Woodworking & Lumber Glossary

The process of allowing wood to adjust to the temperature and humidity of its installation environment before being installed. Tropical hardwoods like Ipe typically need 7–14 days of acclimation on-site.

A water-based wood preservative used to pressure-treat lumber, making it resistant to rot and insects. Commonly used for deck substructure joists and beams.

Lumber that has been dried naturally by exposure to air rather than in a kiln. Air-dried hardwood typically has a moisture content of 16–18% and is preferred for outdoor applications like decking.

An additional shipping service beyond standard freight delivery, such as liftgate service, residential delivery, inside delivery, or limited-access delivery. Each accessorial typically adds to the shipping cost.

The true measured dimensions of a board after milling. For example, a nominal '1x6' board may have an actual size of 3/4" × 5-1/2". Always confirm actual dimensions when planning your project.

A bonding agent used to join wood pieces together. Common types include PVA (polyvinyl acetate), polyurethane, and epoxy. Marine-grade adhesives are recommended for outdoor hardwood applications.

The maximum distance a board or joist can safely bridge between supports without excessive deflection. Determined by species, thickness, and load requirements.

An outdoor garden structure made of wood or other materials that forms a shaded passageway. Often built with hardwood timbers and beams for durability.

The vertical posts or spindles that fill the space between the top and bottom rails of a deck railing system. They provide safety and aesthetic appeal.

A unit of lumber measurement equal to a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). Used primarily in the hardwood lumber industry for pricing and inventory.

A legal document issued by a carrier that details the type, quantity, and destination of goods being shipped. You'll receive a BOL when your lumber shipment is picked up by the freight carrier.

A warp or curve along the length of a board's face (flat side). A bowed board curves end-to-end when laid flat. Minor bowing in long hardwood boards is common and usually correctable during installation.

Where two board ends meet on a joist. Proper butt joints should always land on a joist or blocking, with a small gap (typically 1/8") between board ends for expansion.

Short pieces of joist material installed perpendicular between main joists to provide additional support, especially at board end joints and deck perimeters.

A large horizontal structural member that supports joists. Beams rest on posts and distribute the load from the deck to the foundation. Typically made from doubled or tripled pressure-treated lumber or steel.

An angled cut along the edge or end of a board, as opposed to a square (90°) cut. Used for decorative edges, mitered corners, and custom trim work.

A woodworking joint made by cutting matching slots in two pieces of wood and inserting an oval-shaped 'biscuit' (compressed wood wafer) with glue. Provides alignment and some strength.

A piece of lumber less than 2 inches in nominal thickness and 2 or more inches in nominal width. Distinguished from 'dimension lumber' which is 2" to 4" thick.

Cross bracing installed between joists in an X pattern to prevent joist rolling and distribute loads. Similar in function to blocking but uses angled members.

A measure of heat energy. Relevant to woodworking because kiln-drying requires controlled heat application to reduce moisture content in lumber.

A packaged unit of lumber banded together for shipping. Hardwood bundles typically contain boards of the same species, size, and grade. Weight varies by species — Ipe bundles are exceptionally heavy.

An abnormal growth or wart-like protrusion on a tree trunk. Burl wood has highly figured, swirling grain patterns and is valued for decorative woodworking — though not used in decking.

The thin layer of growing tissue between the bark and wood of a tree. This is where new wood cells are produced.

Small cracks or splits that develop on the surface of wood as it dries and adjusts to moisture changes. Checking is cosmetic and does not affect the structural integrity of hardwood like Ipe. It is a natural characteristic of real wood.

The highest fire resistance classification for building materials, comparable to steel and concrete. Ipe naturally achieves a Class A fire rating, making it an excellent choice for decks near fire pits or in fire-prone regions.

The highest quality lumber grade with no visible knots, splits, or defects. Also called FAS (First and Seconds) in hardwood grading.

Manufactured decking boards made from a blend of wood fibers and plastic polymers. While lower maintenance than some woods, composites typically don't match the lifespan, strength, or natural beauty of tropical hardwoods like Ipe.

A conical hole drilled into wood so a screw head can sit flush with or below the surface. Essential when face-screwing hardwood decking to avoid tripping hazards.

A warp along the edge (narrow side) of a board. A crooked board curves when viewed from the end. Distinguished from bow, which curves along the face.

The slight upward curve across the width of a board. When installing joists, the crown should face up so the weight of the decking flattens it over time.

