Siding Terms

Lightweight metal siding popular from the 1940s-1970s. Durable and low-maintenance but dents easily and can oxidize over time. Still found on many Colorado homes.

Siding that has been primed (sealed) on the back side before installation. Back-priming prevents moisture absorption from behind, extending the life of the siding — especially important for wood and fiber cement.

A narrow vertical strip applied over joints between siding panels in a board-and-batten installation. Creates a distinctive vertical pattern.

A siding style using wide vertical boards with narrow battens covering the seams. Popular for farmhouse, modern, and rustic architectural styles.

Where two horizontal siding boards meet end-to-end. Butt joints must be caulked and staggered between courses to prevent water infiltration.

Flexible waterproofing material applied around flashing, penetrations, joints, seams, corners, and around windows and doors to prevent water and air infiltration. Must be compatible with materials and rated for exterior use. Must be regularly maintained and replaced as it ages.

Another name for fiber cement siding — a composite of Portland cement, sand, and cellulose fibers. See Fiber Cement Siding for full details.

A J-shaped or U-shaped trim piece that receives the edge of siding panels. Used around windows, doors, and at transitions.

Horizontal siding boards installed with each course overlapping the one below. The traditional New England siding style. Also called beveled siding or lap siding.

James Hardie's factory-applied finish process that bakes multiple coats of color onto fiber cement siding. Provides a more consistent and durable finish than field-painting, with a 15-year color warranty.

A vertical trim piece installed at inside and outside corners of the house. Receives the ends of siding courses and creates a finished corner detail.

A single horizontal row of shingles or siding across the roof or wall.

The attractiveness of a home as viewed from the street. New siding is one of the most impactful improvements for curb appeal and resale value.

When the layers of engineered wood or composite siding separate due to moisture infiltration. A common failure mode for engineered wood products.

A metal flashing installed above windows and doors to direct water away from the frame. Also called head flashing.

A siding profile where each board has a concave notch at the bottom, creating a decorative shadow line. Available in vinyl, fiber cement, and wood.

The horizontal lower edge of a roof that overhangs the exterior wall. Ice dams commonly form along the eaves. Siding terminates at or just below the eave line.

White, chalky mineral deposits that appear on masonry or cement-based surfaces when water evaporates and leaves dissolved salts behind.

Siding made from wood fibers, strands, or veneers bonded with adhesives under heat and pressure. Designed to look like natural wood with improved consistency. Brands include LP SmartSide.

The portion of a shingle or siding that is visible and exposed to weather after installation. For shingles, typically 5 to 5-5/8 inches. For siding, it is the width not overlapped by the course above.

A siding's ability to maintain its original color when exposed to UV radiation. Factory finishes (like James Hardie ColorPlus) typically fade less than field-applied paint.

The vertical board mounted along the eave edge of the roof where gutters are attached. Protects the rafter tails from weather. Siding often terminates at the fascia.

A composite material made from Portland cement, sand, and cellulose fibers. Extremely durable, fire-resistant, insect-proof, and rot-resistant. James Hardie is the leading manufacturer.

A classification indicating a material's resistance to fire. Fiber cement and metal siding are non-combustible. Vinyl siding melts but doesn't support combustion. Wood siding is combustible unless fire-treated.

Thin metal (aluminum, copper, or galvanized steel) or membrane installed at joints, transitions, penetrations, and around windows and doors to prevent water entry. Critical around chimneys, skylights, walls, valleys, vents, and where siding meets other surfaces.

Thin strips of wood or metal attached to the wall surface to create an air gap behind the siding. Promotes drainage and ventilation.

The triangular wall section between the edges of intersecting roof slopes. Often sided with a different material or pattern for architectural interest.

James Hardie's most popular lap siding product. A fiber cement plank available in smooth and wood-grain textures with ColorPlus factory finish.

James Hardie's fiber cement shingle siding product that mimics the look of cedar shakes.

James Hardie's fiber cement trim boards used around windows, doors, corners, and fascia for a complete, coordinated look.

