In this study, laminated lumber of pine (Pinus sylvestris L.), oak (Quercus petrea L.) and beech (Fagus orientalis L.) was investigated. For gluing one 2K-PVAc (D4) were used. The effect of the number of wood layers (three, five and seven-layer) and the influence of the change of the relative humidity were investigated. The sample preparation was carried out at 20 °C and 65 % relative humidity. The tests were taken with the conditioned samples at 20 °C and 35 %, 65 % and 95 % relative humidity. Examined parameters were the dimensional stability, the bending strength and modulus of elasticity (bending). As expected, the dimensions of the samples were reduced as a result of the lower humidity. In case of the increased humidity, the dimensions of the samples were increased. The highest detected dimensional changes were at the five-layer laminated wood samples with about 6 %, in contrast the smallest dimensional changes had the three-layer samples with only 1 %. The bending strength was increased in climate 20/35 compared with the values from the climate 20/65. Depending on the species, the increases amounted between 13 and 27 %. The modulus of elasticity increases by approximately 13 % for hardwoods and only 1 % in the case of pine. The bending strength decreases of about 18 % due to the increased relative humidity of 95 %. The modulus of elasticity was decreased with about 3 to 7 %.