Understanding Party Wall Section 6: A Practical Guide to the 3 Metre and 6 Metre Excavation Rules

When planning construction work close to a neighbouring property in England or Wales, it’s essential to understand your legal responsibilities under the Party Wall etc. Act 1996. One of the most commonly misunderstood parts of this legislation is Section 6, which deals specifically with excavations near adjoining buildings.

Whether you’re building an extension, basement, conservatory, or carrying out groundwork for foundations, Section 6 sets out the 3‑metre and 6‑metre rules that determine when a Party Wall Notice must be served. This guide explains these rules clearly, why they matter, and how to stay compliant helping you avoid disputes, delays, and costly legal issues.

What Is the Party Wall etc. Act 1996?

The Party Wall etc. Act 1996 is legislation designed to prevent and resolve disputes between neighbouring property owners when certain types of construction work are carried out. It applies in England and Wales and covers three main areas:

• Work directly to a party wall or party structure (Section 2)

• Construction of new walls at or astride a boundary line (Section 1)

• Excavation work close to neighbouring buildings (Section 6)

Section 6 is particularly important because excavation can affect the structural stability of nearby buildings, even if no work is carried out directly on a shared wall.

What Is Party Wall Section 6?

Section 6 of the Act relates to excavations and foundation works carried out near an adjoining owner’s building or structure. It requires the building owner to notify neighbours in advance if the proposed excavation meets certain distance and depth criteria.

The purpose of Section 6 is to ensure that neighbours are informed of potentially disruptive or risky groundworks and have the opportunity to protect their property interests before work begins.

The 3‑Metre Excavation Rule Explained

The 3‑metre rule applies when:

• You plan to excavate within 3 metres of a neighbouring building or structure, and

• Your excavation will go deeper than the bottom of the neighbour’s foundations

Most residential properties have relatively shallow foundations, especially older homes. This means that even modest excavation work, such as digging foundations for a rear extension, can trigger the 3‑metre rule.

Common projects affected by the 3‑metre rule:

• Rear or side extensions

• Conservatories

• Garage foundations

• Garden rooms

• Structural underpinning

If both distance and depth conditions are met, a Party Wall Notice under Section 6 must be served at least one month before work starts.

The 6‑Metre Excavation Rule Explained

The 6‑metre rule applies to deeper excavations and is slightly more complex. It is triggered when:

• You plan to excavate within 6 metres of a neighbouring building, and

• Your excavation intersects with a 45‑degree line drawn downward from the bottom of the neighbour’s foundations

This rule typically applies to deep foundation works, such as:

• Basement constructions

• Piled foundations

• Large structural excavations

• Multi‑storey extensions

Even if the excavation is more than 3 metres away, it can still fall under Section 6 if it is deep enough to affect the neighbouring foundations.

Why the 3m and 6m Rules Matter

Excavation works can cause:

• Ground movement

• Subsidence

• Cracking to walls

• Structural instability

The 3m and 6m rules exist to reduce these risks by ensuring proper notification, professional assessment, and where necessary protective measures before excavation begins.

Ignoring Section 6 can result in:

• Legal disputes with neighbours

• Stop‑work injunctions

• Delays to construction

• Expensive repair claims

What Is a Section 6 Party Wall Notice?

A Section 6 Notice formally informs the adjoining owner of your intention to excavate. It must include:

• The building owner’s name and address

• Details of the proposed excavation

• Plans and sectional drawings showing depth and position

• The proposed start date

The notice must be served at least one month before excavation work begins.

What Happens After the Notice Is Served?

Once a Section 6 notice is served, the adjoining owner has 14 days to respond. They can:

1. Consent to the works – allowing construction to proceed without surveyors

2. Dissent and appoint a Party Wall Surveyor

3. Request an agreed surveyor acting for both parties

If there is dissent, a Party Wall Award is prepared. This legal document sets out:

• How the work must be carried out

• Protective measures required

• Access arrangements

• A schedule of condition of the neighbour’s property

Do You Always Need a Party Wall Surveyor?

Not every project requires surveyors, but they are strongly recommended when excavation is involved. A surveyor ensures:

• Compliance with the Act

• Accurate risk assessment

• Proper documentation

• Protection for both parties

Using a professional surveyor can prevent misunderstandings and costly disputes later.

Common Misconceptions About Section 6

“My work is on my land, so the Act doesn’t apply.”

Incorrect. Section 6 applies based on distance and depth, not land ownership.

“Small extensions don’t need notices.”

Even small foundations can be deeper than neighbouring foundations, triggering the 3‑metre rule.

“Planning permission replaces the need for a Party Wall Notice.”

Planning permission and the Party Wall Act are completely separate legal requirements.

How to Check If Section 6 Applies to Your Project

To determine whether you need to serve a notice:

• Measure the distance from your excavation to neighbouring buildings

• Identify the likely depth of neighbouring foundations

• Review your proposed excavation depth

• Consult a Party Wall Surveyor for professional advice

Early assessment helps avoid delays once construction is underway.

Best Practices for Staying Compliant

• Serve notices early

• Communicate openly with neighbours

• Use clear drawings and plans

• Appoint experienced surveyors

• Follow the Party Wall Award strictly

Good preparation builds trust and reduces conflict.

Conclusion

Party Wall Section 6 plays a vital role in regulating excavation works near neighbouring properties. Understanding the 3‑metre and 6‑metre rules helps homeowners and developers plan responsibly, protect adjoining buildings, and comply with the law.

Whether you’re building a simple extension or undertaking deep excavation work, knowing when Section 6 applies and acting early can save time, money, and stress. By following the correct procedures and seeking professional advice where needed, you can ensure your project progresses smoothly while maintaining positive neighbourly relationships.

For more information you can call Express Party Wall Surveyor at 020 3633 0823 or contact us