We conducted various experimental research dealing with physical characteristics and sensation in order to be able to quantitatively express appropriate hardness in terms of comfortability in residential floors. From among these, we indicated in this paper the results of studies and the production of a prototype impact source involving the impact force of the heel, which is a representative impact force generated by footsteps. Then using the impact source to measure the amount of dynamic displacement in wooden floors of old construction and in the direct-pasted wood flooring commonly used in recent multi-family housing, we quantitatively determined the dynamic spring coefficient of traditional wood-construction floor structure, which had never before been clarified, and found that, among the displacement characteristics of floor construction, there are those that depend on bending deformation, those that depend on local compression deformation, those that have both, suggesting that those displacement characteristics may have a strong effect on the intensity of footstep sensation.
