If you’re planning to extend your property and need to excavate foundations, you may be required to serve an Adjacent Excavation Notice to your neighbour. Under Section 6 of the Party Wall Act 1996, this is a necessary step if your excavation work meets certain conditions.

When Do You Need an Adjacent Excavation Notice?

You’ll need to issue an Adjacent Excavation Notice if:

1. Excavating within 3 metres of your neighbour’s structure and lower than their foundations. To determine this, measure the horizontal distance from your excavation to the nearest structure—whether that’s a garden wall, garage, or the main house itself.

2. Excavating within 6 metres of their structure, and the excavation goes deeper than an imaginary line drawn at a 45° angle from the bottom of their foundations. This is detailed under Section 6(2) of the Party Wall Act.

When to Serve the Notice?

The notice must be served at least one month before work starts. Your neighbour has 14 days to respond. If they don’t, they are deemed to have dissented.

Soure: Everything You Need to Know About the Adjacent Excavation Notice