options here.

What’s in a Party Wall Award for a New Extension?

A Party Wall Award protects both you and your neighbour during the extension project. It includes:

✔ Detailed plans – Showing how the extension will be built and its proximity to the boundary.
✔ Precautionary measures – To protect neighbouring properties during excavation and construction.
✔ Schedule of Condition – A “before” report of your neighbour’s property (to avoid false damage claims).
✔ Timelines & working hours – To minimize disruption.

💡 Tip: A thorough Party Wall Award can save you thousands if disputes arise later.

Do I Need Building Control Approval for a New Extension?

Yes—Building Control approval is essential for any new extension to ensure the work meets safety and structural standards.

Building Control will check:

✅ Foundations – To ensure they’re deep enough and won’t affect neighbouring properties.
✅ Structural integrity – Including walls, beams, and roof.
✅ Drainage and insulation – To meet current building regulations.

💡 Pro Tip: Building Control focuses on your property’s safety, while the Party Wall Surveyor ensures neighbouring properties aren’t affected. You may need both.

What Happens If You Skip the Party Wall Process?

Skipping the Party Wall process for your extension can lead to:

🚨 Neighbour filing for an injunction – Halting your project immediately.
💰 Being liable for any damage – Even minor cracks or movement.
⏰ Project delays & legal costs – Disputes can drag on and cost thousands.

💡 Tip: It’s quicker and cheaper to follow the Party Wall process before starting.

👉 We’ll handle the Party Wall process for you.

How Much Does a Party Wall Agreement for a New Extension Cost?

💡 Want to save money? Use an Agreed Surveyor and opt for a fixed-fee service.

👉 Check out our fixed-fee pricing here.

How to Keep Party Wall Costs Down for New Extensions

✅ Talk to your neighbour early – It can prevent disputes before they happen.
✅ Use an Agreed Surveyor – One surveyor for both parties halves the cost.
✅ Choose a fixed-fee service – No surprises or hidden costs.

👉 See our fixed-fee Party Wall services here.

Final Thoughts

Building a new extension is exciting, but if it affects a shared wall, boundary, or your neighbour’s foundations, the Party Wall Act applies.

✔ Serve a Party Wall Notice before starting.
✔ Get a Party Wall Agreement in place.
✔ Use a trusted Party Wall Surveyor to avoid costly disputes.

🚀 Ready to start building your extension?

👉 Contact Fixed Price Party Wall today—we’ll handle your Party Wall Agreement quickly and at a fixed price!