Section 45 – Rights of Owners of adjoining lands where junction line not built on
London Building Act (Amendment) Act 1939
(1) Where lands of different owners adjoin and are not built on at the line of junction or are built on at the line of junction only to the extent of a boundary wall (not being a party fence wall the external wall not built on and either owner is about to build on any part of the line of junction the following provisions shall have effect:
(a) If the building owner desires to build on the line of junction a party wall or party fence wall:
(i) the building owner shall serve notice of his desire on the adjoining owner describing the intended wall;
(ii) if the adjoining owner consents in writing to the building of party wall or party fence wall the wall shall be built half on the land of each of the two owners or in such other position as may be agreed between the two owners and the expense of building the wall shall be from time to time defrayed by the two owners in due proportion regard being had to the use made or to be made of the wall by the two owners respectively and to the cost of labour and materials prevailing at the time when that use is made by each owner respectively;
(iii) if the adjoining owner does not consent in writing to the building of a party wall or party fence wall the building owner shall not build the wall otherwise than at his own expense and as an external wall or a fence wall as the case may be placed wholly on his own land;
(b) If the building owner desires to build on the line of junction a wall placed wholly on his own land he shall serve notice of his desire on the adjoining owner describing the intended wall;
(c) Where in either of the cases described in paragraphs (a) and (b) of this subsection the building owner builds a wall on his own land he shall have a right at his own expense at any time after the expiration of one month but not exceeding six months from the service of the notice to place on land of the adjoining owner below the level of such land any projecting footings and foundation making compensation to the adjoining owner or the adjoining occupier or both of them for any damage occasioned thereby the amount of the compensation in the event of difference to be determined in the manner provided in this Part of this act.
(2) Nothing in this section shall authorise the building owner to place special foundations on land of the adjoining owner without his previous consent in writing.