Party Wall Act - unclear interpretation of party fence wall definition?
<p>I'm looking at sections 1(1)(b) and 20 of the Party Wall Act, and they just don't make sense to me, definitionally.</p>

<h1>Problem #1: s.20 seems to provide an impossible or meaningless definition</h1>

<blockquote>
  <p><strong>s.20:</strong> “party fence wall” means a wall (not being part of a building) which stands on lands of different owners and is used or constructed to be used for separating such adjoining lands, but does not include a wall constructed on the land of one owner the artificially formed support of which projects into the land of another owner</p>
</blockquote>

<p>The phrase excluding <em>"a wall constructed on the land of one owner the artificially formed support of which projects into the land of another owner"</em> could be read ambiguously.</p>

<ul>
<li>IT EITHER MEANS: "a wall constructed <em>entirely</em> on the land of one owner (A), the artificially formed support of which projects into the land of another owner (B)";</li>
<li>OR IT MEANS: "a wall constructed <em>partly - but <strong>not</strong> entirely -</em> on the land of one owner (A), the artificially formed support of which projects into the land of another owner (B)"</li>
</ul>

<p>The problem is, <strong>both</strong> of these are problematic, whichever is chosen.</p>

<ul>
<li><p>If the first interpretation is correct, then the wall being excluded cannot ever have been a candidate party fence wall in the first place, because to even consider it as a party fence wall, the wall must stand on more than one person's land ("a party fence wall means a wall .. which stands on lands of different owners..."). <strong><em>No</em> walls will ever be excluded if the first interpretation is correct</strong>. The clause would be meaningless.</p></li>
<li><p>If the second interpretation is correct, then we have the opposite problem. If it is intended to signify a wall constructed in part but <em>not</em> entirely on (A)'s land, then basic wall construction dictates that the wall's support will <em>always</em> project into another owner (B)'s land, because walls are supported under their full width. <strong><em>Every</em> wall that could be a party fence wall will be excluded if the second interpretation is correct.</strong> The definition wouldn't cover any walls at all.</p></li>
</ul>

<p>This is a quick sketch of the 3 ways a wall could be placed and supported near a boundary:</p>

<p><a href="https://i.stack.imgur.com/hbvFN.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hbvFN.png" alt="enter image description here"></a></p>

<ul>
<li><p>Layouts #2 and #3 aren't party fence walls because the wall itself is completely within the property boundary of B, so it doesn't "stand on lands of different owners".</p></li>
<li><p>Layout #1 <em>can</em> be a party fence wall, - but only if the exclusion clause has an ineffective/nullifying interpretation: "_a wall built on <em>just one owner's land entirely/exclusively/only</em>". If that's correct then no wall that looks like layout #1 ever gets excluded, so Layout #1 will always be deemed a party fence wall. (If we had made the alternative assumption, that it means "built partly but not entirely on an owner (A)'s land" then the Layout #1 wall is clearly built partly on (A)'s land and its support clearly projects into another owner (B)'s land, so Layout #1 could never be a party fence wall. In which case nothing could.)</p></li>
</ul>

<p>What approach to reading the exclusion clause wording would allow it to have a sensible meaning, which presumably should exclude some walls but not others?</p>

<p><em>Note: I'm asking about the meaning in law of the legislative wording, rather than "what it might be believed or assumed to mean", as these could be completely different.</em></p>

<p>The phrase in question is clarifying that if the wall (excluding the support) is on one person's property, and the support crosses into another person's property, then it is not a party fence wall.</p>

<p>Why make this clarification, given that if a wall doesn't stand "on lands of different owners", it can't be a party wall anyway?</p>

<p><a href="https://books.google.co.uk/books?id=_RmoBQAAQBAJ&amp;pg=PA226&amp;lpg=PA226&amp;dq=uk%20%20%22party%20fence%20wall%22%20%22artificially%20formed%20support%22&amp;source=bl&amp;ots=C-OxfjYmOm&amp;sig=DGgM0fFKOQ6IkOCOpSIgxu_Pe_0&amp;hl=en&amp;sa=X&amp;ved=0ahUKEwiGwrPg4_PaAhWpsaQKHTkGDIAQ6AEIYjAJ#v=onepage&amp;q=uk%20%20%22party%20fence%20wall%22%20%22artificially%20formed%20support%22&amp;f=false" rel="nofollow noreferrer">Architect's Legal Handbook: The Law for Architects</a> suggests that this is because there is a different rule for walls which separate buildings, hence the need to highlight the difference (emphasis mine):</p>

<blockquote>
  <p>...rights of adjoining owners do not arise where only the foundations project on the to the adjoining land if the wall concerned is a boundary wall, not being part of a building, <strong>but they do arise if such a wall separates buildings belonging to different owners</strong>.</p>
</blockquote>

england-and-wales statutory-construction interpretation