Carpentry, Wood Framing, and Rough Framing
Framing systems
Platform framing is the standard for wood light frame construction: floor platform, walls, then the next platform. Balloon framing continues studs past the floor line and requires fireblocking. Studs run 16 or 24 inches on center; headers over openings are sized by span and load, and jack (trimmer) studs and king studs carry the header. Cripples fill above and below openings. Sheathing provides racking resistance and the nailing base for cladding.
Lumber and engineered wood
Grade stamps show species group, grade, moisture content (S-DRY or KD), and mill. Design values adjust for moisture, temperature, and repetitive member use. Engineered lumber such as LVL, wood I-joists, and glulam is installed per the manufacturer's tables and hole charts.
Member modification
Notches at bearing ends should not exceed one-quarter of the member depth. Holes should not exceed one-third of the depth, must sit within the middle third of the depth, and are kept out of the middle third of the span. Engineered members are modified only per the manufacturer.
Traps
Confusing nominal and actual lumber sizes; installing blocking and backing after drywall; forgetting fireblocking and air sealing at top plates and penetrations; and omitting treated lumber at sill plates on concrete or near grade.
Rule of thumb: 16-inch on-center studs give 14-1/2 inches clear between them, not 16 inches - lay out framing with the actual dimension in mind.