Deck Parts Actual dimension - The dimension of a board or masonry unit as measured. See Nominal dimension. Anchor - A metal device set in concrete for attaching posts to footings or piers. Backfill - To replace earth excavated during the construction process, a material other than the original earth may be used to improve the drainage or structure of the soil. Baluster - The smaller vertical members of a railing, usually spaced at regular intervals between posts. Batterboards - Temporary stake structures used for positioning layout strings. Beam - A large horizontal framing piece, usually made of 4x or doubled 2x lumber, which attaches to the posts and supports the joists. Bevel cut - An angle cut along the edge of a piece of wood. Blocking - Short pieces of lumber cut from joist material and fastened between joists for reinforcement. Bracing - Diagonal crosspieces nailed and bolted between tall posts, usually those more than 5 feet tall. Building codes - Community ordinances governing construction or modification of structures. Most codes concern fire safety and health, with separate sections relating to electrical, plumbing, and structural work. Building permit - A license authorizing specified construction work. The permit requires that the work be done in accordance with building codes and requires one or more inspections. In most municipalities, building a deck requires a building permit. Butt joint - The joint formed by square-cut ends or edges; the easiest carpentry joint, but also the weakest. Cantilever - A framing member that extends beyond a post or support, typically more than 2 feet. Cantilevers help hide some posts, giving the deck the appearance of floating. Chamfer - An angle cut along one corner of an edge, not the entire edge. Cement - A powdered mix of gypsum and other materials that serves as the binding element in contrete and mortar. Check - A crack on the surface of a board. If the check runs more than halfway through the thickness of a board, the structural integrity is diminished, and the board should not be used. Cleat - A length of board attached to strengthen or add support to a structure. Concrete - A mixture of portland cement, fine aggregate (sand), course aggregate (gravel or crushed stone), and water. Concrete becomes harder and stronger with age. Countersink - To drive the head of a nail or screw so that its top is flush with the surface of the surrounding wood. Crook - A bend along the length of a board, visible by sighting along one edge. With decking, a slight crook - no more than 3/4 inch in an 8-foot board - can be corrected with the board is fastened down. Crown - A slight edgewise bow in a board. In framing, the crown edge is placed upward so gravity will in time force it down. Cup - A curve across the widgh of a board. Unless it is sever, cupping is not a problem for framing lumber. Slight cupping in a decking board can be taken out by screwing down each side of the board. Reject any boards with cupping more than 3/4 inch deep. Decking - The boards used to make the walking surface of a deck. Decking is usually made of 2" x 6", 2" x 4", or 5/4" x 6" lumber. Elevation drawing - A drawing that shows the vertical face of a deck, emphasizing footings, posts, railings, and any built-in planters, benches, skirting or overhead structures. Fascia - Horizontal trim boards that covers the ends of deck boards and part or all of the rim joist or header joist, as well as any exposed parts of a stairway. To create contrast, apply several rows of narrower boards. Finial - An ornament attached to the top of a post or the peak of an arch. Finish - A coating, such as water repellent or paint, applied to a surface to protect it against weathering. Flashing - Bent strips of sheet metal, usually galvanized steel or aluminum, that protect lumber from water. On a deck, flashing is often used to protect the ledger and the sheating behind it. Footing - A small foundation, usually of concrete, that supports a post. See pier. Galvanized Nails - Nails dipped in molten zinc (hot-dipped galvanized) to resist corrosion; preferred over electroplated zinc nails for outdoor construction. Grade - The surface of the ground. Grading - Altering the surface of ground to permit drainage, prepare an area for construction, or generally smooth the ground near a structure. Header - A perimeter framing member that runs parallel to major beams and the ledger and to which the ends of inside joists and rim joists are attached. Joist - Horizontal framing members that support a floor or ceiling. An inside or common joist is a nonperimeter joist. Joist Hanger - A metal connector that joins a joist to a ledger or header so that their top edges are flush. Lag Screw - A screw, usually 1/4 inch in diameter or larger, with a hexagonal head that can be drive with a wrench or socket. Landscape fabric - Woven synthetic fabric that allows water and air to pass, but prevents weeds from growing. Lap joint - The joint formed when one member overlaps another. Lattice - A horizontal surface made of crisscrossed pieces of wood or vinyl. Ledger - A