Key legal question
Whether the cantonal authorities arbitrarily applied setback-distance rules by treating the existing house and annex as one building unit and applying only the small setback distance.
Extracted holding
The authorities' assessment was defensible and not manifestly untenable; no arbitrariness was shown in the interpretation and application of cantonal setback rules.
Extracted reasoning
Section 17(2) ABauV/AG leaves the relevant facade to be determined by the local circumstances. The authorities could reasonably consider the existing house and planned annex as a single unit and focus on the southwest facade as the main residential side. Competing interpretations existed, but the chosen one was not obviously wrong.