Rent Restrictions Acts - Scotland The purposes of these Acts are (1) To protect the tenants of the houses to which the Acts apply (a) against increase of standard rent beyond the permitted increase and (b) against being deprived of possession and (2) To restrict the rate of mortgage interest and the calling up of mortgages on houses to which the Acts apply,, With the exceptions stated in Section 3(2) the Act of 1939 continues and extends that protection and restriction to all dwelling houses, whether built, building or to be built, the rate able value of which on the appropriate day (16th May, 1939 or the day on which the dwelling house was first assessed) did not exceed £90.