The "GPDO Part 1 (All Classes) - LDC Appeal Decisions" document has been updated to include 3 additional appeal decisions relating to householder permitted development legislation, for which the conclusions are as follows:

July 2019 - Code a01063 (appeal allowed):

• It is possible under Part 1 of the GPDO for a property to erect a structure that covers the full width (or more than half of the width) of the party wall. (*)
  [Note: The Class B extension involves building up across the full width of the party wall].
• In particular, in reaching the above conclusion, the Inspector noted the “curtilage” of the property does include the full width (or more than half of the width) of the party wall. (*)
  [Quote: “In this regard it was held in McAlpine v SSE [1995] 1 PLR 16 that a curtilage comprised three defining characteristics. Those are first; that it occupied a small area around a building, second; it was intimately associated with that building, and third; it had to be regarded as one part of an enclosure with the house concerned. The description of “curtilage” in the Technical Guidance (TG) to the GPDO is not inconsistent with the Court’s interpretation. It was also held in McAlpine that adjoining curtilages could overlap each other or that one could be surrounded by another. I consider this to be particularly relevant in looking at the party wall situation here, where both dwellings rely entirely on the party wall, since if it were removed both would suffer structural collapse. Hence, it must be that the relationship of the party wall is integrally part and parcel of each of the two dwellings curtilages in concordance with the three defining characteristics of curtilage set out by the Court. For these reasons, I find that the dormer extension would be within the curtilage of the host dwelling.”].
• This appeal decision states, or implies, that where a roof extension involves building up the flank wall(s) of the main house (e.g. a hip-to-gable roof extension, or a full-width rear dormer, etc), then it is possible for the materials used for the flank wall(s) of the roof extension to be “of a similar appearance” to either the walls or the roof of the existing house.
  [Note: This appeal decision implies (rather than states) this conclusion].

July 2019 - Code a01062 (appeal dismissed):

• [Note: To view these conclusions, please log onto the website as a member].

July 2019 - Code a01061 (appeal dismissed):

• [Note: To view these conclusions, please log onto the website as a member].

Notes:

• To view the conclusions, summaries, and decision notices for any of the above appeals, please view the "GPDO Part 1 (All Classes) - LDC Appeal Decisions" document. As a member of the Planning Jungle website, you can view the decision notices for all of the appeals on the website for no extra cost.
• Any of the above conclusions marked with a "(*)" contradict other appeal decisions. The "Reference Section" within the above document indicates how many appeals have supported and contradicted each particular conclusion.