I have a restaurant with a deflection problem on the first floor. The kitchen is 15 wide and is supported with 2x12 joists that are pocketed into cinder block walls. Over the past 3 months that the restaurant has been open the grout and tile is coming loose on the floor due to the deflection of the floor.
I do have access to the floor in the basement.
I am thinking about adding new posts under the floor to stabalize the middle. Any thoughts