A synthetic sheet material (like Tyvek) stapled to the exterior sheathing before siding installation. Blocks air and bulk water while allowing moisture vapor to escape from inside the wall. Critical for preventing mold and rot.

Siding with rigid foam insulation bonded to the back. Adds R-value and reduces thermal bridging through the studs. Available in vinyl, fiber cement, and engineered wood.

A J-shaped trim piece that frames the edges of siding around windows, doors, and other openings.

The world's largest manufacturer of fiber cement siding and trim products. Their products are the premium standard for siding in Colorado.

A small angled piece of flashing where a roof edge meets a wall, directing water into the gutter instead of behind the siding. Missing kickout flashing is one of the most common causes of hidden wall rot.

Horizontal siding where each course overlaps the one below. The most common siding style in America. Available in wood, fiber cement, vinyl, and engineered wood.

The interlocking system that connects vinyl siding panels to each other along the bottom edge. Allows panels to expand and contract with temperature changes.

A popular brand of engineered wood siding treated with zinc borate for insect and decay resistance.

An angled cut where two trim pieces meet at a corner, creating a clean joint without gaps.

A water-resistant membrane installed behind siding to block moisture intrusion while allowing water vapor to escape. Same as house wrap.

The perforated strip along the top of vinyl siding panels where nails are driven. Nails should not be driven tight — they must allow the panel to slide horizontally for thermal expansion.

Large flat or textured sheets installed vertically. Common in modern and contemporary designs. Available in fiber cement (HardiePanel), plywood, and composite.

Using high-pressure water to clean siding. Safe for most materials at appropriate pressure settings. Excessive pressure can damage vinyl, drive water behind siding, or strip paint.

The cross-sectional shape and style of a siding product — including the width, depth, texture, and shadow line it creates.

A measure of thermal resistance — how well a material resists heat flow. Higher R-value means better insulation. Standard siding has minimal R-value; insulated siding adds R-2 to R-5. For windows, R-value is the inverse of U-factor (e.g., U-factor 0.25 = R-value 4.0).

A siding installation method that creates a deliberate air gap between the siding and the house wrap using furring strips. Allows any water that gets behind the siding to drain and dry, preventing rot.

The process of removing old siding and installing new siding. Allows inspection and repair of sheathing, house wrap, and insulation.

A thick, textured shingle traditionally split from wood. Shake siding creates a rustic, dimensional appearance. Available in real wood, fiber cement (HardieShingle), and composite.

The structural panel (plywood or OSB) attached to the roof rafters or wall studs that provides a base for roofing or siding installation. For roofing, see Deck/Decking. For siding, it provides a nailing surface and structural bracing.

The underside of the roof overhang. Soffits typically contain ventilation openings (soffit vents) that allow outside air to enter the attic. Can be vented or solid, and are typically made of aluminum, vinyl, or fiber cement.

For roofing, a row of shingles or a purpose-made starter product installed along the eave before the first course of shingles, providing adhesive and wind uplift protection. For siding, a narrow strip installed at the bottom of the wall that locks the first panel in place and sets the correct angle.

The tendency of materials to expand when heated and contract when cooled. Vinyl siding expands significantly — up to 5/8 inch per 12-foot panel. Proper installation leaves gaps for this movement.

Boards or pieces installed around windows, doors, corners, fascia, and other transitions to create finished edges and architectural details.

DuPont's brand of house wrap. The most recognized name in the category, though many manufacturers make similar products.

A water-resistant or waterproof barrier installed on the roof deck beneath the shingles. Provides secondary weather protection if shingles are damaged or displaced. For siding, see House Wrap.

PVC (polyvinyl chloride) siding. The most affordable and widely-used siding material in the U.S. Low maintenance but can crack in cold weather, fade in UV, and melt near heat sources.

Small openings at the bottom edge of siding panels or at window and door J-channels that allow trapped water to drain out.

Natural wood boards used as siding. Beautiful but requires regular maintenance (painting/staining every 3-7 years). Can rot, split, and attract insects if not maintained.

A Z-shaped metal flashing installed at horizontal joints in panel siding (like HardiePanel) to prevent water from entering the seam.