Attic insulation is a homeowner’s first line of defense against high heating or cooling bills. A properly insulated attic can spare you from experiencing drastic weather changes in your home. A properly insulated attic is also a preventative method against ice dams.

What is Insulation?

 Thermal insulators are materials that prevent or reduce forms of heat transfer. Insulator prevents the heat transfer whether the environment temperature is high or low.

Some of the advantage of thermal insulation is that it isolates the building from heat as well as reducing energy consumption; in turn reducing costs of air conditioning. It also keeps the indoor air temperature stable.

Types of Attic Insulation

Fiberglass Insulation: This is made from glass cullet and other melted raw materials that are spun into fibers. They resemble the texture of wool. It comes in batts, rolls, or loose-fill forms. Fiberglass insulation is most commonly used in sidewalls, attics, floors, crawl spaces, cathedral ceilings, and basements.

Mineral wool insulation (also called rock or slag wool insulation): This is made from rock, blast furnace slag, and other raw materials which are melted down. They are then spun into fibers they resemble the textures of wool. Mineral wool comes in batts, rolls, or loose-fill forms. Similar to fiberglass this is used in sidewalls, attics, floors, crawl spaces, cathedral ceilings, and basements.

Cellulose insulation: Made from cellulose fibers which are derive from paper, paperboard stock, or wood. It’s chemically treated to be fire-resistant.

Spray foam insulation: Spray foam is chemically-made by insulation contractors on site to create foam. It’s applied with a sprayer in attics and into wall cavities. There are two main types of spray foam which are open cell foam insulation and closed cell foam insulation.

Air Sealing

Air sealing is a seal that prevents air or vapor from passing through. 

Fiberglass, mineral wool, spray foam and loose fill cellulose require air sealing for these to function properly.

Spray foam does provide some air sealing when done correctly.

There isn’t currently any insulation product on the market that would create a whole-home air barrier. Any type of insulation requires air sealing.

How Does This Prevent Ice Dams?

If heat is finding its way from your conditioned living area into the attic you can get warm areas and cold areas, which may cause ice dams.

Preparation Before Installation

Heated or cooled air will escape if you have gaps in the attic or between the lower floors and the attic, making any insulation ineffective.

Fix roof leaks. Water is not a friend of insulation. It also ruins the air-trapping pockets blocking the heat flow. To spot leaks look for water stains on the roof sheathing or damp moldy spots on attic joints and existing insulation which gives you a clue where leaks might be.

Box out light fixtures. Don’t allow the material to or cover recessed cans or lights from the floor below. This is a fire hazard. Create a safety gap that’s at least 3 inches around all fixtures by using hardware cloth, metal flashing, or scrap plywood.

Direct all exhaust fans and vents to the exterior. This prevents humid exhaust air from becoming trapped.

Installation

With some insulation materials installing them yourself is definitely doable. Installing fiberglass or mineral wool insulation are simple DIY tasks. Other types of insulation like spray foam require a professional to install them.

Fiberglass and mineral wool installation- This method takes time and attention, but the quality of this method can be easily assessed.

Spray foam- It’s difficult to see gaps or void in the material on the application surface.