Party walls

Party walls and protection of neighbouring properties

A contractor must carry out their own investigations with the aid of a structural engineer when necessary, to ascertain the location and condition of adjoining structures to any building work. They must properly safeguard the stability and condition of all buildings and services at risk. This also applies to the installations of public utilities and railway undertakings.

Particular measures must be undertaken to control the transmission of noise and vibration through structural elements, or the transmission of ground borne vibration which results in adverse effects, or physical damage to neighbouring property. Similarly the risks of ground movement (settlement or heave) caused by disturbance, or excavation, must be adequately addressed.

Guidance on the Act and your responsibilities

Advice to builders and residents

The Party Wall etc. Act 1996 will apply where any excavation is:

  • within 3m of a neighbouring structure and extends deeper than that structure’s foundations; or
  • within 6m of a neighbouring structure and to a depth below a line drawn down at 45o from the underside of that structure;
  • associated with the intention to underpin or carry out works to a party wall between two properties.

If any of the above criteria are met, especially where contractors are creating basements or sub-basements, they must notify adjoining owners, informing them of the nature of the works.

The adjoining owners have rights to:

  • protective measures,
  • not to be unnecessarily inconvenienced,
  • compensation for loss or damage and
  • secured expenses to cover the possibility that the redevelopment work is interrupted at a critical stage.  

An agreement between the contractor and neighbouring property owner is likely to entail the preparation of a schedule of pre-existing condition of the adjoining building supported by photographic evidence. Following completion of the redevelopment a corresponding survey of defects may be required up to two years after the opening or reoccupation of the development.

The Council is aware that certain building activities may cause cracking or dislodge features through vibration, but this too must be dealt with by a Party Wall Agreement.

Contractors should bear in mind that complaints relating to vibration and excavation in close proximity to existing structures with the possible destabilising of neighbouring foundations, can lead to considerable delays while the problems are resolved. These may arise particularly during the demolition, piling and ground work phases.

The Council of The Royal Borough is not involved in the preparation, review or monitoring of any Party Wall Agreement.

It is standard practice where party wall issues are anticipated to appoint a firm of Chartered Surveyors or Engineers to advise on the safeguarding and protection of adjoining buildings. Developers/contractors are strongly recommended to seek professional advice on the requirements of the Party Wall etc. Act and to consult fully with adjoining owners and occupiers, so that party wall issues are properly discussed and damage and unacceptable inconvenience is avoided.


Last updated: 29 November 2019