Many party wall surveyors will be familiar with the difficulties of dealing with party walls in relation to permitted development.
It is unfortunately common for planning authorities to refuse an application for a lawful development certificate where the works include the raising of a party wall on the ground that the whole of the party wall is not owned by the applicant, and therefore does not fall within the meaning of “curtilage” in the General Permitted Development Order 1995 (“the GDPO”).
However, this interpretation is incorrect.
Historically it was the case that a party wall formed a distinct, separate title from the land on either side, with the whole of the wall owned by both parties equally (see, e.g., Wiltshire v Sidford ).
However, since the enactment of s. 38 of the Law of Property Act 1925 this is no longer the case.
From 01 January 1926 ownership of all party walls (past, present and future) are severed vertically along the boundary line, with each owner owning only their part of the wall, but with the benefit of easements of support and user over the other owner’s part of the wall.
However, it does not follow that because a portion of the party wall is not owned by the applicant, it is not with the “curtilage”. This issue was considered in two planning Inspector’s decisions of note.
143 Ordnance Road, Enfield
The first is the decision of a planning Inspector in relation to 143 Ordnance Road, Enfield. In October 2000 Mr Brade applied for a certificate of lawful development for a loft conversion, which included raising the party wall, under class B of Schedule 2 to the GPDO 1995. The London Borough of Enfield refused the application, stating the raising of the party wall meant that the development was not within the curtilage of the property, and it was not therefore permitted development.
The Inspector disagreed. The Inspector considered the authorities on the meaning of “curtilage”, and in particular McAlpine v Secretary of State for the Environment  JPL B43, and found that the party wall was within the curtilage of 143 Ordnance Road. The Inspector’s full decision can be found here.
77 Platts Lane, Hampstead
In April 2009 Mr Reeves wanted to undertake a loft conversion to 77 Platts Lane that again included raising the party wall, and applied for a certificate of lawful development. The application was refused on the same grounds; that the party wall did not fall within the curtilage of the subject property. Mr Reeves appealed to the Secretary of State.
Presumably Barnet took this view because, since the decision on 143 Ordnance Road, the GPDO had been substantially amended in 2008.
However, the Inspector found that although he was not bound by the previous decision of another Inspector, there was no reason to depart from the reasoning given on 143 Ordnance Road. The Inspector’s full decision can be found here.
As considered in 77 Platts Lane, the decision of one planning Inspector does not bind a subsequent Inspector, who is free to depart from an earlier decision.
However, it seems that the view taken by Inspectors is likely to be consistent; that party walls do fall within the meaning of “curtilage” and, subject to any other test being met, the raising of them is within the permitted development provisions of the GPDO 1995.