A warp across the width of a board where the edges curve upward (or downward) relative to the center. Closer joist spacing helps minimize cupping in hardwood decking.

A tropical hardwood from South America, also known as Brazilian Teak. Cumaru is one of the hardest and most durable decking woods available, with a Janka hardness of approximately 3,540 lbf.

Saw blades and drill bits with tungsten carbide cutting edges. Carbide-tipped tools are essential for cutting and drilling dense tropical hardwoods like Ipe — standard steel bits dull quickly.

A flexible sealant used to fill gaps and joints. In decking, silicone or polyurethane caulk may be used at wall-to-deck transitions or around penetrations, but not between deck boards.

The main structural component of wood cell walls. Cellulose fibers give wood its strength. Tropical hardwoods have denser cellulose structures, contributing to their exceptional hardness.

A 45-degree angled cut on a board's edge or corner, smaller than a full bevel. Chamfers remove sharp edges and add a decorative detail to posts, balusters, and trim.

A small piece of wood fastened to a surface to serve as a support, guide, or attachment point. In decking, cleats may be used to support stair treads or secure fascia boards.

Any protective or decorative finish applied to wood, including oils, stains, sealers, and paints. For tropical hardwood, penetrating oil finishes are preferred over film-forming coatings.

A cut made across the grain (perpendicular to the length) of a board, as opposed to a rip cut which runs along the grain. Most field cuts during deck installation are cross-cuts.

The boards that form the walking surface of a deck. Decking boards are attached to the joist substructure and come in various profiles, species, and sizes.

Pre-assembled modular tiles made from hardwood strips mounted on a base, designed for easy installation on flat surfaces like patios, balconies, and rooftops.

Any imperfection in lumber that may affect its appearance, strength, or usability. Common defects include knots, checks, splits, wane, and warp. Grading standards define acceptable defect levels.

Lumber that has been cut and surfaced to standardized widths and thicknesses. Common nominal sizes include 1x4, 1x6, 5/4x6, 2x4, 2x6, etc.

A type of wood decay caused by certain fungi that break down cellulose and hemicellulose in wood, leaving it brittle and crumbly. Tropical hardwoods like Ipe are highly resistant to dry rot.

The permanent, static weight of the deck structure itself — including joists, beams, decking boards, railings, and fasteners. Distinguished from live load (people, furniture, snow).

A specialized screw designed for fastening decking boards. Features include a sharp point for self-starting, coarse threads for holding power, and a flat or trim head. Stainless steel is mandatory for tropical hardwood.

The amount a structural member (joist, beam, board) bends under load. Excessive deflection causes a 'bouncy' feeling underfoot. Thicker boards and closer joist spacing reduce deflection.

The mass per unit volume of wood, typically expressed in pounds per cubic foot (pcf). Ipe is approximately 69 pcf — nearly twice the density of pressure-treated pine (~35 pcf).

A flat-bottomed rectangular groove cut across the grain of a board. Used in cabinetry and some railing construction but rarely in standard decking.

The ability of wood to resist changes in size due to moisture fluctuations. Quartersawn boards and dense tropical hardwoods tend to be more dimensionally stable than softer, flatsawn lumber.

A loading/unloading platform at a warehouse where freight trucks back up to transfer cargo. If your delivery location has a dock, you can avoid liftgate fees.

A round wooden pin used to reinforce joints or serve as a plug to conceal screw holes. Hardwood dowels matching the decking species can be used to plug countersunk face screws.

Lumber that has been surfaced (planed) to a smooth finish. S2S means surfaced on two sides; S4S means all four sides. Most decking is sold S4S.

A slight groove or channel cut into the underside of a board near its edge. When used on stair treads or overhanging boards, it causes water to drip off rather than run back underneath.

The ability of wood to resist decay, insects, and weathering. Tropical hardwoods are classified by natural durability ratings — Ipe is rated 'Very Durable' (Class 1), the highest classification.

A board profile where all four edges are slightly rounded or eased. This is the standard/default profile for most hardwood decking and is the most common for face-screwing installation.

The exposed cross-section of wood fibers visible at the cut ends of a board. End grain absorbs moisture much faster than face grain and should always be sealed with end sealer to prevent splitting.

A wax-based or acrylic product applied to the cut ends of lumber to slow moisture loss and prevent end checking and splitting. Critical for all tropical hardwood installations.

