Shrinkage properties of wood

Roofing · Wood Shingles and Shakes · printed page 11 (PDF page 12)

Book index entries

Edge Grain Wood Shingles Flat Grain Wood Shingles Heartwood Longitudinal Shrinkage in Wood Properties of Wood Radial Shrinkage of Wood Sapwood Shrinkage of Wood Tangential Shrinkage of Wood Wood Shingle – Edge Grain Flat Grain

Text in the illustration

longitudinal shrinkage minimal (0.1%)
heartwood
tangential shrinkage (most significant) up to 7%
radial shrinkage (up to 5%)
sapwood
edge grain
no.1 blue label
best quality
flat grain
flame
no.2 red label or lesser quality
more prone to cupping, curling and splitting

Generated explanation

The illustration shows a log with exposed growth rings, identifying heartwood and sapwood and the directions of wood shrinkage. Longitudinal shrinkage is labeled minimal at 0.1%, radial shrinkage up to 5%, and tangential shrinkage the most significant at up to 7%. Lines connect the log cross-section to examples of edge-grain and flat-grain wood shingles. The edge-grain example has straight, parallel grain and is labeled no.1 blue label and best quality. The flat-grain example has a flame-shaped grain pattern, is labeled no.2 red label or lesser quality, and is identified as more prone to cupping, curling, and splitting.