The lease specified that a building of at least twenty-five stories had to be erected on the site of the Mills Building, by May 1, 1928.

The lease had specified that the landlord was not required to compensate the tenant for these improvements.

A. "There is no automatic entitlement to a lease renewal for a nonregulated tenant unless the lease specifies otherwise," said Daniel J. Curtin Jr., a Manhattan real estate lawyer.

"A well-written proprietary lease will specify exactly what responsibility the co-op has," she said.

Floyd Hall's 40-year lease with the university specifies that the company will be held responsible for any taxes on improvements, but up to August no taxes had been assessed.

Mr. Betesh did an audit for one client who rented space in a building that was not yet completed, and whose lease specified he would pay 50 percent of operating expenses over $500,000.

If neither is negligent and the leak was the result of normal wear and tear, then the proprietary lease will specify who is responsible.

In many cases the lease will specify the procedure-usually requiring written notice to the Landlord 30, 60, or 90 days before the lease is to be terminated.

If the lease simply provides that the board can impose a late charge but does not specify the amount then the board would have the right to increase the charge.

Bruce Boyle, who manages Liberty Landing, said the lease does not specify who can use Water Taxi or when.