The moisture content at which wood neither gains nor loses moisture to the surrounding air. Wood naturally seeks EMC based on local temperature and relative humidity. Acclimation brings wood to its local EMC.

The narrow side of a board — the thickness dimension. A standard 5/4x6 board has a 1"-wide edge and a 5-1/2"-wide face.

A small space (typically 1/8" to 3/16") left between decking boards to allow for natural wood expansion and contraction due to moisture changes. Also aids drainage and airflow.

Natural chemical compounds within wood (oils, resins, tannins) that give species their color, scent, and natural resistance to rot and insects. Ipe's high extractive content is a key factor in its legendary durability.

The widest surface of a board — the side you see when the board is installed as decking. Also called the 'show face.'

Installing decking by driving screws through the face (top) of the board into the joist below. Requires pre-drilling and countersinking in hardwood. The fastener heads remain visible.

The highest grade in the NHLA hardwood grading system. FAS boards are at least 6" wide and 8' long with a minimum 83.3% clear area on the worst face. Also referred to as Ultra Premium grade.

Boards attached vertically to the outer edge of the deck frame (rim joist) to conceal the substructure and give the deck a finished appearance.

Any hardware used to attach decking boards to joists. Includes stainless steel screws, hidden clips, and specialty systems. Always use stainless steel (316 marine grade recommended) with tropical hardwoods.

Shipping method using an open flatbed truck, typically for large lumber orders. Allows forklift unloading from the side and accommodates longer board lengths.

Lumber cut tangent to the growth rings, producing a cathedral or flame-like grain pattern on the face. Most standard lumber is flatsawn.

A classification system (classes 50–500) used by LTL carriers to categorize shipments based on density, stowability, handling, and liability. Lumber typically falls in class 55–65.

Outdoor boundary structures made from wood boards attached to posts and rails. Tropical hardwoods make exceptionally durable and attractive fence materials, often lasting decades longer than softwood alternatives.

The moisture content (typically around 25–30%) at which all free water has been removed from wood cell cavities but cell walls remain fully saturated. Below this point, wood begins to shrink as it dries.

The decorative pattern seen on a wood surface, created by grain, color variation, growth rings, and other natural features. Tigerwood is prized for its dramatic figured appearance.

A thin waterproof material (usually metal or membrane) installed at transitions — especially where a deck ledger meets a house wall — to prevent water infiltration behind the structure.

A concrete pad or pier poured below the frost line that supports a deck post. Footings transfer the deck's load to the ground and prevent settling or frost heaving.

A powered industrial vehicle used to lift and move heavy pallets and bundles. Having a forklift available at your delivery location avoids liftgate fees and makes unloading heavy hardwood much easier.

An international nonprofit that certifies forests and wood products meeting strict environmental, social, and economic standards. FSC-certified tropical hardwood ensures responsible, sustainable sourcing.

A tropical hardwood from South America, also called Brazilian Ash. Known for its golden-blonde color and excellent durability, with a Janka hardness of approximately 1,680 lbf.

The pattern formed by wood fibers and growth rings visible on the surface of lumber. Grain patterns vary by species, cut method, and individual board.

Freshly sawn lumber that has not been dried. Green lumber has a high moisture content (often 30%+) and must be dried before use.

The intentional spacing between installed deck boards. Proper gapping (typically 3/16" for hardwood) allows for drainage, airflow, and seasonal wood movement.

A quality classification assigned to lumber based on appearance, defects, and structural characteristics. Common tropical hardwood grades include FAS (Ultra Premium), Select and Better, and Mill Run.

A use category for wood that will be in direct contact with the ground or embedded in soil. Only pressure-treated lumber rated for ground contact should be used for posts and in-ground applications — even tropical hardwood posts benefit from ground-contact treatment.

Wood from broad-leaved (deciduous or tropical) trees. Despite the name, 'hardwood' refers to the botanical classification, not necessarily the physical hardness — though tropical hardwoods like Ipe are indeed extremely hard.

The dense, inner core of a tree trunk that no longer carries sap. Heartwood is typically darker, more durable, and more decay-resistant than sapwood. In Ipe, heartwood is the highly prized portion.

Clip or track systems that secure decking boards from the sides or bottom, leaving no visible fasteners on the deck surface. Requires pregrooved or tongue-and-groove boards.

A group of complex carbohydrates in wood cell walls that, along with cellulose and lignin, give wood its structure. Hemicellulose is more susceptible to decay than cellulose.

