Building Systems

• Softwood, predominatly evergreens, cone-bearing trees, pines, firs, hemlocks
• Hardwood, broad-leaf, flowering trees, cherry, maple, oak

• Non-homogeneous organic material
• High shrinkage and swelling across grain
• Low shrinkage and swelling along grain

Cut similar to meat, parallel layers, least expensive, tends to twist and cup, varied grain

Wood is cut at right angles, most expensive, uniform grain

• Knots – hard nodes of branches
• Checks – splits across the annual rings
• Shanks – splits between annual rings
• Pitch pockets – well-defined openings between annual rings containing solid or liquid pitch
• Wane – presence of bark or absence of wood along edge
• Cupping – curvature across face
• Crook (Crown) – curvature along edge
• Bow – curvature along length
• Twist – edges turning in opposite direction

• Board - less than 2" thick and more than 2" wide (siding, interior trim)
• Dimensional lumber - 2"-4" thick and more than 2" wide
• Timber - 5" and more in the least direction (beams, posts)