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 adjoining owner's (AO's) express written consent (Section 7(4)). Without that consent you must use traditional foundations — often this is the practical reason a surveyor preparing a Schedule of Condition (a written and photographic record of the neighbouring property's condition before works start) becomes involved early.
Adjoining owner response options
For this Section 3 notice, the AO may consent to the works in writing, dissent and concur in the appointment of an Agreed Surveyor (a single surveyor appointed by both owners to resolve the dispute), or dissent and appoint their own surveyor within the 14-day response window. No written consent within that period can give rise to a deemed dispute; it is not consent by silence.