The amount of moisture in the air. Relative humidity directly affects wood's equilibrium moisture content — higher humidity causes wood to absorb moisture and expand; lower humidity causes it to shrink.

Decking products that combine multiple materials, such as a mineral-based core with a polymer cap. Positioned between natural wood and full-composite decking. Does not match the lifespan of tropical hardwood.

A premium tropical hardwood from Central and South America, also called Brazilian Walnut or Ironwood. Ipe is one of the densest and most durable commercially available woods, with a Janka hardness of 3,680+ lbf and a lifespan of 75+ years.

A general term for extremely dense hardwoods. Ipe is commonly called ironwood due to its exceptional density and hardness. Several unrelated species share this name.

A connection method where adjoining boards lock together mechanically, as in tongue-and-groove or deck tile systems. Provides a tight, secure joint without visible fasteners.

A building code that governs residential construction, including deck design. Specifies requirements for railing height, load capacity, stair dimensions, and structural connections.

A standardized test measuring the force (in pounds-force, lbf) required to embed a .444-inch steel ball halfway into a wood sample. Used to compare the hardness of different wood species. Ipe rates 3,680+ lbf.

A horizontal structural member in a deck's substructure that supports the decking boards. Joists are typically made from pressure-treated lumber and spaced at regular intervals (12", 16", 24", or 32" on center).

A U-shaped metal bracket used to attach joists to a ledger board or beam, providing a secure connection without relying solely on nails or screws driven at an angle (toenailing).

A self-adhesive waterproof membrane applied to the top of joists before installing decking. Protects the joist from moisture penetration at fastener holes and extends the life of the substructure.

The width of the cut made by a saw blade. When calculating material needs, account for kerf waste — typically 1/8" per cut.

Lumber dried in a controlled kiln (oven) to reduce moisture content, typically to 6–12%. Kiln-dried hardwood is preferred for interior applications and furniture. For outdoor decking, air-dried (16–18%) is standard.

A circular or oval section in lumber where a branch was attached to the tree trunk. Knots can be tight (solid) or loose (may fall out). Lower-grade lumber has more and larger knots.

A dangerous condition where a power tool (table saw, circular saw, router) forcefully throws the workpiece back toward the operator. Using sharp blades, proper technique, and safety equipment reduces kickback risk.

A board attached to the side of a house or structure that supports one end of the deck joists. Proper flashing and fastening of the ledger is critical for structural safety.

A hydraulic platform on the rear of a delivery truck used to lower heavy freight to ground level. A liftgate accessorial is required for residential deliveries where a forklift is not available.

A measurement of length only — one foot of board length regardless of width or thickness. The most common pricing unit for tropical hardwood decking.

A shipping method where your freight shares truck space with other shipments. The most common delivery method for residential hardwood orders. Typically 5–10 business day transit.

A heavy-duty, large-diameter screw with a hex head used for structural connections — such as attaching a ledger board to a house or connecting beams to posts.

A framework of crossed strips of wood forming a grid pattern. Often used for deck skirting to conceal the underside of a deck while allowing airflow.

A complex organic polymer that acts as the 'glue' binding cellulose fibers together in wood cell walls. Lignin gives wood its rigidity and is broken down by UV light, which is why exposed wood changes color.

Temporary, variable weight on a structure — including people, furniture, snow, and planters. Deck design must account for both live and dead loads per building code requirements.

A retail or wholesale facility that stocks and sells lumber and building materials. Specialty lumberyards may carry tropical hardwood species.

A tropical hardwood from South America, also known as Brazilian Redwood or Bulletwood. Deep reddish-brown color with a Janka hardness of approximately 3,190 lbf.

An economy lumber grade that includes a mix of board qualities as they come off the saw with minimal sorting. Mill Run boards may have more color variation, minor defects, and character than higher grades.

The process of shaping lumber using machines (planers, molders, routers) to create specific profiles like pregrooved, tongue-and-groove, shiplap, or rainscreen.

The amount of water in wood expressed as a percentage of the wood's oven-dry weight. Air-dried tropical hardwood is typically 16–18% MC; kiln-dried is 6–12%.

A handheld device used to measure the moisture content of wood. Pin-type meters insert two pins into the wood; pinless meters use electromagnetic signals. Essential for verifying acclimation.

