Taking the Bounce Out of Floors and Beams

Half joking, people often ask of the architect or structural engineer, “Will the building fall down?” Well, when considering light-frame buildings, I can confidently answer, No! Such buildings almost never fall down. But they often have problems with sagging beams or floors: They don’t break, but they might bend too much. This bending is called deflection. A common example is an overly bouncy floor. You walk across this floor, and the dishes on the table rattle. The candles flicker and the TV changes channel. You really never will fall through the floor, but you might think that you will. Most important, you just don’t feel good in this room. Deflection Defects Deflection becomes a real problem when the building is