How effective is roof insulation?

roof insulation

What is roofing insulation? 

The purpose of the roof of your home is to protect you and your belongings from the climate and elements. However, it doesn’t do a thorough job of keeping cool or warm air inside your house. It needs roof insulation to ensure that the cool or warm air doesn’t escape through the rooftop. 

Roof insulation is a secondary barrier to ceiling, attic, and walls. Roof insulation comes in R-Value ratings, which is an industry-standard in measuring the insulating capacity. Home in northern areas that have a cold climate, the higher the R-Value the better insulation. 

Does roof insulation make a difference?

For most homeowners, cooling and heating their home accounts for almost half of their energy expenses, which leads most of us to seek a way to lower those costs. One way to reduce that expense is by adding roof insulation to your home. 

We learn in elementary science that heat rises. During the winter, you lose most of your heat through the attic. During the summer, as much as 20% of our air conditioning is going through the attic. Roof insulation can increase the efficiency of your home by keeping the cool air and warm air where they should be – in the main part of the house, keeping everyone comfortable. 

So, what type of roof insulation is best? The best roof insulation material is rigid foam boards or and spray foam insulation. They commonly apply spray foam between attic rafters and act as roof insulation and waterproofing by providing not only high R-value insulation, but a moisture barrier too. 

The rigid foam insulation comes in various thicknesses in panels or sheets and is roof insulation with plywood, installed between the rafters of the attic, directly under the attic rafters, or both. It also provides not just roof insulation, but a moisture barrier, too, and is high R-value rated. 

What is the best insulation for roofs?

There are two key types of roof insulation product:

  • Bulk – Largely affects transfer heat flow between touching objects
  • Reflective foil – Mainly affects the radiation of the heat flow.

Bulk roof insulation is the best because it traps the still air pockets within its structure, which provides resistance to heat flow, creating an insulating effect. Bulk roof insulation should not be compressed, which reduces the number of air pockets and lose insulating properties. Bulk roof insulation is available: 

  • Blanket or Batts – best for flat ceilings and pitched metal roofing or tile roofing.
  • Board Insulation – best for cathedral ceilings where space is limited between the ceiling and roof.
  • Loose-Fill Insulation – used in ceilings but because it loses its effectiveness over time faster, it is not the best roof insulation to use.

Should you insulate roof rafters?

An attic needs to be ventilated in order to prevent ice dams when the weather is wet and below freezing. By applying roof insulation between the rafters, the heat can’t get to those areas where ice dams form. If you feel that you need to apply roof insulation between the rafters, experts recommend using Icynene. This is expensive but an effective roof insulation and the ROI will take decades. 

The U.S. Department of Energy recommends a home to have roof insulation and wall insulation to get optimum energy efficiency. Areas recommended are the attic, the attic access door, including the joist space, exterior walls, and unheated garages, especially if the water heater is in the garage or on an exterior wall.

spray foam insulation

How long does roof insulation last?

Most homeowners that purchase a previous-owned property are not aware of how old the roof insulation is and will often estimate its value. If a home has spray foam roof insulation combined with house wrap insulation and wraps tape, have an average lifespan of 80 years or longer according to the International Association of Certified Home Inspectors. Other types of roof insulation like cellulose, foam board, loose-fill, loose-fill & rock wool insulation last a hundred years.

Roof insulation is durable, and the materials used today are resistant to humidity and weather. However, there are some factors that can weaken roof insulation, such as water, aka roof leak. Another factor that can affect roof insulation is punctures. The whole length of roof insulation becomes ineffective when any part of it is punctured.

Cellulose, fiberglass, or any batt roof insulation can come off the attic ceiling and crawl space around its 15th year of installation. The empty spots left are prone to mold growth and become dirty and dusty, making it less effective.

Roof insulation has several benefits for your home and your family.  Among them are:

  • Increases your home’s comfort and living environment.
  • Increases outside sounds.
  • Increases your home’s energy efficiency by keeping your home cool in the summer and warm in the winter, requiring less use of appliances such as air conditioners and heaters.
  • Reduces your home’s environmental footprint and impact.

With these four things in mind, choose the best installation your budget can afford, keeping in mind that it may cost you now, but the savings over the long run will be many, for you and the environment. Call 865-238-2628 today for your roof insulation needs in Knoxville and Chattanooga, TN.