Legal or procedural basis
Section 6, including the 3-metre depth test and 6-metre 45-degree test.
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3m & 6m Excavation Notices
Assessment of foundations and excavations close to neighbouring structures under the statutory depth tests.
Service overview
What this service covers.
Extensions, basements, underpinning and deeper foundation projects.
Section 6 applies only when the statutory distance and depth tests are met. The three-metre test compares proposed excavation with the bottom of neighbouring foundations; the six-metre route also applies a 45-degree test.
When this service may be relevant
- New foundations are proposed within three metres of a neighbouring structure.
- Deep excavation may fall within six metres under the 45-degree test.
- Basement, underpinning, drainage or foundation work is close to adjoining buildings.
Who this is for
Extensions, basements, underpinning and deeper foundation projects.
How the instruction is approached
A clear route, matched to the facts.
The Act’s requirements and any boundary procedure depend on the actual documents, ownership and site relationships. These are the usual working stages.
- 01
Check the facts
Review the drawings, ownership interests, neighbouring structures and intended start date before deciding which notice route is relevant.
- 02
Prepare the documents
Describe the work accurately, attach the information required for that notice type and identify every owner who may need to be notified.
- 03
Serve and record
Serve the notice by an authorised method, retain evidence of service and track the statutory response and notice periods.
Questions about 3m & 6m Excavation Notices
Useful context before you instruct.
General information only. Advice on a particular property requires the relevant documents and facts.
01Does being within three metres automatically mean notice is required?
No. For the three-metre route, the proposed excavation must also go below the bottom of the adjoining owner’s foundations. The levels must be assessed.
02What information must accompany the notice?
The Act requires plans and sections showing the site and depth of the excavation. The adjoining owner must also be told whether underpinning or other safeguarding is proposed.
Authoritative references
Further reading
These public sources support the general explanations on this page. They do not replace advice on the facts of a particular property.
3m & 6m Excavation Notices
Request an assessment or call back.
Describe the work, notice or concern and tell us which drawings or documents you already have. You do not need to decide the statutory route before contacting the team.
Call 020 8050 0443