Flush Doors

Figure 4-17.-Three types of solid-core doors. doors with only atop and bottom rail, without horizontal or vertical muntins, are refereed to as “casement” or “French doors.” Storm doors are lightly constructed glazed doors. They are used in conjunction with exterior doors to improve weather resistance. Combination doors consist of interchangeable or hinged glass and screen panels. Flush Doors Flush doors are usually made up of thin sheets of veneer over a core of wood, particle board, or fiberboard. The veneer faces act as stressed-skin panels and tend to stabilize the door against warping. The face veneer may be of ungraded hardwood suitable for a plain finish or selected hardwood suitable for a natural finish. The appearance of flush doors maybe enhanced by the application of plant-on decorative panels. Both hollow-core and solid-core doors usually have solid internal rails and stiles so that hinges and other hardware may be set in solid wood. Two types of solid wood cores are widely used in flush-door construction (fig. 4-17). The first type, called a continuous-block, strip- or wood-stave core, consists of low-density wood blocks or strips that are glued together in adjacent vertical rows, with the end joints staggered. This is the most economical type of solid core. However, it is subject to excessive expansion and contraction unless it is sealed with an impervious skin, such as a plastic laminate. The second type is the stile-and-rail core, in which blocks are glued up as panels inside the stiles and rails. This type of core is highly resistant to warpage and is more dimensionally stable than the continuous-block core. In addition to the solid lumber cores, there are two types of composition solid cores. Mineral cores (see fig. 4-17) consist of inert mineral fibers bonded into rigid panels. The panels are framed within the wood rails and stiles, resulting in a core that is light in weight and little affected by moisture. Because of its low density, this type of door should not be used where sound control is important. The other type (not shown) has particleboard, flakeboard, or waferboard cores, consisting of wood chips or vegetable fibers mixed with resins or other binders, formed under heat and pressure into solid panels. This type of core requires a solid-perimeter frame. Since particleboard has no grain direction, it provides exceptional dimensional stability and freedom from warpage. Because of its low screw-holding ability, it is usually desirable to install wood blocks in the core at locations where hardware will be attached. DOORJAMBS The doorjamb is the part of the frame that fits inside the masonry opening or rough frame opening. Jambs may be wood or metal. The jamb has three parts: the two side jambs and the head jamb across the top. Exterior doorjambs have a stop as part of the jamb. The stop is the portion of the jamb that the face of the door closes against. The jamb is 1 1/4 inches thick with a 1/2-inch rabbet serving as a stop. 4-13