There are 12 months in Hindu Calender(refer). Vastu Purusha vision will change on every three months.

According to his movements, Its good to construct west and south facing houses in Bhadrapada, Aiswija and Karthika masam.
In Margasira, Pushya and Magha masams, constructing North and west facing house are recommended.
In Phalguna, Chaitra, Vaishaka masams, constructing North and East facing houses are recommended.
In Jyesta, Ashada and shravana masams, constructing East and south facing houses are recommended.

Please note that, the above rules are applicable to main door directions of house only, not a plot. For example, In north facing plot constructing east facing house is recommend in halguna, Chaitra, Vaishaka,Jyesta, Ashada and shravana masams.