Beautiful Skin, Not Too Deep
An important finishing step in building construction is to apply cladding materials as an exterior skin or facade. While these materials may improve building aesthetics they can also function to control environmental elements such as air, temperature, water, and light. Improperly selected or placed they can also become a hazard, such as stripped glass panels in high wind or falling masonry siding during earthquakes. It becomes important then to choose cladding treatments with proper consideration to function, aesthetics, cost, and environment.
Choices And Then Some
Although the available selection of specific materials is quite large they can be collected into several broad categories:
Wood: One of the most diverse materials, wood cladding may consist of natural or sawn products such as clapboards, shingles, and planks; composites such as plywoods, chipboards, and fiberboards; and veneers. Natural wood products typically are more demanding to install and maintain but can lend a more desirable appearance in certain cases. Composite wood has greater installation flexibility but typically requires a finishing layer of paint, veneer, or resin. Veneers are rarely used but can effect the look of natural, rare, and/or exotic wood while avoiding excessive consumption.
Wood products in general are considered sustainable, durable, and weather resistant. They will also require greater maintenance for appearance and resistance to damage by insects.
Masonry: Natural stone is one of the oldest types of this cladding material. There are also fired masonry products such as brick and tiles, cast materials such as stucco, concrete blocks and panels, and veneers of brick and stone. Masonry products typically have high initial material and installation costs but also comprise some of the most durable and low maintenance selections available.
Metals: Thin skins of aluminum, steel, and copper are the typical materials used for cladding. No longer limited to corrugated products there are also molded panels, shingles, trims, and of course gutters and flashing produced from these metals. While also low maintenance and durable these skins tend to be initially expensive and more vulnerable to damage from hail or wind blown projectiles.
Ceramic: One of the most visually diverse products, this category includes tiles and panels made of fired ceramic clays. Just as in pottery, various dyes, glazes, and finishes can be combined in an almost infinite display of color and patterns. Quality ceramic materials are also very durable and almost maintenance free. These properties also dictate higher material and installation costs, however, and are typically reserved for commercial buildings.
Glass: Traditionally used for windows and window walls, glass used as cladding lends a dramatic, modern look to buildings. Available as hardened glass tiles and panels but also as an even tougher laminate “sandwich" of metal, colorizing layers, and glass. Again, very durable and low maintenance but with higher material and installation costs.
Polymers: The thinnest cladding skins of all consisting of paints, spray applied coatings, and molded or extruded panels. With almost endless colorizing schemes available along with toughening fillers and additives, paints have become much more durable and versatile compared to the original whitewash. While costs have risen as a result, paint is still the most cost effective cladding available today. Slightly thicker and longer lasting are spray applied coatings such as epoxys and low VOC urethanes, although cost is higher as well. Finally, extruded or molded polymer panels are one of the most cost effective cladding materials in this category. Vinyl siding is perhaps the most well known example but others are available as well such as ABS and polycarbonate. Longer lasting and more attractive than earlier products, polymers have a good sustainability rating due to their recycling potential.
Composites: Finally, almost all the materials in the previous categories can be combined into composite products to lower weight, increase insulation ratings, and improve versatility. Exterior Insulation and Finish Systems (EIFS), insulated concrete forms, expanded foam core vinyl, laminates, and many other combinations are available as cost effective additions to the listing. Even high tech combinations are becoming available like photovoltaic panels and color changing tiles.
The Importance of Being Tenacious: Application Systems & Fasteners
Even the best cladding material becomes worth less and even dangerous if the connection system employed is not appropriate to the application. In seismic zones where buildings must be designed to flex the cladding fastening system must be able to take the excess movement as well. Hurricane and other high wind areas require applications that can withstand the extraordinary air pressure changes during these weather events. Flying panes of glass and falling concrete panels are not items the Civil Engineer wants to see on the news. Or anyone else, for that matter. But designed and installed correctly, cloaks and claddings are usually a welcome finishing touch to building construction.