Thu 09 Sep 2006When going down is the new going upArchitect Derek Tynan started by sinking the floor when he extended a Victorian villa in south Dublin. The result is a winner, says Emma Cullinan.Going down is the new going up, quips the owner of a south Dublin house which has just been extended by DTA Architects. When we think of extensions we do indeed think of another storey being put on top of a building, or a structure being added to the rear of a house.