Deck Term Glossary
Baluster: One of a series of vertical supports used between posts of a railing. Also called a spindle.
Building Codes: Regulations detailing accepted materials and methods of building, such as the size of the deck, setback distances, railing and stair construction, footing depths, fastening methods, lumber types for certain deck components and fence or screen height around the deck. Usually adopted by city, county, or state building departments; most counties have local building codes.
Cantilever: A construction method that involves extending the joists beyond the support beam or the support beam beyond the posts.
Cap Rail: The top horizontal piece of a railing, usually placed to give it a finished appearance.
Composite Decking: Deck boards manufactured from wood fiber and plastic to form a profile which requires less maintenance and generally has a longer lifespan than natural wood.
Concentrated Load: The application of a relatively large force on a relatively small area.
Dead Load: The weight of the structure itself, which includes the plank system, support structure and any railings, built-in benches and other permanent features.
Expansion and Contraction: Boards expand when they heat up and contract when they cool down. Must be accounted for when spacing deck boards.
Fascia: The boards used to cover rim joists and end joists. Also called “skirt”.
Fasteners: Generic term for nails, bolts, screws and other connecting devices.
Footing: The below-ground support of a deck’s post, usually made from concrete.
Grade: A designation given to lumber indicating the amount of flaws and knots typically found in the wood.
Example: construction common (aka con-common) is a grade of redwood containing sapwood; construction-heart (con-heart) contains virtually no knots or blemishes.
May also refer to the gradient of a slope of a piece of land or other surface.
Inset: An area of a deck that has been cut out to accommodate decorative and landscape elements such as trees and firepits.
Joist: Horizontal framing member that support decking.
Joist Hanger: A pre-manufactured metal piece typically attached to a ledger or beam to support a joist. Joist hangers should be galvanized.
Joists: a system of sub-deck structural elements located directly beneath the deck boards, commonly using 2x6 or 2x8 lumber.
Ledger: A length of board, that is horizontally attached to the side of a house and holds up one edge of a deck.
Linear Feet: The total length of required lumber. For example, three 8-foot-long 2x4s and four 6-foot-long 2x4s both would be described as 24 linear feet of 2x4s.
Live Load: The amount of weight a deck is designed to support. Most deck designs call for a live load of 60 pounds per square foot.
Low-Voltage Lighting: Commercially available lighting systems that use a transformer to reduce the needed electrical current.
Nominal Dimensions: The label given to a standard piece of lumber. For example, 2x4 is the name for a rough- cut piece of about 2x4 inches. It is then finished by planing and sometimes sanding it down to its actual dimensions (1-7/16 in. x 3-1/2 in.).
On Center: A method of measuring distance between two structural members, such as joists, where you measure from the center of one member to the center of the other. The distance between the center of each joist (commonly 16 in. or 24 in.). Joists spaced 16 in. on center are actually 14-1/2 in. apart.
Pier Block: A masonry post. Piers often serve as above-grade footings for posts and often are made of precast concrete.
Post: The vertical structural element that rests on the footing and supports the beam.
Post Anchor: A metal piece attached to or imbedded in the footing that attaches the post to the footing and keeps the post from being exposed to moisture in the ground.
Post Cap: A small piece of material (often wood) attached to the top of the post to cover the post’s wood grain and protect the post from the weather. Can be made of many materials including metal, Injection-molded plastics, even decorative glass tops for round and square posts.
Pressure Treated Wood: Wood subjected to a high pressure treatment of chemicals as a preservative.
Rise: The vertical distance from one stair tread to another.
Riser: The vertical piece between two stair steps.
Shade Structure: A structure built above decks, usually of posts and lattice, to provide a shaded area on the deck.
Span: The distance between supports.
Structural Integrity: A structure’s uncompromised ability to safely resist the required loads.
Sub-Structure: The deck construction that is located below, and supports the deck boards and railing system. Components include joists and hangers, ledgers, rim joists, beams, posts, anchors and footers.
Wind Load: The lateral pressure on a structure in pounds per square foot, due to wind blowing in any direction.