Sheathing, also referred to as wall sheathing, is a layer of material that is installed on the exterior wall surface before the finishing materials, such as siding, are applied. This material is typically made of wood-based panels, plywood, oriented strand board (OSB), or foam insulation board. The primary purpose of sheathing is to provide structural support to the wall and protect it from external elements such as moisture, insects, and wind.
The Role of Sheathing in Insulation
While sheathing primarily serves as a protective layer, it can also contribute to the overall insulation of your walls. Insulation is the process of reducing heat transfer, either from outside to inside or vice versa. Traditionally, insulation is achieved through the use of materials like fiberglass, cellulose, or spray foam, which are fitted between the wall studs. However, adding sheathing can provide an additional layer of insulation to enhance the thermal performance of the walls.
Insulation Factors
To understand how sheathing can improve insulation, it is essential to consider the factors that influence insulation performance. These factors include:
- R-Value: The R-value measures the resistance of a material to heat transfer. Higher R-values indicate better insulation properties, so it’s crucial to choose sheathing materials with high R-values.
- Air Barrier: A proper air barrier is necessary to prevent air leakage through the walls, which can significantly reduce the effectiveness of insulation. Sheathing can act as an additional air barrier, improving the overall airtightness of your walls.
- Thermal Bridging: Thermal bridging occurs when heat flows through a solid material, such as wall studs, more easily than through the insulation. By adding sheathing, you can minimize thermal bridging by creating a continuous layer of insulation, reducing heat loss or gain.
Types of Sheathing Materials
There are various types of sheathing materials available in the market, each with its own insulation properties. Here are a few commonly used ones:
- Plywood: Plywood sheathing is a durable and widely used material known for its strength and stability. While it provides some insulation value, its natural composition does not make it the most effective insulating option.
- Oriented Strand Board (OSB): OSB sheathing is an engineered wood product that offers better insulation properties than plywood. It is composed of wood strands combined with adhesive resins, providing improved thermal resistance and strength.
- Foam Insulation Board: Foam insulation board is a popular sheathing material due to its excellent insulation qualities. It is typically made of extruded polystyrene (XPS) or expanded polystyrene (EPS). Foam board sheathing can significantly enhance the insulation value of your walls due to its high R-value.
Incorporating sheathing into your wall construction can certainly increase the insulation value of your walls. By choosing appropriate materials with higher R-values, you can enhance the thermal performance of your home. Additionally, sheathing can create another layer of protection, acting as an air barrier and minimizing thermal bridging. When considering sheathing options, keep in mind factors such as material type, R-value, and your specific climate to ensure the best insulation results for your walls.