- Q.Is a wood I-beam
floor bouncier than one built with dimensional lumber?
A.Wood I-beams are actually
stiffer than dimensional lumber of a comparable size. But you
have to distinguish between "bounce" and "vibration." Because
wood I-beams are lighter, they tend to vibrate more easily,
giving the floor a hollow feel. This generally won’t be a
problem if a drywall ceiling is installed below the floor. If
the floor is open below, install strapping to the bottom of the
joists on 6-foot centers to reduce the vibration.
To reduce bounce, select wood I-beams for an allowable
deflection of 1:360, not 1:240. If you are building for a
greater anticipated load than normal (a water bed, a grand
piano), go to the next deeper joist than required by the design
Another trick is to build in the china cabinet at or near a
bearing wall, rather than out in the middle of a span. Nothing
will convince a customer he has a bouncy floor more than the
crystal in an overcrowded hutch ringing like the Bells of St.