78. Unusual covenants.

A covenant or proviso which tends to abridge or qualify the estate vested by the lease in the tenant is not one that can be inserted as a usual covenant1; and on this ground it has been held that a covenant against assigning or underletting without consent2, and a proviso for re-entry on bankruptcy3 or on breach of covenant generally4, are not usual covenants.

The following covenants and provisos have also been held to be unusual5:

  1.  

    (1)     a covenant by the tenant to rebuild and repair