| Daylight Factor (DF%) | DF is a ratio of exterior illumination to interior illumination. |
| Decay | The decomposition of wood substance by fungi. |
| Decortive Surfaces by CPA | Decorative surfaces can be broadly separated into two groups – overlays and coatings – and are applied by various techniques to panel products like particleboard, medium density fiberboard (MDF) and hardboard. Overlays include products such as foils, high pressure laminates, papers, TFM, veneers and vinyls. Coatings used as industrial decorative surfaces on composite wood substrates are available in both liquid and powder forms. The synergies that exist between composite panel substrates and the many decorative surfacing options available provide limitless design and application opportunities. Please use the information on this website and the advice of your supplier to help you specify the appropriate substrate and decorative surface to best meet the needs of your application. |
| Delamination | The separation of layers in laminated wood or plywood because of failure of the adhesive, either within the adhesive itself or at the interface between the adhesive and the adherend. |
| Delignification | Removal of part or all of the lignin from wood by chemical treatment. |
| Demolition and Land Clearing (DLC) | Demolition and land clearing. |
| Density | As usually applied to wood of normal cellular form, density is the mass per unit volume of wood substance enclosed within the boundary surfaces of a wood-plus-voids complex. It is variously expressed as pounds per cubic foot, kilograms per cubic meter, or grams per cubic centimeter at a specified moisture content. |
| Density Rules | A procedure for segregating wood according to density, based on percentage of latewood and number of growth rings per inch of radius. |
| Detention Ponds | Capture water run off and allow pollutants to drop out before release into next system. Either gravity or mechanically powered. Often dry except for major weather events. |
| Dew Point | The temperature at which a vapor begins to deposit as a liquid. Applies especially to water in the atmosphere. |
| Diagonal-Grained Wood Grain | Wood in which the annual rings are at an angle with the axis of a piece as a result of sawing at an angle with the bark of the tree or log. A form of cross-grain. |
| Diffuse-Porous Wood | Certain hardwoods in which the pores tend to be uniform in size and distribution throughout each annual ring or to decrease in size slightly and gradually toward the outer border of the ring. |
| Dimension | Lumber with a thickness from 38 mm standard (2 in. nominal) up to but not including 114 mm standard (5 in. nominal) and a width of greater than 38 mm standard (2 in. nominal). |
| Dipole-Dipole Forces | Intermolecular attraction forces between polar molecules that result when positive and negative poles of molecules are attracted to one another. |
| Dote | "Dote", "doze", and "rot" are synonymous with "decay" and are any form of decay that may be evident as either a discoloration or a softening of the wood. |
| Double Spread | Refers to application of adhesive to both adherends of a joint. |
| Dressed Size | The dimensions of lumber after being surfaced with a planing machine. The dressed size is usually 1/2 to 3/4 in. less than the nominal or rough size. A 2- by 4-in. stud, for example, actually measures about 1-1/2 by 3-1/2 in. (standard 38 by 89 mm). |
| Dry Rot | A term loosely applied to any dry, crumbly rot but especially to that which, when in an advanced stage, permits the wood to be crushed easily to a dry powder. The term is actually a misnomer for any decay, since all fungi require considerable moisture for growth. |
| Dry Strength | The strength of an adhesive joint determined immediately after drying under specified conditions or after a period of conditioning in a standard laboratory atmosphere. |
| Dry Wall | Interior covering material, such as gypsum board, hardboard, or plywood, which is applied in large sheets or panels. |
| Dry-Bulb Temperature | The temperature of air as indicated by a standard thermometer. (See Psychrometer) |
| Durability | A general term for permanence or resistance to deterioration. Frequently used to refer to the degree of resistance of a species of wood to attack by wood-destroying fungi under conditions that favor such attack. In this connection, the term "decay resistance" is more specific. As applied to bondlines, the life expectancy of the structural qualities of the adhesive under the anticipated service conditions of the structure. |