Should old blown in insulation be removed?

Author: Noah Gorczany  |  Last update: Wednesday, November 26, 2025

Removing old insulation is generally recommended if it's damaged, contaminated with mold, or infested with pests. However, if the insulation is in decent shape and just needs a boost, adding a new layer on top can be a cost-effective option.

Do I need to remove old blown insulation?

Insulation needs to have room to expand to its full size to be effective, so the old definitely needs to be removed. Not to mention the old stuff is full of dust, probably some rodent excrement, and who knows what else that has accumulated in your attic over the years, so that's another reason to get rid of it.

Should you remove old roof insulation?

Condition of Existing Insulation: - If the old insulation is in good condition (not wet, moldy, or damaged), it may be acceptable to leave it in place. However, if it shows signs of deterioration or contamination, it should be removed.

What can I do with old blown-in insulation?

Call your local waste-management office and ask what to do with the insulation of your type. In some cases, you can place the bags out with your regular trash. In others, you will have to take it to a designated area at the dump.

Do insulation installers remove old insulation?

Any reputable insulation installer will thoroughly remove old insulation before putting in the new. However, as a homeowner, you should double-check that they remove all of the old insulation as a first step.

When Should You Remove Old Attic Insulation?

How much does it cost to have blown-in insulation removed?

With all factors considered, the average attic junk and insulation removal costs around $1.50–$3 per square foot. If there's mold present, however, costs lean toward the top of that range or over — approximately $4.5–$6 per square foot.

Is it OK to put new insulation over old insulation?

In many cases you can add new insulation on top of old insulation, unless the old insulation is wet, mouldy, or vermiculite. If the old insulation is dry but appears to have previously been wet, you should look for the cause and repair the problem.

What is the life expectancy of blown in insulation?

Blown-in insulation, available in fiberglass and cellulose varieties, generally lasts 20 to 30 years. Fiberglass tends to be the more durable option, while cellulose is more sensitive to humidity, which can affect its longevity in certain climates.

Where can I dispose of blown in insulation?

If you're dealing with either of these types of insulation, call your local recycling facility to see if they accept insulation and set up a dropoff appointment.

How often should you replace blown in insulation?

Blown-In Insulation (Fiberglass And Cellulose)

Because it is both efficient and economical, blown-in or loose-fill fiberglass is an insulation material that sees widespread use. In most homes, loose-fill insulation can survive anywhere from 80 to 100 years before needing replacement, provided that it is not damaged.

Should I replace 50 year old insulation?

Unfortunately, the majority of homes built 50 years ago were not insulated at all. It is important to be aware of these insulation issues if your home is 50+ years old. Replacement (or new installation) may be necessary if your home is drafty, if you have high utility bills, etc.

Do roofers remove insulation?

In fact, homes with unfinished attics may have no rafter insulation at all — instead, they rely on fiberglass batts or blown insulation installed between the joists on the floor. In either case, though, your insulation should generally remain untouched while the roofer does their job.

Can you put too much insulation in a roof?

Yes, too much loft insulation can cause dampness in some situations. Loft insulation works by trapping warm air inside a building, preventing it from escaping through the roof. This helps to keep the interior of the building warmer in cold weather, reducing the need for heating and saving energy.

Is it worth replacing blown insulation?

If you live in an older home, it may be time to remove your old blown in insulation material. A proper replacement will help lower utility bills, retain the value of your property, and keep you and your family comfortable all year round.

Can I use a shop vac to remove insulation?

It's going to get everywhere and make an even bigger mess, so you will need to get a vacuum to remove insulation from the attic. We use a 1,500-horsepower shop vac when we do the removal, and in most cases, hook that to a second attic insulation removal vacuum to get the suction we need.

Can you remove blown in insulation yourself?

The preferred method of removing blown in insulation is by machine, using a vacuum process to suck the insulation out of the attic. This is the most efficient option and can save both time and money. If you're doing the removal yourself, you'll need to rent a high-powered insulation vacuum.

Should you get rid of old insulation?

Generally speaking, replacing old insulation may not be worth it if old insulation is dry, free of dust and it is not squashed. In this case, its removal isn't necessary. In fact, it can be quite beneficial to leave old insulation.

Why is blown in insulation bad?

Moisture Sensitivity: One of the major drawbacks of blown-in insulation is its susceptibility to moisture. If your attic has a moisture problem or experiences water leaks, the insulation can become damp, leading to mold growth and reduced effectiveness.

Can you reuse old blown in insulation?

While it varies by type, blown-in cellulose is a type of insulation that can typically be recycled. The blower tool deploys the material to fill wall cavities, making it ideal for hard-to-reach spaces and poorly insulated areas in attics or crawl spaces.

Is blown in insulation bad for your lungs?

Blown-In Cellulose Particles Are Paper.

Unlike glass fibers, cellulose isn't dangerous to breathe. However, it can irritate your lungs. If you have pre-existing allergies, the dust of cellulose insulation can be obnoxious.

Is it worth removing old insulation?

Indoor air quality: You can improve the air quality in your home by removing old insulation that may harbor mold, dust or allergens. Increased home comfort: New insulation helps regulate indoor temperatures more effectively, eliminating hot or cold spots and even reducing noise.

Can you put too much blown insulation in your attic?

Mold and Mildew Growth

Having too much insulation in your attic can allow for the accumulation of moisture. This leads to mold and mildew growth, which can be extremely bad for your health.

Should I replace 20 year old insulation?

However, insulation can start falling from fiberglass batts after 15 to 20 years, so if your insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.

Previous article
Can I shower with new caulk?
Next article
Can you eat lettuce instead of drinking water?