A.Peggi Clouston, assistant professor of building materials and wood technology at the University of Massachusetts Amherst and a specialist in engineered wood products, material mechanics, and timber design, responds: Floor squeaks occur when the shank of a nail or staple rubs against the wood fiber surrounding it. Relative movement between the fastener and the underlayment — which can happen when someone walks across the floor — causes friction; the squeak you hear is the release of stored energy. If you can prevent the relative movement, you can prevent the squeak.
Ring-shank and spiral-shank nails are the best fasteners for this application because they are grooved to increase friction and resist withdrawal. In fact, studies at Clemson University in South Carolina have shown that these nails have as much as twice the holding capacity of smooth-shank nails and staples.
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