Attic & Rafter Insulation

Purpose Of Insulation

• Attic insulation is one of the simplest and most effective means to reduce your energy bills and increase the comfort level of your home. Heat naturally rises. Insulation prevents heated air from escaping your living area into the attic, and ultimately seeping out of your home. Installing attic insulation is not only cost-effective, but it also conserves energy and reduces your carbon footprint on the planet.

Types of Insulation

• Several types of insulation are commonly used in attics. Fiberglass and mineral wool insulation are available in rolls, or batts. These types of insulation are fire and water resistant and are available with or without a Kraft paper or foil vapor barrier facing. The rolls and batts are available in 15 and 23 inch widths to fit standard joist spacing. Rolls range in length from 16 to 100 feet and batts are available in a number of pre-cut lengths. Medium- and high-density fiberglass batts provide more insulation value than standard fiberglass and are commonly used for buildings with cathedral ceilings. Loose fill insulation is sold in bags and may be poured directly from the bag into the attic or blown with a machine. Loose fill insulation is frequently used in odd-shaped attics, or when access to the attic is limited. Polyurethane foam, known as SPF, is sprayed between the building frames. This type of insulation is generally used in unvented constructions.

R-Value

• R-Value is a means of measuring insulation's ability to resist heat flow. R-Value varies between types of insulation. It is a good idea to refer to the manufacturer to determine how much insulation you need to achieve a desired R-Value. The recommended R-Value for attics varies depending on several factors. Many state and local building codes have a required minimum R-Value for new constructions. However, if you live in a cold climate it may be advantageous to install additional insulation. Depending on your location, the recommended R-Value for attic insulation may vary from R30 to R60.

Rafter Vents

• Well-ventilated attics have soffit vents. These vents are designed to allow fresh air to flow between the rafters and escape through a ridge or roof vent. Inadequate airflow may lead to excessive heat and humidity in the attic and rafter areas. Rafter vents, or baffles, are installed to provide a space between the rafters and the insulation to enable proper airflow. Rafter vents are typically installed between the sloped ceiling rafters at the point where the attic ceiling meets the floor. Once the rafter vents are in place, insulation may be installed to the outer edge of the attic floor so sufficient air flow is not compromised.