Timber " blockhouse " is manufactured in lengths from 2000 to 6000 mm. The width of such lining is measured as the face of the usable width and thickness is the maximum thickness of the board regardless of the section are the most common sizes of the following :

20 × 90 × 2000 mm
20 × 90 × 6000 mm
30 × 140 × 2000 mm
30 × 140 × 6000 mm
36 × 190 × 2000 mm
36 × 190 × 6000 mm

Class A has a strong swirls with minor injuries , as well as sound knots , resin pockets and wormholes up to 3 mm , but no longer than 50 cm by P.

Class B involves healthy dark knots up to 45 mm, ingrown knots up to 65 mm and swirls with injuries , fractures to 1 mm thick in the amount not exceeding a quarter of the product. In addition, resin pockets and allowed wormhole width not exceeding 8 mm.