How To Fix It

Do I Need To Remove Old Attic Insulation Before Installing New?

Indoor heat redistribution is essential for maintaining a comfortable home. One way to do this is by ensuring your attic insulation is up to par. However, like everything attic insulation wears out with time and will need a replacement for optimum operation.

You need to remove old attic insulation before installing new to prevent mold and mildew accumulation which can cause serious health problems. Additionally, old insulation can compress over time, losing its ability to regulate indoor temperatures properly.

In the rest of this article, I’ll discuss why you need to remove old attic insulation before installing new. I’ll also take you through the essential considerations when removing old attic insulation and how to know when you need to install new attic insulation. Keep reading!

Why You Should Remove Old Attic Insulation Before Installing a New One?

Attic insulation is an essential home heat redistribution tool if you don’t have an attic fan. However, it’s your responsibility to maintain this insulation and keep it working properly. One way to ensure the insulation serves your home better is by replacing it when it wears out.

Expert contractors recommend removing old attic insulation before installing new for the following reasons:

Read: Ductwork Insulation: Everything You Need To Know

Prevent Mildew and Mold Growth

Installing new attic insulation on top of the old insulation creates the perfect environment for mold and mildew. These fungi thrive in moist, humid conditions. The old insulation will absorb and preserve moisture expelled by the new insulation, providing an ideal space for mold and mildew to grow.

According to the State of Rhode Island Department of Health, mold causes the following health issues:

  • Respiratory problems
  • Skin irritation
  • Watery eyes
  • Runny nose
  • Coughing
  • Wheezing
  • Headache
  • Difficulty breathing

If you have young children or elderly members in your household, they’re at a higher risk of developing health complications when exposed to mold. Thus, taking precautionary measures is essential to protect them from this exposure. 

One way to do this is by removing old attic insulation before installing a new one.

Read: What Is The Major Cause Of Thermostat And Zoning Failure?

Have a Question? Ask HVAC Technician

Click here to use the chatbox to speak with one of our technicians.
No in-home service calls. No appointments.

Maintain Indoor Temperature

As I mentioned, old attic insulation can compress over time and lose its ability to regulate indoor temperatures. Double-layered insulation can trap heat in your attic, preventing it from escaping into the rest of your home.

Compression reduces the overall R-value of the insulation. The R-value determines the ability of attic insulation to resist heat flow.

Attic insulations with higher R-values perform better in regulating indoor temperatures. When you remove old attic insulation before installing new, you prevent compression, which would otherwise reduce the R-value and affect your home’s temperature regulation.

If the old insulation can’t trap heat effectively, warm air will escape through your attic during summer and enter your living space. Alternatively, cold air will seep into your home through the attic during winter.

Old Installation Can Harbor Pests

Pests love a warm, humid environment where they can hide and breed. Consequently, old attic insulation on top of new insulation provides pests with the ideal hiding spot.

These pests will damage your insulation, invade your living space, and put your family at risk of diseases. Some of the diseases these pests can transmit include:

  • Hantavirus
  • Lyme disease
  • Plague
  • Salmonellosis
  • Tularemia
  • West Nile virus

Read: Can Zone Damper System Save You Money And Is It Really Worth It?

Prevent Foul Odors

What can you expect when pests make the inner part of your attic insulation a home? Feces and urine accumulation.

This accumulation will damage the insulation and lead to a foul odor.

When you have old attic insulation on top of new, the smell from pest droppings will eventually make its way into your living space through cracks and crevices. The last thing you want is your home to smell like a pet shelter.

Removing the old insulation before installing the new one ensures there is no layer in between to harbor the pests.

Similarly, mold accumulation can also cause bad smells, especially if still water ever makes its way into the space between both insulations.

Your New Insulation Will Fit Better

The new attic insulation will fit a lot better when you remove the old one before installation.

Achieving an excellent fit for the new insulation becomes challenging if you don’t remove the old insulation first. Remember, the insulation should fit on the surface properly to create an air barrier.

An excellent insulation fit is essential because gaps and spaces will significantly reduce your attic insulation’s efficiency.

Poorly insulated attics are a leading cause of energy loss in most homes. By ensuring an excellent fit, you reduce the heat escaping from your attic, leading to energy efficiency and lower heating bills.

Read: Why Ecobee Shuts Off Before Reaching Temperature? – Troubleshooting Guide

Things to Consider When Removing Old Attic Insulation

Removing old attic insulation and installing a new one is not just a matter of waking up one day and starting without a plan.

According to Energy Star, the following are the essential considerations for removing and installing new attic insulation:

  • Do not install faced insulation over existing insulation: The paper or foil facing on faced insulation can restrict air movement, trapping moisture and promoting mold growth.
  • Remove all existing insulation: You should remove and replace the attic insulation, especially if you can see visible mold growth. Also, consider removing any insulation damaged by pests.
  • Fiberglass or cellulose insulation can be installed over existing insulation: An exception comes with cellulose and fiberglass insulation, which can be added on top of existing insulation. However, you should ensure that the new insulation does not compress the old one to reduce its R-value.
  • Roll out the insulation: To ensure an excellent fit, you should roll out the insulation perpendicular to the joists.
  • Test any vermiculite insulation: You should have a certified asbestos abatement contractor test any vermiculite insulation for safety before using it.
  • Cut the insulation to fit around obstacles: You might need to cut the insulation around barriers such as recessed lighting and pipes to achieve an excellent fit.
  • Seal the edges of the new insulation: Once installed, seal all gaps and spaces with caulk or spray foam to create an airtight seal.
  • Install baffles: Baffles are installed between the rafters to create a space for air to circulate and prevent the insulation from blocking soffit vents.

When Do You Need New Attic Insulation?

Knowing when your home needs new attic insulation can be challenging if you’re not an experienced contractor. However, there are a few telltale signs that you can use to know when your attic insulation needs an upgrade.

Some of the most common indicators that you need new attic insulation include:

  • Your energy bills have increased significantly: If your energy bills have increased, but you haven’t changed your energy consumption habits, it might be time to check your attic insulation.
  • The temperature in your home is inconsistent: If you notice that the temperature in your home is unstable, it might be because of poor attic insulation that needs replacing.
  • You can see or hear pests in your attic: If you start seeing or hearing pests in your attic, it might be time to replace the insulation. Pests can damage the insulation, making it less effective.
  • Your attic floor is sagging: A sagging attic floor may signify that the insulation has compressed over time, making it less effective.
  • There is visible mold growth on the insulation: Mold can cause health problems and damage your home. Therefore, the earlier you replace the insulation, the better for your home.

Read: Do You Have To Pay For Heat In An Apartment?

Final Thoughts

It’s advisable to remove old attic insulation before installing a new one for optimum operation and safety. If you’re unsure how to go about it, consider hiring a professional contractor to help you. A contractor can recommend the best attic insulation for your home based on the local weather.