NORTHWEST HOUSTON Blog

What is Blown-In Insulation?

In the world of insulation, there are multiple methods of insulating a structure and different products out there for different purposes.  Blown-in insulation is a common insulation choice and it can be done in both finished and unfinished walls and joists. This insulation works by filling studs, joist cavities, and floors with loose insulating materials.

There are two types of blown-in insulation to choose from based on use: loose-fill and dense-pack.

Loose-fill 

Loose-fill is the most common type of blown-in insulation. Here at Koala Insulation, we use a mechanical blower to blow the materials to fill even the tiniest space. The loose materials are first kept in a large bag and then loaded onto the machine which churns and mixes the material with air, just like cream in a kitchen mixer! 

The result? A fluffy insulation!

Loose-fill type of blown-in insulation is an ideal choice if you’re looking for insulation in a retrofit scenario in attic spaces and wall cavities.

Dense-pack

Another type of blown-in insulation is dense-pack insulation. It is like loose-fill insulation, except that the loose-fill materials in this method are blown in at a high pressure, resulting in a densely-packed insulation.

Dense-pack insulation is appropriate for retrofitting older houses with cathedral ceilings and closed-stud walls. In enclosed walls, holes are drilled on the wall cavities from which the loose-fill materials are blown in high-pressure, filling spaces in a compact manner.

If you want to insulate existing and enclosed walls, dense-pack blown-in is the best solution. 

What is Blown-in Insulation made of? 

There are three common materials for blown-in insulation: fiberglass, cellulose, and rockwool. Read on about these materials, their components, and characteristics to see which option is a suitable contender for your insulation needs.

Fiberglass

Spun from tiny glass fibers, fiberglass is an effective, lightweight, and inexpensive insulating material. Since glass is made of sand, an abundant material, it makes fiberglass a sustainable material. It is one of the most commonly-used materials for blown-in insulation.

Fiberglass usually has an R-value of 2.2 to 2.7 per square inch. It has tiny air pockets from which it derives its thermal resistance. The thicker the insulation, the greater the air and its R-value.
 

Fiberglass is fire-resistant and waterproof. It is important to note that water can still penetrate its fibers. Once wet, it temporarily loses some of its R-value but after fiberglass is fully dried it can maintain its form (uncompressed) and regain its full insulative properties.

If left undamaged, this material can last about 80-100 years-- but factors like compression, weather and age can affect fiberglass. 10-15 years after insulation, fiberglass usually starts to sag.

Cellulose

If you want a sustainable insulating material, cellulose is another alternative. It is made up of 75-85% of recycled newsprint, paper or any wood by-product. The remaining 15-25% is composed of chemicals like boric acid or ammonium sulphate. These chemicals are in cellulose to make the product more resistant to fire, molds, and pests.  

Cellulose has an R-value of 3.2 to 3.8 per square inch and blocks air leaks effectively especially if it is densely-packed.

To keep cellulose at its top insulative performance, keep it from any sources of moisture. Make sure to air seal every corner before you insulate! Its tiny granules can fall between light fixtures, air vents, and more if not properly air sealed.  Once cellulose is soaked with water, it will lose some of its insulating properties as well as its chemical treatments. It can also settle and sag once saturated with water.

Cellulose insulation can last around 20-30 years but due to moisture and other factors that can cause damage, it can sag and settle within 10 years.
 

Rockwool

This mineral wool is a man-made material from natural minerals like basalt or diabase, and slag. Rockwool is naturally non-flammable as it has a high melting point of more than 1000°C, making it more non-combustible than cellulose and fiberglass.
 

Rockwool’s R-value ranges from 3 to 3.3 per square inch. Aside from blocking heat, this material provides superior noise-blocking properties.

Rockwool does not lose its R-value once wet but if left with water, it can still cause moisture problems in the attic. A properly installed rockwool insulation can last up to many decades if it isn’t exposed to physical damage.

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Do you want to know if blown-in insulation is the right solution for you and your home? You can check out our comparison chart here or better yet, call Koala Insulation of Northwest Houston to book your free insulation evaluation ! Our insulation experts can walk you through your insulation options to ensure a great experience!