Preparation for Blown-In Insulation in the Walls

Sealing

• Blown insulation is installed with a pneumatic blower that forces insulation through a tube and into the interior of the walls. Before you begin installing, you should inspect your walls for any openings, and seal them using foam insulation. Any openings in your wall may allow insulation to escape during installation and leave a gap that could allow outside air to bypass your insulation. A gap underneath the baseboard of the walls is a common place where insulation can escape during installation.

Fixtures

• Make sure the fixtures built into your wall are sealed so that blown insulation cannot interfere with their operation. Seal any fixtures in your walls, including electrical outlets, light switches, phone jacks and lights. It is especially important to prevent blown cellulose insulation from touching light fixtures and other electrical parts that generate heat to avoid creating a fire hazard and to prevent air leaks. You can seal most electrical outlets using a combination of spray foam insulation and plastic electrical boxes.

Reinforcement

• Reinforce weak areas in your walls to prevent them from collapsing under the pressure of the insulation blowing into your walls. Installing additional structural crossbeams between your wall studs and securing the drywall to them will often solve this problem. You can also lower the amount of pressure used to blow the insulation into the wall.

Blocking

• Blocking is used to control where blown insulation goes inside your walls. There are a number of areas inside your walls where you will need to restrict the flow of insulation. Inspect the top and bottom areas of your walls, and install blocks so they are not open to the attic or basement. Rigid foam insulation and wooden boards are common materials used to restrict the flow of blown insulation inside the walls.

Considerations

• Installing blown insulation releases a large number of airborne particles that settle on nearby objects. If you are performing an indoor installation in an existing home, make sure to shut down your heating, ventilation and air conditioning (HVAC) system and cover the registers and the return vent to prevent them from filling with particles of insulation. You should also cover the floor and other surfaces by using plastic sheeting.