Dado: a slot or trench cut into the surface of a piece of wood. When viewed in cross-section, a dado has three sides. A dado is cut across, or perpendicular to, the grain and is thus differentiated from a groove which is cut with, or parallel to, the grain.
Dead Load: the weight of the permanent stationary construction elements in a building.
Deflection: in general, the degree to which a structural element is displaced under a load. In carpentry, the amount of movement away from a straight line in a floor, shelf, counter or joist caused by weight being placed on it.
Dimensional Lumber: lumber that is finished/planed and cut to standardized width and depth specified in inches. Examples of common sizes are 2×4, 2×6, and 4×4.
Dimensional Stability: the ability of a material to withstand changes in it’s dimesnional size due to temperature or moisture changes.
Door Frame: wood assembly which forms the enclosure and support for a door. Can be either exterior or interior.
Door Stop: molding attached to the faces of door frame jambs which prevent a door from swinging through.
Dormer: a structural element of a building protruding from the plane of a sloping roof surface. Used to create usable space in the roof of a building by adding headroom and usually also by enabling addition of windows. Also known as a gable dormer if the dormer has a gable roof.
Dovetail: also called dovetail joint. A joinery technique commonly used to join peices where high tensile strength is called for, for example in joining the sides of a drawer to the front. The joint is created by cutting a traingular shaped tenon in one piece and the cooresponding mortise in the other. (See illustration) Created most often with an electric router, using a jig or template. It is technically a straight forward process, but hand-cutting dovetails requires a high degree of accuracy to ensure a snug fit and so can be difficult to master. The pins and tails must fit together with no gap between them so that the joint interlocks tightly with no movement.
Drip Cap: molding that directs water away from a structure to avoid seepage under the exterior siding material, typically applied over window and exterior door frames.
Drop Siding: siding with tongue and groove or shiplap joints, typically 3.4 inch thick and machined into various patterns.
Dry Rot: the decay of timber in buildings and other wooden structures caused by certain fungi, which when the decay is in an advanced stage, permits the wood to be easily crushed by hand into a dry powder.
Drywall: also called sheetrock. Manufactured construction material made of gypsum plaster sandwiched betwwen two sheets of thin cardboard paper. See the Gypsum Wallboard Drywall Guide
Duct Tape: a vinyl, fabric-reinforced, multi-purpose pressure sensitive tape with a soft and tacky pressure sensitive adhesive. It is generally silver or black in color but many other colors and transparent tapes have recently become available. With a standard width of 1 7⁄8 inches (48 mm), duct tape was originally developed during World War II in 1942 as a water resistant sealing tape for ammunition cases.