Repairs began Tuesday at the Bainbridge Avenue building where a father and son became trapped after the front stairs collapsed, but residents are concerned it could happen again.

Tenants of 2734 Bainbridge Ave., who are being forced to climb five flights of stairs in an adjacent building to cross a roof and enter their apartments, say the foundation of the building is flimsy and unstable.

The city?s Department of Buildings says repairs are being done as work crews use concrete to patch up the gaping hole left by the stairs? collapse.