A sandwich core is a type of composite building material used to construct buildings, boats, and other vessels. It resembles a sheet of drywall or plywood in both shape and size, but consists of an inner core sandwiched between two exterior layers. The exterior surface of the material may consist of things like wood or cement, while the inner layer typically includes some form of insulation. Sheets may vary in thickness, depending on material and how the sheets are used.
Sandwich core construction offers many of the same advantages of building with steel I-beams. The core of the sandwich board serves as the web of the beam, which connects the two flanges, or exterior layers, to one another. Just as with steel I-beams, sandwich cores provide strength and support over many different angles. They are very rigid and durable, and able to resist forces from many directions.
The cores used in a sandwich core board may include a variety of materials, depending on application. Foam and fiberglass are among the most common core materials, though specialty insulation products can be used to add strength and thermal resistance. Plywood and fiber cement serve as popular skin materials, while more advanced projects may require the use of carbon or graphite.
Builders may use a sandwich core to form the basic structure of a home or building. These boards can be used to construct floors, walls, and ceilings in place of traditional wood or metal framing. Sandwich core products also serve as popular materials for marine vessel construction, as well as airplanes and space craft.
Sandwich core materials offer excellent strength-to-weight ratios, especially when compared to other heavy-duty materials like steel or stone. They also serve as an effective source of insulation to maintain the desired temperature. Compared to steel or concrete, sandwich cores offer a high level of flexibility to accommodate natural movement over time. They also provide a high degree of design flexibility, and can be formed into almost any shape or design.
One potential drawback to sandwich core construction is the high cost of these materials. This issue is particularly problematic for high-end sandwich core materials, such as those made from graphite or epoxy. These products also pose some limitations in terms of fire-resistance and temperature range. Both the skin materials and the cores are unlikely to slow the spread of fire during an emergency, and must be treated or covered with protective materials in many applications.