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.
Indirect Gain System: a type of passive solar construction that stores solar energy/heat in structures of masonry or water vessels and then transmits the heat into living space by convection, radiation or conduction.
Inlay: a decorative technique of inserting pieces of contrasting, often coloured materials into depressions in a base object to form patterns or pictures that normally are flush with the surface. In wood, inlays commonly use wood veneers, but other materials like shells, mother-of-pearl, horn or ivory may also be used.
Insulation: refering to thermal insulation, any material whose heat transmission resistance is high enough to be placed in structures for the purpose of reducing heat loss.
Intarsia: a form of wood inlaying that is similar to marquetry. Uses varied shapes, sizes and species of wood fitted together to create an almost 3-D inlaid, mosaic-like picture
Interior Panel: plywood or other type of formed composite panel board which is not waterproof and is intended for interior use only.
Interior Trim: generic term referring to the molding, baseboard, casing and other trim items installed in a building by a finish carpenter.
In The White: The natural, unpainted surface of a piece of wood.
Isotropic: a material having identical values of a property in all directions. As opposed to anisotropic, which wood is, having different strengths along the grain vs. across it..