183. Every sanction for the erection or re-erection of a building given or deemed to have been given by the Board as hereinbefore provided shall be available for one year from the date on which it is given, and, if the building so sanctioned is not begun by the person who has obtained the sanction or some one lawfully claiming under him within that period, it shall not thereafter be begun unless the Board on application made therefor has allowed an extension of that period.