How to Add Insulation to Attic?

How to Add Insulation to Attic?

Winter is officially upon us. The time of year for chunky sweaters, fires, and hot cocoa. Whether we’re driving on icy roads or shoveling snow in the morning, all of us have one thing in common—trying to keep the house warm. Our homes are our haven against the harsh winter weather. Many of us step through the front door expecting immediate warmth. Unfortunately, this isn’t the case for many homeowners. Just attempting to keep the house at a stable temperature can be a total struggle. Maybe you have the heater on for hours and hours, but somehow the heat never stays for long.

Did you know that attics are the result of over 80% of heat loss? Animals hibernate, grow denser coats, and store up food in preparation for winter, but many homeowners don’t fortify their attics against heat loss! You don’t have to be one of them. You can solve heat loss issues in the attic with proper insulation. Here, we’ll explain the basics on how to insulate an attic and reveal what’s necessary to get the job done right.

What type of insulation for attic?

Picking the right insulation could be a little daunting if you’ve never had to do it before. In this age, there are many kinds of insulations to choose from, so how do you know what’s right for you?

Insulation Control for your AtticCourtesy of Canva

If you don’t have any insulation at all in the attic, then the attic is your playing field. If you’ve already got existing insulation up there, (which most of us do) then it’s best to figure out what it is you do have and measure it out, asking yourself: how much attic insulation do I need to reach the desired R-value? Of course, even if you have existing insulation, sometimes it’s best to replace it altogether if it’s been soiled by moisture or a rodent infestation. Patch leaks and rodent proof the attic first before adding new insulation!

Once your attic is prepped, cleaned, and ready to go, it’s time to determine what kind of insulation would work best in your home. The two most common types are loose-fill and batt insulation.


This is a popular choice for those with existing insulation who’re looking to top off what they already have and reach a higher R-value. It’s ideal for attics with lots of grooves, and gaps, and obstructions that need to be worked around. The insulation fibers come packed in bags and need to be blown into desired areas using a machine that you can typically rent from a home improvement store.

You can find loose-fill insulations packaged with cellulose, fiberglass, and mineral wool. DIY homeowners looking for a fast, effective insulation method than some of the costlier ones, often opt for cellulose—a material made from recycled newspaper. This product is fused with chemicals that make it an excellent fire retardant and insect repellant. It’s one weakness is moisture, having been known to rot and grow mold upon contact with water. IT’s R-value per inch is 3.2-3.8.

Two other loose-fill materials are fiberglass and mineral wool. Both of which are also made of recycled materials. Fiberglass has a price that’s hard to beat, being made of recycled glass and sand. However, because fiberglass is the lightest in weight, it usually requires a significant amount of layering, which could become more labor-intensive in the long run. It can also irritate the skin when touched and should always be handled with gloves. It’s R-value per inch is 2.2-2.7.

Mineral wool, having fibers made of recycled rock and slag from blast furnaces, is a natural fire-resistant insulation. It’s heavier and easier to blow into place but has a higher price tag than the previously mentioned materials. Its R-value is 3.0-3.3.


This type of insulation comes in rolls and is designed to be cut, rolled, and stapled into place. Batts are ideal for attics that are mostly free of obstructions and random penetrations. Because they require much more work than loose-fill, batts are most often used in attics that are easier to move around in. It comes in all the same materials mentioned for loose-fill, plus one more! Cotton.

Cotton is made from recycled denim cloth and is much more expensive than the other materials. However, it has neat benefits in being able to block airflow and sound transmission. Its R-value is 3.7-3.8, having the same heat resistance as cellulose while lacking the ability to rot when exposed to water.

How to add insulation to attic

If you’ve decided to go the loose-fill route, then you’ll need to rent an insulation blower. Multiply the length by the width of your attic to get the square footage. Once you’ve got a number to work with, it’ll be much easier to decide how much attic insulation you’ll need to purchase. If all you intend to do is fill in the gaps that may be squandering valuable heat and costing you money, then you’ll likely be layering the loose-fill over the existing insulation. Pay careful attention to any insulation that is soiled or growing mold and remove that first. Be sure to patch any areas where moisture might be lurking, then use caulking and spray foam to seal the air gaps before blowing the insulation into place.

It’s always recommended that you wear protective gear, a mask, hard hat, and gloves to protect yourself against free-flowing insulation and nails protruding from the joists. You can lay a sheet of plywood across the joists to give you better footing in the attic. Never walk on the floor of the attic! This is your ceiling and you’ll likely fall through it.

Protection when adding Insulation to Attic Courtesy of Pexels

The same rules apply for installing batt insulation, except where loose-fill is mostly intended to fill gaps and tight spaces, batt or rolled insulation is designed to cover larger, easier-to-reach areas. Expect to measure the length and width between each of your joists, then cut and lay the insulation accordingly. When it comes to using batt insulation, it’s recommended that you use two layers—one layer in the spaces between the joists and another layer lying perpendicular to the joists. This is because airflow tends to escape from the cracks between the insulation and the joists.

When should I call in a professional?

If you’re experiencing roof damage, mold on the walls, or if there’s a rat infestation in your attic, it’s best to call in a professional. Mold can be extremely toxic to your health as well as difficult to remove. It requires careful attention to detail to properly destroy the spores and is a labor intensive, dangerous job for most homeowners.

Rat and mouse infestations are of no laughing matter either. Rodent feces and urine can create a dangerous mix within your insulation, kicking up mustard gas into the air when attempted to clean. Removing the soiled insulation will expose you to diseases if not handled correctly. Also, replacing the insulation right away will prove to be a useless task if the rodents are still present in the attic. You’ll need to rodent proof the attic first, then trap the remaining rodents and disinfect before adding new insulation.

Even if this is the case in your home, you may be in luck. The expert team at Green Rat Control is totally equipped to handle rat infestations, using products that are 100% safe for the environment. We will also remove and replace all damaged insulation and completely decontaminate the attic.

Get a free estimate today!