Siding (construction)

Siding, also known as wall cladding, is the protective material attached to the exterior of a building.

Along with the roof, it serves as the primary defense against environmental elements. These elements include sun, rain, snow, heat, and cold. By shielding the structure, siding creates a more stable and comfortable environment on the interior. While masonry walls do not require siding, any wall can be sided. However, internally framed walls made of wood or steel I-beams must always be sided.

Most siding consists of smaller pieces rather than a single large sheet. This design allows for expansion and contraction caused by moisture and temperature changes. Builders use specific joinery techniques to prevent water from entering the walls. One method is clapboard, or lap siding, where planks are laid horizontally from the bottom up. In this style, the board above overlaps the board below. Another method is board and batten, which uses thin strips of wood to cover the butt joints between panels.

Some siding, like stucco, does not use joints. Stucco is a plaster-like material applied over a lattice. Because it lacks joints, stucco can eventually crack and become susceptible to water damage.

Wood is a versatile and common siding material. It can be painted or stained in any color palette. In colonial North America, Eastern white pine was the most common choice. Other options include naturally rot-resistant woods like redwood or cedar. Shingle siding, sometimes called irregular cedar "shake," was used in early New England construction. This style was later revived in the Shingle Style and Queen Anne architecture of the late 19th century. Wood siding provides minor insulation and structural properties. However, it requires maintenance every four to nine years depending on the elements. Wood is also threatened by pests like ants and termites.

Plastic siding, such as vinyl or uPVC weatherboarding, is a popular manufactured alternative. Vinyl siding is often produced in units twice as high as traditional wood clapboard. It offers unlimited color choices and styles. While newer versions resist wear better, older vinyl could fade, crack, or buckle. Vinyl is sensitive to direct heat from sources like barbecues. Some experts also note that its heat sensitivity can help fire jump between neighboring houses. Environmentally, vinyl can be recycled but cannot be burned due to the release of toxic dioxin gases.

Metal siding is frequently used for modern, industrial, or retro buildings. Corrugated galvanized steel is common for utilitarian buildings. Aluminum cladding is also popular because it is lightweight and easy to shape. Aluminum is ideal for coastal areas with high moisture and salt. This is because aluminum reacts with air to form aluminum oxide, a hard coating that prevents degradation. Steel, however, can form rust which may weaken the material. On the other hand, steel is highly dent-resistant, making it excellent for regions prone to severe storms and hail.

Modern technology has introduced insulated siding as an improvement over standard vinyl. This siding features expanded polystyrene foam, or EPS, fused to the back. This foam fills the gap between the home and the siding. This method can reduce energy use by up to 20 percent. Insulated siding typically has an R-value of 3.96, which is triple that of other exterior cladding materials. These products are often Energy Star qualified. Manufacturers state that this durable product can last more than 50 years. The foam also makes the siding more resistant to wind and dinging.

History shows the evolution of metal siding from small components to large structures. Aluminum was first used in architecture in 1884 to mount a grounding cap on the Washington Monument. By the 1920s, Alcoa used aluminum for ornamental panels on famous buildings like the Empire State Building. In 1939, an inventor named Frank Hoess patented a configuration for modern aluminum siding. He solved problems like warping and rust by using a locking joint. This joint used a small flap on each panel to create a watertight horizontal seam.

After World War II, manufacturers began distributing aluminum siding widely for residential use.