Tayross Associates Chartered Building Surveyors | Party Wall Rates London | Party Wall Surveyor West London | Building/Structural RICS Survey London

Understanding Party Wall Act Considerations: When Damage Occurs Beyond 3 Metres

Tuesday 8th April 2025

Yes, you’re right to be cautious — within party wall circles, the perceived wisdom is that such damage is still very much a cause for concern, even if the cracking appears more than 3 metres away from the physical works, as long as the excavations themselves are within 3 metres of the adjoining owner’s structure and meet the depth criteria set out in section 6(1) of the Party Wall etc. Act 1996.

Here are the key considerations commonly applied:

1. Distance of Damage vs. Distance of Excavation

• The critical measurement under section 6(1) is from the point of excavation to the adjoining structure, not from the excavation to the location of damage.
• Cracks appearing further than 3 metres from the excavation do not automatically rule out causation — especially in older or less stable buildings where vibrations or ground movement can affect a wider area.

2. Mechanism of Damage

• If damage (e.g. cracking) occurs after excavations have commenced, and there’s no previous record of such cracking, then from a party wall surveyor’s perspective, it is prudent to treat it as potentially notifiable works-related damage.
• The party wall surveyor must investigate the mechanism of movement. For example:

o Is there evidence of ground movement or loss of bearing?
o Is there an identifiable path of stress or displacement from the excavation?
o Could the crack be related to changes in moisture content or other disturbances linked to the excavation?

3. Burden of Proof and Reasonableness

• Under party wall procedures, the standard is not the same as in a court of law. It’s about balance of probability and professional judgement.
• The Building Owner must prove that the works did not cause the damage if challenged, especially if there is no prior photographic schedule of condition.
• Therefore, surveyors will often err on the side of caution and recommend remedial works or monitoring, even if the damage is outside the immediate footprint.

4. Monitoring and Future Risk

• If the damage is beyond 3m from the works, surveyors may recommend:

o Crack monitoring to assess whether movement continues.
o Intrusive investigation to confirm depth and extent of excavation.
o An updated Schedule of Condition for wider areas if not already captured.

5. Common Practice

• The pragmatic approach is to acknowledge the cracking as potentially related unless clear evidence shows otherwise.
• In awards or determinations, it’s common to include clauses about without prejudice repairs or joint monitoring, particularly where causation is unclear but plausible.