Firstly, when buying a beam, it needs to be checked for the evenness of the walls, unless of course a four -dancing beam of a square section is purchased. Simply put, before buying, you need to check the correctness of the forms of the material. Secondly, it is necessary to inspect the beam for knots. Knots are quite acceptable, but only in a small amount. The presence of rotten places and cracks is much more important.