This presentation discusses the air permeability of building board materials used in the airtight layer of timber structures. The laboratory test was performed of different samples: plasterboard, oriented strand board, cross laminated timber and surface coating participle board. The methodology of this laboratory test is described in the standard STN EN 12114. The significance of this work consists in determining values of air permeability of different building board materials. The plasterboard and cross laminated timber samples met requirement of air permeability q50< 0.1 m3/ (m2.h). These values were of interval 0.00005- 0.073 m3/ (m2.h). The largest value of the air permeability was observed in the oriented strand board samples of range values 0.107- 1.504 m3/ (m2.h). Regarding the lacking properties in the participle board, it might be possible to improve surface coating. The results of laboratory test indicate quality of different manufacturer building board materials. The manufacturing process is influenced by an accurate technological process.