Estimativa da deteriora？？o da madeira de assoalho de prédio histórico por meio de ondas ultrass？nicas

this study aimed to detect the external degree of decay of araucaria angustifolia (bert.) o. kuntze wood used in flooring. the visual method through grades and the non-destructive method based on the propagation of ultrasound waves were applied. the comparison between the propagation velocity of ultrasonic waves on clear wood and decayed wood showed statistical difference at the 5% level. moreover, the proportion of decay wood was inversely proportional to the velocity of propagation. the samples were evaluated only on their superficial faces, therefore additional studies to assess the influence of the wood internal defects in the ultrasonic velocity are necessary.