Air is made up of water vapor combined with dry air in a way that preserves each component’s properties. Humidity is defined in a general way as the water vapor content of air. In heating, ventilation and air conditioning (HVAC), more precise terms are used; specific humidity, absolute humidity, and relative humidity.
Archives for August 2009
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.
Jack Rafter: short rafter framing between a hip rafter and the wall plate; also a hip or valley rafter and ridge board.
Jalousie: a window which consists of parallel glass, acrylic, or wooden louvers set in a frame. The louvers are locked together onto a track, so that they may be tilted open and shut in unison, like a Venetian blind, to control airflow through the window. They are usually controlled by a crank mechanism.
Jamb: the top and two sides in a window or door frame that contact the sash or door. The word “jamb” comes from the French “jambe”, meaning “leg”.
I-Beam: steel beam having a cross section with ninety degree flanges on top and bottom, resembles a letter I shape.
Ice Dam: an ice accumulation along the eave and in the gutter. Snow that melts later cannot drain properly through the ice on the eave and in the gutter, causing problemas such as leaking roof, rotting timber and stained plaster or drywall.
ID: abbreviation for Inner Diameter, the measurement of an interior hole in a work piece, as opposed to the outer diameter, for example when specifying a washer size.
Hardboard: a manufactured wood fiber panel, ranges in density from 50 to 80 lb. per cu. ft.
Header: a structural member that is horizontal supporting the load over an opening, for example over a door or window. Also known as a lintel.