When a Section 3 notice applies
Section 3 deals with the most common Party Wall scenario — works to a shared wall or other party structure. You must serve a Section 3 notice if you intend to: cut into the wall (for beams, joist hangers, flashings or sockets); raise or extend its height; underpin or lower it; demolish and rebuild it; or carry out any other work that affects the integrity of a shared structure.
Statutory notice period
A Section 3 notice requires two months of notice — the longest period under the Act. Works cannot start before the two months have elapsed unless every adjoining owner has given written consent earlier.
Common scenarios
- Loft conversions inserting steel beams into the party wall.
- Chimney breast removal where the breast is part of a shared wall.
- Raising the party wall to allow a rear extension.
- Basement conversions involving underpinning.
- Demolishing and rebuilding a party fence wall.
The “special foundations” clause
Reinforced concrete foundations to a new structure beyond the party wall require the AO's express written consent (Section 7(4)). Without that consent you must use traditional foundations — often this is the practical reason a Schedule of Condition surveyor becomes involved early.
Adjoining owner response options
Within fourteen days the AO may consent to the works in writing, dissent and concur in the appointment of an Agreed Surveyor, or dissent and appoint their own surveyor. Silence at day fifteen is not consent — it is treated as a dissent.