Tzara’as of houses
According to Chasidic thought, tzara’as has an extremely sublime spiritual source, which was “misdirected” and “fell down” to become the most severe of all types of ritual impurity. This idea is expressed most poignantly by the case of tzara’as of houses. For when the Jewish people destroyed their houses only to find hoards of Amorite gold, they had a clear, visible indication that there is a great degree of goodness “locked up” in the affliction of tzara’as.
And this is the inner reason why the laws of the tzara’as of houses are recorded in a section unto themselves (unlike the laws of contamination and purification of tzara’as of skin and clothes which are interwoven together). For since the tzara’as of houses openly reveals a deeper, inner good, it is utterly unique.
(Based on Likutei Sichos vol. 27, p. 107ff.)