(See also <i>FPA 5,</i> 3184) Studies were made on water adsorption and desorption in 500X120 mm, 0.57-10.0 mm thick wood samples in a controlled climate chamber (25°C, air speed 0.12-0. 15 m/s). Samples were exposed to relative humidity varying from 30 to 70% during two-, four-, and eight-hour test cycles. In two-hour cycles, Norway spruce, oak, and beech samples adsorbed water at the rate of 5 g/m*h2*1 surface area within one hour, with a response delay of approximately fifteen minutes. In four-hour cycles, 8g were adsorbed within four hours (one hour delay). Sipo (<i>Entandrophragma utile</i>) adsorbed less water, and ramin (<i>Gonystylus bancanus</i>) approximately 50% more water than spruce etc. Adsorption depth increased with increasing length of cycle. It is concluded that wooden surfaces in buildings can have major effects on indoor climate. -- AATA