An angled cut (typically 45°) at the end of a board, allowing two pieces to meet at a corner. Used for picture frames, deck border patterns, and railing transitions.

A measure of a wood species' bending strength — the maximum stress it can withstand before breaking. Higher MOR values indicate stronger wood. Ipe has an exceptionally high MOR.

A traditional woodworking joint where a protruding 'tenon' on one piece fits into a matching 'mortise' (hole) in another. Used in timber framing, railing construction, and fine woodworking.

The organization that sets grading standards for North American hardwood lumber. NHLA grades include FAS, Select and Better, and others.

The named size of lumber before it is surfaced/planed. A nominal '1x6' is actually about 3/4" × 5-1/2" after milling. A nominal '5/4x6' is about 1" × 5-1/2".

A structural post at the top, bottom, or turn of a stairway or at the corner of a railing system. Newel posts are typically larger than intermediate balusters and anchor the railing.

National Motor Freight Classification code — a standardized code assigned to commodities for shipping purposes. Lumber has specific NMFC codes used by freight carriers for rating.

A rectangular or shaped cutout in a board or structural member. Posts are often notched to receive beams, and boards may be notched to fit around posts or obstacles.

A measurement from the center of one structural member (joist, stud, etc.) to the center of the next. '16 inches on center' means 16" from the middle of one joist to the middle of the adjacent joist.

Applying a penetrating oil finish (typically UV-protective) to hardwood to maintain or enhance its natural color. Without oiling, hardwood will weather to a silver-grey patina over time.

The portion of a decking board that extends beyond the edge of the outer joist or fascia. A typical deck board overhang is 1" to 1-1/2" past the rim joist.

A chemical reaction between wood and oxygen that contributes to color change over time. In tropical hardwoods, oxidation often deepens the color initially before UV exposure causes greying.

The natural silver-grey surface color that develops on untreated hardwood exposed to sunlight and weather. Many homeowners embrace the patina look; others prefer to maintain the original brown color with UV oil.

A small-diameter hole drilled before driving a screw, preventing the wood from splitting. Always required when screwing into dense tropical hardwoods like Ipe.

A machine that shaves wood to a uniform thickness and smooth surface. S4S (Surfaced 4 Sides) lumber has been planed on all faces and edges.

Drilling a pilot hole before driving a fastener. Absolutely essential for all tropical hardwoods due to their extreme density — driving a screw without pre-drilling will snap the screw or split the wood.

A board profile with a groove (channel) machined into each edge to accept hidden fastener clips. Pregrooved boards allow for a clean deck surface with no visible screws.

Lumber infused with chemical preservatives under high pressure to resist rot, decay, and insects. Commonly used for deck substructures (joists, beams, posts) but not for the decking surface.

A tracking number assigned by a freight carrier to a shipment. Used to track your lumber delivery in transit.

The cross-sectional shape of a milled board. Common decking profiles include E4E (Eased 4 Edges), Pregrooved, Tongue & Groove, Shiplap, and Rainscreen.

A flat wooden platform used to stack and ship lumber bundles. Palletized shipments can be unloaded with a forklift. Tropical hardwood pallets can weigh 1,000–3,000+ lbs depending on species and quantity.

An outdoor structure with posts and an open-roof framework of beams and rafters, providing partial shade. Hardwood pergolas using Ipe or Cumaru last far longer than softwood alternatives.

A sticky substance produced by some tree species. While common in softwoods like pine, tropical hardwoods like Ipe contain natural oils rather than pitch.

The process of filling countersunk screw holes with small wooden plugs (dowels) of the same species. Creates a clean surface that conceals fasteners. An alternative to hidden clip systems.

A vertical structural member that supports beams and transfers loads to the foundation. Deck posts are typically 4x4 or 6x6 pressure-treated lumber set on concrete footings.

Using a high-pressure water spray to clean wood surfaces. For hardwood decking, use low pressure (under 1,200 PSI) with a fan tip to avoid damaging the wood fibers.

Lumber cut so the growth rings are roughly perpendicular (60–90°) to the face. Quartersawn boards are more dimensionally stable and less prone to cupping than flatsawn boards.

A siding profile with a channel on the back side that creates an air gap between the board and the wall, promoting ventilation and moisture drainage. Ideal for hardwood siding applications.

Lumber sold in a mix of lengths rather than a single specified length. Random-length bundles typically include a range (e.g., 4'–20') and are usually priced lower per linear foot.

