Contractors excavating the site of a planned 4-story building on 20th Street haven’t exactly been playing nice with the neighbors. Last week the DOB did a surprise inspection of 300 20th Street and found that excavation work on the property had caused a partial collapse of the rear extension of the building next door, the K&H Deli on 6th Avenue. The inspectors determined that there had been inadequate underpinning of the deli and that the backyards of two other adjacent properties had also been undermined. Luckily, no one was hurt by the partial wall collapse, and a contractor’s been brought in to repair the damage. We ran into the new contractor yesterday, and he told us the accident was sadly commonplace. I see problems like this with underpinning just about every other day, he said. People try to go the cheap route and it ends up costing them more. GMAP P*Shark DOB