Kerf: the width of the cut of a saw blade. On most saws the kerf is wider than the saw blade because the teeth are flared out sideways. Also refers to the area of a cut made by a saw.
Kerfing: saw cuts or grooves that are longitudinal and of varying depths, depending on the wood piece’s thinkness. Made on the unexposed surfaces of millwork to relieve stress and avoid warpage. Also used to facilitate bending wood.
Keyhole Saw: a long, narrow-bladed saw used for cutting small, often awkward features in various building materials. There are typically two varieties of keyhole saw: the fixed blade type and retractable blade type. Also called a pad saw, alligator saw, jab saw or drywall saw.
Knee Brace: a diagonal corner brace fastened between a vertical structural member and a horizontal member.
Kiln Dried: wood seasoned in a kiln, under conditions of controlled temperatures, air circulation, and humidity.
Knocked Down: unassembled structural units that require assembly after delivery to a job site.
Knot: a particular type of imperfection in a piece of wood; it will adversely affect the technical properties of the wood. A knot is an area that once formed either the base of a side branch or a dormant bud. Knots materially affect cracking (known in the industry as checking) and warping, ease in working, and cleavability of timber. They are defects which weaken timber and lower its value for structural purposes where strength is an important consideration.
Kraft Paper: a building paper that is strong and relatively coarse. Kraft paper is usually a brown colour but can be bleached to produce white paper. Used to face blanket insulation materials and as flashing around window joints.