How To Retrofit Cellulose Insulation

Retrofitting cellulose insulation, which is made from recycled newspaper treated with fire retardants, is an effective way to improve your home’s energy efficiency and comfort. You can easily install this eco-friendly insulation in existing walls without major renovations. In the video above, This Old House general contractor Tom Silva demonstrates the process of retrofitting cellulose insulation, illustrating how this simple upgrade can significantly boost your home’s thermal performance.

Preparing for Installation of Cellulose Insulation

Before beginning your retrofit, gather the necessary tools and materials and familiarize yourself with the appropriate safety precautions.

Tools and Materials Needed

You’ll need the following tools and materials for your cellulose insulation retrofit:

• 4D galvanized finishing nails
• Caulk gun
• Cellulose insulation
• Drill/driver with a 1 1/8-inch spade bit
• Hammer
• Insulation blower (you can rent one)
• Ladder
• Silicone caulk
• Tape measure
• Utility knife

Safety Precautions

When working with cellulose insulation, prioritize safety by taking the following precautions:

• Maintain proper ventilation in the work area.
• Turn off power to any electrical outlets or switches in the work zone.
• Use safety goggles to protect your eyes.
• Wear a dust mask or respirator.
• Wear gloves to avoid skin irritation.

Step-by-Step Cellulose Installation Process

Once you’ve prepared your workspace and located the necessary tools and materials, you can get started on the installation process. Follow these steps:

1. Locate two adjacent wall studs on an exterior wall.
2. Remove a shingle from the bottom of the wall between the studs using a utility knife.
3. Use a 1 1/8-inch bit to drill a hole through the wall sheathing where you removed the shingle.
4. Check for studs using a straightened wire coat hanger.
5. Remove a shingle at the top of the wall and drill another hole into the stud bay using your 1 1/8-inch bit.
6. Fill the hopper on the insulation blower with cellulose insulation.
7. Insert the blower hose’s nozzle into the lower hole in the wall.
8. Turn on the blower to force insulation up into the space between the two studs.
9. Use a rag to plug the upper hole if necessary to prevent insulation from blowing out.
10. Once you hear the blower motor start to strain, turn it off and move the nozzle to the top hole.
11. Turn the blower back on and force insulation down into the wall.
12. Continue until you have completely filled the stud bay with insulation.
13. Turn off the blower.

Finishing the Installation

Once you’ve filled the wall cavities with cellulose insulation, you’ll need to properly seal and finish your work area as follows.

Sealing the Holes

Follow these steps to prevent air leaks and moisture infiltration:

1. Apply silicone caulk around the holes in the wall.
2. Caulk along the top seam of the shingle.
3. Nail the shingles back to their original spaces using 4D galvanized finishing nails.

Moving to the Next Section

Follow these steps to continue insulating the rest of the wall:

1. Measure 16 inches from the first set of holes to locate the next stud bay.
2. Repeat the process of drilling holes and filling stud bays with insulation.
3. Continue along the wall until you have insulated all the cavities.

Maximizing Insulation Effectiveness

To optimize your newly installed insulation’s performance, follow these additional steps:

• Add weatherstripping to doors and windows.
• Air seal around windows, doors, and other openings to prevent drafts.
• Install a vapor barrier if recommended for your climate zone.
• Insulate attics and crawl spaces for comprehensive home efficiency.

Maintenance and Long-Term Care of Cellulose Insulation

Cellulose insulation requires minimal upkeep, but you can perform the following maintenance tasks to extend its lifespan:

• Address any leaks or water damage promptly to prevent insulation degradation.
• Hire a professional to inspect your cellulose insulation once every few years.
• Periodically inspect your walls for signs of settling or moisture issues.

Addressing Common Issues With Retrofitting Cellulose Insulation

When retrofitting cellulose insulation, a few common issues may arise, ranging from cold spots to reduced efficiency. Here’s how to address them:

• Control moisture: Moisture can compromise cellulose insulation’s effectiveness and lead to mold growth. To prevent this, address any sources of moisture within the walls, such as leaks or condensation. Properly seal your home’s exterior and interior surfaces to keep moisture at bay.
• Create even distribution: To maximize the effectiveness of cellulose insulation, make sure to evenly distribute it within the walls. Uneven distribution can lead to cold spots and reduced efficiency. Use a reputable blower machine and follow a systematic approach to achieve an even fill.
• Fill the gaps: Although cellulose insulation is designed to stay in place, some settling may occur over time. This can create gaps and reduce the insulation’s efficiency. If you notice significant settling, add more insulation to fill the gaps and maintain the best possible thermal performance.

Additional Benefits of Cellulose Insulation

Beyond its primary insulating properties, cellulose insulation offers several additional benefits, such as the following:

• Acoustic insulation: Cellulose offers excellent acoustic insulating properties. It can help reduce noise transmission between rooms and from the outside, creating a quieter and more serene living environment.
• Environmental impact: Made from recycled materials, cellulose insulation reduces waste and minimizes the carbon footprint associated with manufacturing new insulation products. By opting for cellulose insulation, homeowners can make an eco-friendly choice that benefits the planet.
• Pest deterrence: The borates used to treat cellulose insulation improve its fire-resistant properties while also acting as a deterrent to pests. Insects and rodents are less likely to inhabit spaces filled with cellulose insulation, so it can help keep your home pest-free.