A tropical hardwood from Southeast Asia with a reddish-brown color and excellent outdoor durability. Janka hardness of approximately 1,630 lbf.

The outermost joist that frames the perimeter of a deck. Fascia boards are often attached to the rim joist to give a finished look.

A step-shaped cut along the edge of a board, creating a lip. Shiplap and some siding profiles use rabbeted edges so boards overlap each other.

A safety barrier along the edge of a deck, typically required by code when the deck is 30" or more above grade. Consists of posts, top rail, bottom rail, and balusters or infill.

The percentage of moisture in the air relative to the maximum the air could hold at that temperature. RH directly affects wood's equilibrium moisture content and dimensional stability.

Lumber that has been cut again after initial sawing, typically to create thinner boards from thicker stock. Resawing exposes new grain patterns and is used to produce custom thicknesses.

A cut made along the grain (parallel to the length) of a board. Used to reduce a board's width. A table saw or track saw is the best tool for accurate rip cuts.

Lumber as it comes directly off the saw, with no planing or surfacing. Rough-sawn boards have a textured surface and are slightly oversized before being dressed to final dimensions.

A power tool that spins a shaped bit at high speed to cut profiles, grooves, and decorative edges into wood. Used in milling operations to create pregrooved and custom profiles.

Lumber that has been planed smooth on all four sides (both faces and both edges). Standard for finished decking and siding products.

The lighter-colored, outer portion of a tree trunk that actively carries water and nutrients. Sapwood is generally less durable and less rot-resistant than heartwood.

A board profile with a rabbet (step-cut) on each edge so boards overlap when installed, creating a tight, weather-resistant joint. Common for siding and ceilings.

Material installed around the base of a deck to conceal the underside and substructure. Can be made from lattice, horizontal boards, or vertical boards.

Wood from coniferous (needle-bearing, cone-producing) trees like pine, cedar, and fir. Despite the name, some softwoods are harder than some hardwoods. Common for framing and pressure-treated substructures.

The unsupported distance between structural members. For decking, this is the distance between joist centers. Thicker boards can span wider joist spacings.

The ratio of a material's density to the density of water. Ipe has a specific gravity of approximately 1.05 — meaning some pieces are denser than water and may sink.

A crack that extends through the entire thickness of a board, typically at the end. Proper end sealing and pre-drilling help prevent splitting in hardwood.

A unit of area measurement. To convert linear feet of decking to square feet, multiply the number of linear feet by the actual board width (in feet). For a 5.5"-wide board: LF × 0.458 = SF.

Screws, clips, and hardware made from stainless steel. Type 305 or 316 (marine grade) stainless is required for tropical hardwood to prevent corrosion, staining, and galvanic reaction with the wood's natural oils.

Small strips of wood placed between layers of lumber to allow air circulation during drying or acclimation. Proper stickering is essential when acclimating hardwood on-site.

Smoothing a wood surface using abrasive paper or discs. Sanding removes surface imperfections, opens wood pores for better finish absorption, and can restore weathered hardwood to like-new appearance.

A finish product that penetrates or coats wood to reduce moisture absorption. End sealers protect cut ends; deck sealers protect the entire board surface. Different from stain, which adds color.

A lumber grade above Mill Run and below FAS. Select and Better boards have good appearance with minor character marks. A popular choice that balances quality and value.

The reduction in wood dimensions as moisture content decreases below the fiber saturation point. Tropical hardwoods shrink less than many domestic species due to their density and tight grain structure.

Exterior wall cladding material. Hardwood siding profiles include shiplap, tongue-and-groove, and rainscreen — all providing exceptional weather protection and curb appeal.

Attaching a new structural member alongside an existing one to reinforce it. A damaged or undersized joist can be 'sistered' by bolting a new joist of the same size next to it.

A horizontal member laid on a flat surface (like concrete) to serve as a nailer or support base for decking. Sleeper systems allow hardwood decking over existing patios and rooftops.

The underside of a roof overhang or porch ceiling. Hardwood soffit boards (often tongue-and-groove) add warmth and character to architectural details.

A finishing product that adds color to wood while allowing the grain to show through. Oil-based stains penetrate better on dense hardwoods. Distinguished from paint, which sits on the surface.

The angled structural board that supports stair treads and risers. Stringers are typically cut from pressure-treated lumber in a sawtooth pattern.