ledger is a horizontal piece of lumber that attaches to a house's framing and provides stability for a deck. Using a ledger instead of a beam near a house means that you have fewer post holes to dig and footings to pour. For these reasons, most decks have ledgers. Level - The condition that exists when any type of surface is at true horizontal. Also a tool used to determine level. Load - Weight and forces that a structure is designed to withstand; includes dead load (the structure itself) and live loads (occupants and furnishings, snow, wind uplift and earthquake forces. Mason's line - Twine used to lay out posts, patios, footings, and structures. Preferred because it does not stretch and sag like other string. Miter joint - The joint that is formed when two members meet that have been cut at the same angle (usually 45 degrees). Nominal dimension - The stated size of a piece of lumber, such as a 2" x 4", or a 1" x 12". The actual dimension is slightly smaller. On-center (OC) - A phrase used to designate the distance from the center of one regularly spaced framing member to the center of the next. Outside joist - A joist that is part of the perimeter framing structure, other than a ledger, of a deck. See Rim joist. Pergola - An open overhead structure designed to provide shade or to support hanging or climbing plants. Pier - A block of concrete that serves as a footing to support a post. A pier can be poured concrete or a ready-made concrete pier. See Footing. Pilot hole - A small hole drilled into a wooden member to avoid splitting the wood when driving a screw or nail. Plan-view drawing - An overhead view of a deck that shows locations of footing and framing members. Plumb - The condition that exists when a member is at true vertical. See Level. Plunge cut - A circular-saw or jigsaw cut where the blade enters the wood through the surface to avoid continuing the cut to an edge or end of a board. Post - A vertical framing piece, usually 4" x 4" or 6" x 6", that supports a beam or joist. Pressure-treated wood - Lumber or sheet goods impregnated with one of several chemical solutions to resist rot. Rafter - In deck building, a framing member that supports the uppermost material that makes up a pergola. Rail - A horizontal framing member of a railing that spans between posts to support balusters and sometimes the cap rail. Ready-mix concrete - Wet concrete that is ready to pour, transported in a truck from a concrete supplier. Reinforcing bar - Steel rods for reinforcing concrete, sometimes called rebar or rerod. Rim joist - A term sometimes used to describe an outside joist. Rise - The total vertical distance a stairway climbs. Also, the vertical distance between the topmost surface of two sequential treads. Riser - A board attached to the vertical surface of a stair stringer to cover the gap between treads and to provide additional tread support. Run - The total horizontal distance a stairway spans from the structure to finished grade level. Also the horizontal depth of a tread cut made in a stringer. Screening - Maximum opening allowed between railing members; distances vary by code. Sealant - A protective coating (usually clear) applied to wood and metal. Set-back - The minimul distance between a property line and any structure, as specified by local codes. Shim - A thin strip or wedge of wood or other material used to fill a gap between two adjoining components or to help establish level or plumb. Site plan - A map of your property, showing where the deck will be located on your yard. Skirt or skirting - Horizontal material installed around the perimeter of a deck to hide the area below the deck. Skirting can be made of common lattice panels, vertical or horizontal decking boards, or customized to match your home's design. Sleeper - Horizontal wood member laid directly on ground, patio, or roof for supporting a deck. Slope - Ground with an inclined surface, usually measured in vertical rise per horizontal distance. Span - The distance travelled by a beam, joist, or decking board between supporting structures. Spindle - A small-dimensioned baluster, usually made of metal such as aluminum. Square - The condition that exists when two surfaces are at a 90-degree angle. Stringer - A diagonal board used to support treads and risers on a stairway. Stringers are usually made of 2" x 12" boards. 3-4-5 triangle - A mathematical means of determing when a corner is square. Measure 3 feet along one side and 4 feet along the other; if the corner is square, the diagonal distance between those two points will be 5 feet. Tamper - A tool for compacting soil, sand, or other loose materials. Toenail - To drive a nail at an angle when joining a piece where face-nailing is not possible. Screws also can be driven in this manner. Tread - The horizontal face of each step in a stairway, often composed of two 2" x 6" boards. Zoning requirements - Ordinance that affect deck size or location, such as set-back limites (distance from property line to structure), lot coverage (percentage that can be covered by improvements), and the deck's size and height.