Attic Insulation 101: Everything You Need to Know

  • Written by: Killingsworth Environmental
  • January 07, 2019
So you’re insulating your attic. Or maybe you’re considering re-insulating your attic. Either way–we’ve got you covered. Below is everything you need to know about insulating your attic. Let’s get started!

Why is attic insulation so important?

We’re glad you asked. As we’re sure you know, your attic covers the entirety of your home. Any air that is conducted into the rest of your house begins with the attic. Therefore, making sure that your attic is insulated properly is imperative to the health of the rest of the home. Without a properly insulated attic, it’s likely that your heating and cooling system will have to work harder to keep the rest of your house at the desired temperature. And with all that work from your HVAC unit comes much higher energy bills. Who wants that?!

Additionally, an attic that is poorly insulated (or not insulated at all) will allow for excess moisture in the areas that aren’t insulated. Though this may not seem like a huge problem, moisture build up will eventually lead to some bigger, more concerning issues–like mold growth. Once mold begins to grow in your attic, it soon begins to hinder the air quality of your home. Though not easy to get rid of, fortunately mold remediation can take care of this problem.

Lastly, substandard insulation in your attic can lead to some significant pest problems. In times like winter when the weather gets cold and gross, pests like rodents, cockroaches, spiders and more are looking for a warm place to go. Notoriously, pests like these find their way to attics. With proper insulation and air sealing, pests have no way to get in. However, issues like old and worn insulation make it easy for pests to chew their way into your home. Yuck!

The Basics of Attic Insulation

Before we begin, let’s go over some basic attic insulation terms:

Insulation is the material installed in walls, ceilings, floors and in this case–attics! This material

Heat transfer, or heat transmission, is the movement of heat through one material to another (which is what insulation is meant to prevent)

Faced insulation has a vapor barrier that helps prevent moisture from moving from one space to another or when downward heat flow needs to be prevented (i.e. fiberglass batts)

Unfaced insulation is used when new insulation is being added to existing insulation (i.e. spray foam and fiberglass)

R-value is the capacity of an insulating material to resist heat flow. The higher the R-value, the greater the insulating power.

Closed-cell SPF is a form of spray foam insulation that provides added structural strength and hard vapor protection

Open-cell SPF is a form of spray foam insulation that offers the same insulation benefits as closed-cell but doesn’t act as a water or vapor barrier

Now that we’ve gone over the basics, let’s take a look at the most common forms insulation for attics.

Most common attic insulation materials

The type of insulation you use in your attic will depend on how old your home is and what you’re looking to get out of the insulation. As we know, some common reasons why homeowners try to keep up on their attic insulation is to: reduce energy expenses, prevent moisture and mold, protect your home from pests, and more. Below are a few common attic insulation materials and their benefits.

Loose-fill and Blown-in Insulation

Loose fill (or blown-in insulation) is a highly eco-friendly and energy efficient form of insulation. With its high percentage of recycled content, loose-fill insulation provides a dense, effective barrier against heat loss–which is something attics see a lot of.

Best for…

  • Attics with• irregular or nonstandard joist spacing
  • Attics with• lots of obstructions and penetrations to work around
  • Attics with pre-existing insulation that needs to be added to
  • Low-clearance attics withlimited headroom for maneuvering 
during installation
  • DIYers who want to get the job done quickly and are comfortable 
working with power equipment

Spray Foam Insulation

Spray foam insulation, also known as spray polyurethane foam (SPF) insulation, is the most advanced, energy-efficient insulation on the market. You can choose between open-cell SPF which, as we know, offers structural strength with a vapor barrier. Or you can choose closed-cell SPF which offers structural strength without the vapor barrier.

Best for…

  • Attics that need protection against all 6 paths of heating and cooling loss (conduction, convection, radiation, air infiltration, moisture accumulation and air intrusion)
  • Attics that experience lots of moisture as it serves as a powerful mold deterrent
  • Attics with pest control issues; this insulation is not a source of food for pests


Fiberglass Batt Insulation

Fiberglass insulation is made of fine glass fibers and anywhere from 25 to 50% recycled content. It’s R-value ranges anywhere from R-8 to R-38, making it highly heat resistant. This insulation is the most cost effective and arguably the quickest to install yourself.

Best for…

  • Attics with standard joist spacing, especially those with no insulation
  • Attics with few obstructions or penetrations to work around
  • Attics with sufficient headroom for maneuvering during installation
  • •DIYers who don’t mind cutting the material to fit around obstructions

Doing it Yourself?

If you’ve decided to try attic insulation on your own, we’d like to help you get started! As you might recall, using a loose-fill or blown-in insulation is great for adding to pre-existing insulation–and tends to be a lot easier to install yourself. When going at it alone, though, it’s important that you set yourself up for success. Below is a checklist of items to complete before beginning your insulation process.

Before you start…

  • Seal air leaks around windows
  • Seal air leaks around pipes, wires, exhaust fans and ducts
  • Seal air leaks around chimneys and flues
  • Fix/repair roof leaks
  • Box out light fixtures
  • Direct exhaust fans and vents to the exteriors

As fun as it sounds, insulating your attic yourself is quite a large task. And while we hope that this article has given you some insight on what type of insulation you should choose for your attic, hiring someone who is trained to know just what you need is a sure-fire way to get the job done.

At Killingsworth, our team goes the extra mile to ensure you have the best insulation – best for your home AND best for the environment. That’s why we use KAP Pest Control Insulation. It uses recycled material to offer a unique and proven method of pest control that is great for the environment and has superior thermal and sound – deadening properties for your home.

If your attic is poorly insulated, or you’re in need of a complete insulation project, Killingsworth is here to help. As mentioned before, poor insulation jobs can lead to mold growth in your attic which can travel into the rest of your home. Mold and mildew can create huge health problems to your family as well as structural problems to your home. Download our Ultimate Guide to Mold and Mil-dews & Dont’s to learn more.

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