The entire supporting framework beneath the decking boards — including footings, posts, beams, joists, blocking, and hardware. A properly built substructure is critical to deck longevity.

Practices that ensure forests and wood resources are managed responsibly for long-term environmental health. Includes legal harvesting, replanting programs, and FSC certification.

The increase in wood dimensions as it absorbs moisture. Wood swells more across the grain (width) than along the grain (length). Proper gapping between deck boards accommodates seasonal swelling.

Natural chemicals in wood that can leach out when exposed to water, causing brown or reddish staining on surrounding surfaces. Tropical hardwoods have high tannin content; staining diminishes over time.

A cost-saving shipping option where you pick up your lumber at a nearby freight terminal instead of having it delivered to your door. Can save significant money on shipping.

A tropical hardwood from South America known for its distinctive dark striping over a golden-orange background. Janka hardness of approximately 2,170 lbf.

Large-dimension lumber, typically 5" × 5" or larger, used for heavy structural applications like posts, beams, and pergolas.

A board profile where one edge has a protruding ridge (tongue) and the other has a matching slot (groove). The tongue of one board fits into the groove of the adjacent board, creating a tight, interlocking joint.

A warp where one corner of a board lifts while the diagonally opposite corner stays flat, creating a spiral effect. Significant twist can make a board unusable.

Driving a fastener at an angle through one board into another. Used when you can't drive a fastener straight through — common when attaching joists to beams without joist hangers.

The horizontal member at the top of a railing system that you grip with your hand. Building codes specify minimum height (typically 36" for residential) and graspability requirements.

The horizontal surface of a stair step that you walk on. Hardwood stair treads are often made from the same species as the decking for a unified look.

Hardwood species originating from tropical regions of Central America, South America, Africa, and Southeast Asia. Known for extreme density, natural durability, and rich coloring. Includes Ipe, Cumaru, Tigerwood, Garapa, and Massaranduba.

A penetrating oil finish containing UV inhibitors that protects wood from sun-induced greying and color loss. Must be reapplied periodically (typically annually) to maintain the wood's natural brown tones.

A material layer installed beneath flooring or decking. In rooftop deck applications, underlayment protects the waterproof membrane from damage by the decking structure.

An additional cost added to the base price for premium features — such as specific board lengths, custom profiles, kiln-drying, or special grades.

A thin slice of wood (typically 1/42" to 1/8" thick) used as a decorative facing over less expensive substrates. Not used in decking.

A board profile where a small V-shaped channel is formed where two boards meet edge-to-edge. Common in tongue-and-groove ceiling and wall paneling applications.

Chemical compounds released as gases from some finishes, stains, and sealers. Low-VOC and zero-VOC products are available for environmentally conscious projects.

The presence of bark or a missing edge on a piece of lumber, indicating the board was cut from near the outside of the log. Wane is a grading defect.

Any deviation from a flat, straight board. Types of warp include bow, crook, cup, and twist. Minor warping in long hardwood boards is normal and often correctable during installation.

The natural process where untreated wood changes color (usually to silver-grey) due to UV exposure and moisture cycling. Weathering does not affect the structural integrity of tropical hardwood.

The percentage of extra material ordered to account for cuts, defects, and fitting. A typical waste factor for deck projects is 10–15%. Complex layouts, angles, and shorter boards increase waste.

A finish that causes water to bead on the wood surface rather than being absorbed. Water repellents slow moisture uptake but don't prevent it entirely. Not a substitute for proper acclimation.

The measurement across the face of a board, perpendicular to its length. Common decking widths are 4" and 6" nominal (approximately 3-1/2" and 5-1/2" actual).

A paste-like product used to fill holes, cracks, and small defects in wood. Available in various colors to match wood species. Epoxy-based fillers are most durable for outdoor use.

Small cylindrical pieces of wood used to cover countersunk screw holes. When made from the same species as the decking, plugs blend in for a clean, fastener-free appearance.

The woody tissue in trees that transports water from the roots to the leaves. Xylem cells make up the bulk of what we call 'wood' — the denser and more tightly packed they are, the harder the wood.

The usable lumber output from a given quantity of raw material. Higher-grade lumber has better yield (fewer defects to cut around). Dense tropical hardwoods have high yield when properly graded.

Fasteners or hardware coated with zinc for corrosion resistance. NOT recommended for tropical hardwoods — the tannins in hardwood react with zinc, causing black staining. Use stainless steel instead.