Quality classes, names and dimensions

Quality classes, names and dimensions

Sawn timber is categorised into the following classes based on quality properties:

Qualities
A B C D
A1 A2 A3 A4

The main qualities are A, B, C and D. A is the highest quality class and contains qualities A1 – A4 of the share of production. The B and C qualities are not divided into sub-qualities. D is the lowest quality class and its lower limit is determined verbally without detailed tabular values. All wood properties without restrictions are allowed in the D quality. Sawn timber pieces, however, must stay in one piece and the blade should come into contact with all sides.

Dimensioned sawn timber means sawn timber rough-planed to a precise measurement. Sawn timber is dimensioned by planing it from all sides at a feeding speed of 1 mm. The result of the planing is rough and the product might exhibit unplaned areas and ridges resulting from the planing process.

Planed sawn timber means all-round planed sawn timber in the shape of a rectangle. In the planing of sawn timber, at least 2 mm is planed from all sides. The surface should be smooth and there should be no sawing roughness or ridges resulting from the planing.

New kinds of products are created when wood is combined with other materials or intelligence. These include composites made of wood and plastic or structures that react to stress. New types of special solutions can be made by defibering or pulping wood. By modifying wood, it is possible to improve its properties, an example of this being thermal wood.