Why You Should Remove Existing Insulation When Insulating Your Attic

If you're adding new insulation to your attic, you need to remove any existing insulation upstairs. It might feel counterintuitive to take away the insulation you already have. However, insulation removal is a vital step in this process. Not removing existing insulation could detrimentally impact the performance of the new insulation you're purchasing.

South Central Services has insulated hundreds of attics in and around Mercersburg, Pennsylvania. There are four reasons why existing insulation must be removed. By the end of this article, you'll know why you should get the old insulation out of your attic.

Don't have time to read right now? Check out everything you need to know at a glance.

1. Existing Attic Insulation Can Be Dirty Or Home To Pests.

The most common attic insulations are fiberglass batt and blown-in products. Both types of insulation can be a home for rodents. Pests will climb into batt insulation to create a nest. Blown-in insulation can also be a nesting material for rodents if rats or mice can get into your attic.

Inevitably, when rodents are living in your attic insulation, they will soil it with their droppings. Even if pest control measures are taken, and you no longer have any rodent infestations, their droppings will still be contaminating the insulation.

You do not want rodents or rodent droppings in your home. This is a health hazard. Covering up the nests or droppings with new insulation does not make the situation safe. It would also be a danger for whoever installs the insulation.

2. Existing Attic Insulation May Not Be Installed Properly.

If you've never had any issues with rodents, you still need to remove the existing insulation upstairs. The fact that you're investing in new insulation indicates that your current insulation isn't working.

Hypothetically, you could top off your existing insulation with new. Topping off insulation is actually a common method used for blown-in products when the initial insulation has settled enough to impact the R-value. However, that method only applies when the insulation was functioning correctly the first time.

Has your attic insulation ever made a significant dent in your energy costs or the comfort of your home? Topping off the insulation won't make these changes. There are likely issues with how the insulation was initially installed. To address these issues, the insulation must be removed.

Attic insulation is meant to decrease energy waste and lower energy bills. We don't insulate our homes just to insulate them but to make them more energy efficient and comfortable. If the insulation wasn't installed correctly, your energy costs will never decrease until the insulation is fixed.

It could be that baffles have been installed incorrectly or that the insulation is not contained in the attic properly. Any number of roof or attic issues could be at play. An insulation contractor can address these issues by starting with a clean slate.

It is best to cut your losses now and insulate correctly. You will waste more money if you install more insulation on top of the existing insulation.

3. Existing Attic Insulation Blocks Air-Sealing Measures.

No matter what insulation you choose for your attic, you need to air-seal. Even if you select budget-friendly insulation like blown-in cellulose, air-sealing is necessary to maximize its performance. Budget-friendly insulations cannot air-seal on their own, which results in energy waste through air leakage.

An insulation contractor cannot install an air-seal with existing insulation in the way. Air-sealing your attic floor means identifying gaps, holes, cracks, and other air leaks. Once these areas are addressed, heat can no longer escape at random through air leakage.

If your current insulation isn't cutting it, you want to invest in something that will make an improvement. A budget-friendly attic insulation paired with an airtight seal is the most affordable way to lower energy costs.

Without removing that existing insulation, the air leaks in the attic can never be identified. The investment in new insulation won't offer much of an improvement.

4. Existing Attic Insulation Prevents Spray Foam From Adhering.

If you're less concerned about budget, you may want to invest in the best-performing insulation for your attic. Premium insulation like spray foam will deliver the most improvement. However, spray foam cannot be installed where existing insulation is.

Spray foam insulation requires a clean surface to adhere to. It cannot be installed on top of batts or blown-in insulation.

The difference between spray foam and more budget-friendly insulations is the ability to air-seal. While batts and blown-in products need a separate air-sealing product, spray foam insulates and air-seals on its own.

When spray foam adheres and expands, it sticks like glue to the surface and seals any leaks in the attic floor. It also delivers a high R-value to help combat conductive heat transfer.

If you have the money to invest in spray foam insulation for your attic, removing existing insulation is a given. It can be frustrating to have existing insulation removed. Sometimes, it feels like your previous investment is being thrown away. However, if you won't get rid of the insulation that isn't working, you would be making an investment that would have to be thrown away.

The goal of new insulation is an improvement. Old insulation has to be replaced if any improvement is going to be seen.

The Bottom Line About Removing Existing Attic Insulation

You must remove existing attic insulation when you have new insulation installed. Existing insulation can hide rodent nests, droppings, mold, mildew, or other moisture issues. The insulation likely was never installed correctly in the first place, and it covers up air leaks in the attic floor.

As long as you're replacing your insulation upstairs, it's best to make the most of that investment. By removing existing insulation and air-sealing your attic floor, you'll have lower energy bills, better air quality, and a more comfortable home.

Now that you understand why existing attic insulation must be removed before adding new, your next step is to:

• Learn why you should air-seal your attic
• Compare blown-in cellulose insulation with spray foam
• Estimate the cost of blown-in insulation with an airtight seal