Knots and Surface cracks
Knot finds its origin in a branch. Healthy, sticky and starred knots do not compromise the durability of the cladding. Are not allowed jumped knots (assimilated to holes).
Surface cracks may appear on Nordic spruce cladding. These are narrow surface cracks oriented along the length of the board. They mainly appear during the drying process or in dry weather. They then, partially close again in wet or rainy weather.