Party Wall etc. Act 1996

6 Adjacent excavation and construction

(1) This section applies where—

(a) a building owner proposes to excavate, or excavate for and erect a building or structure, within a distance of three metres measured horizontally from any part of a building or structure of an adjoining owner; and

(b) any part of the proposed excavation, building or structure will within those three metres extend to a lower level than the level of the bottom of the foundations of the building or structure of the adjoining owner.

(2) This section also applies where—

(a) a building owner proposes to excavate, or excavate for and erect a building or structure, within a distance of six metres measured horizontally from any part of a building or structure of an adjoining owner; and

(b) any part of the proposed excavation, building or structure will within those six metres meet a plane drawn downwards in the direction of the excavation, building or structure of the building owner at an angle of forty-five degrees to the horizontal from the line formed by the intersection of the plane of the level of the bottom of the foundations of the building or structure of the adjoining owner with the plane of the external face of the external wall of the building or structure of the adjoining owner.

(3) The building owner may, and if required by the adjoining owner shall, at his own expense underpin or otherwise strengthen or safeguard the foundations of the building or structure of the adjoining owner so far as may be necessary.

(4) Where the buildings or structures of different owners are within the respective distances mentioned in subsections (1) and (2) the owners of those buildings or structures shall be deemed to be adjoining owners for the purposes of this section.

(5) In any case where this section applies the building owner shall, at least one month before beginning to excavate, or excavate for and erect a building or structure, serve on the adjoining owner a notice indicating his proposals and stating whether he proposes to underpin or otherwise strengthen or safeguard the foundations of the building or structure of the adjoining owner.

(6) The notice referred to in subsection (5) shall be accompanied by plans and sections showing—

(a) the site and depth of any excavation the building owner proposes to make;

(b) if he proposes to erect a building or structure, its site.

(7) If an owner on whom a notice referred to in subsection (5) has been served does not serve a notice indicating his consent to it within the period of fourteen days beginning with the day on which the notice referred to in subsection (5) was served, he shall be deemed to have dissented from the notice and a dispute shall be deemed to have arisen between the parties.

(8) The notice referred to in subsection (5) shall cease to have effect if the work to which the notice relates—

(a) has not begun within the period of twelve months beginning with the day on which the notice was served; and

(b) is not prosecuted with due diligence.

(9) On completion of any work executed in pursuance of this section the building owner shall if so requested by the adjoining owner supply him with particulars including plans and sections of the work.

(10) Nothing in this section shall relieve the building owner from any liability to which he would otherwise be subject for injury to any adjoining owner or any adjoining occupier by reason of work executed by him.