How to Better Insulate Your Roof

In the winter, the right insulation can keep the heat inside your home. In the hot summer months, the insulation keeps the outside heat from coming through your roof from above.

Top 3 Reasons That Insulation Matters

1) Keeps your home warmer in cold weather.

2) Keeps your home cooler in hot weather.

3) Saves on ever-increasing energy bills.

Before you decide which kind of insulation is best for your roof, you need to know what geographic R-value climate your home is located within. For example, Marin, Napa, and Sonoma counties are all in Zone 3. In fact, much of California is in Zone 3. That means the roof insulation you choose needs an R value of R-38 to R-60.  What does that R stand for? Resistance to heat flow.

What Insulation Materials Are the Best?

Now that you know some basics, you’ll want to look at the insulation materials that are available. The “best” for your home, may differ from that of your neighbor. It will depend on your budget and your personal preference.

Fiberglass is the most common, whether it is blown fiberglass, applied through a tube and literally blown into your attic crawl space, or applied from batts. When it comes to batts (or rolls), mineral wool is another option and is considered environmentally friendly as it is made from 75% recycled content. If you are seeking more earth friendly options you might consider natural fibers like hemp, straw, cotton, or sheep’s wool.

Are You A Do-It-Yourself Kind Of Person?

 Many DIYers choose the fiberglass batt insulation because the material is relatively easy to work with, is light in weight, and readily available at your big box building stores. Let’s not forget, it is often the least expensive, too. Keep in mind, when working with insulation that has fiberglass, safe installation procedures are needed. Protect your eyes, skin, hands, and your lungs.

The fact that fiberglass batt insulation is light in weight also means it often has a lower R-value.  Some folks choose to double-up to increase the R-value. It depends on how high an R-value insulation material you need.

Other types of blown-in insulation are available but differ substantially. Aside from the blown in fiberglass, there is cellulose. Unlike non-flammable fiberglass, cellulose is flammable. However, it might prove to be sturdier than fiberglass. Blown insulation is great for areas that are hard to reach, like attic crawl spaces. In both cases, the material is prone to settling (flattening) lessening its effectiveness over time.  In addition, both these can collect moisture.

Call In the Professionals for Spray Foam

Call in the professionals for Spray Foam

The other option for insulation that can be blown in is spray foam insulation, usually made from polyurethane. Some other foams are made with phenolic, polyisocyanurate or cementitious.

Spray foam offers a higher R-value and is sprayed directly onto the underside of the roof. Or it can be sprayed onto an unfinished floor surface in an attic. You can utilize it for an entire area or spot hit those areas that may have cracks or appear susceptible to the accumulation of moisture. Spray foam is best applied by the professionals. Why? The foam contains chemicals that can irritate your skin, lungs and eyes and protective clothing must be worn.

The cost for this type of insulation, if used for the entire underside of the roof can run about $10,000 depending on the size or your home.

The choices don’t end here. Other options include:

  • Foam board or rigid foam
  • Structural insulated panels (SIPs)

How Do You Determine The R-Value Of A Particular Material?

  • Moderate Climates (R-38 to R-60):
  • Fiberglass (blown): 17” – 22”
  • Fiberglass (batts): 13” – 17”
  • Cellulose (blown): 13” – 16”
  • Rock Wool (loose): 15” – 22”
  • Foam (sprayed): 6” – 14”

For descriptions of each material,  provides full details.

Speak to a Marin Roofing Professional

With over 100 years experience, the team at Booth and Little Roofing can answer any question you have. Give us a call at 415-924-2733 right now.