How thick should blown in insulation be?

When blown into attics and wall spaces, loose-fill fiberglass offers an average R-2.5 thermal value per inch (the higher the number, the greater the insulating effect). You'd need a thickness of about 7.5 inches of insulation to match the insulating value of a batt of R-19 insulation (R-19 is a common batt value).

Can you put too much blown insulation in your attic?

Can you over insulate your attic? The answer is yes! Past a certain point, insulation in a vented attic will do more harm than good. In most of the United States, achieving an R-Value of 38 is more than sufficient.

How many inches of blown in cellulose insulation do I need?

With blown-in cellulose insulation, that would require insulation to a depth of 10 inches. If there is already insulation, measure the current depth and subtract to determine the amount needed to bring the attic to the recommended level for the desired R-Value.

What is the R-value of 14 inches of blown insulation?

Cold Climates (R-49 to R-60):

Fiberglass (batts): 14” – 19” Cellulose (blown): 14” – 18” Rock Wool (loose): 17” – 25”

How thick should my attic insulation be?

The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.

How to Install Blown-in or Loose Fill Insulation

What is the R-value of 4 inch Styrofoam?

STYROFOAM extruded polystyrene insulation is rated at an R-value of 5.0 per inch at 75°F.

What is the R-value of 2 inches of blown insulation?

Blown-in fiberglass has an R-value of 2.2 to 2.7 per inch.

How thick should cellulose insulation be?

Cellulose insulation should be 8-19 inches deep in your attic. Generally, the proper depth of cellulose depends on the following factors: Desired R-value. Insulation density.

What R-value do I need for attic?

Depending on where you live and the part of your home you're insulating (walls, crawlspace, attic, etc.), you'll need a different R-Value. Typical recommendations for exterior walls are R-13 to R-23, while R-30, R-38 and R-49 are common for ceilings and attic spaces.

Which is better cellulose or fiberglass blown-in insulation?

At 3.5 per inch of material, the R-value of blown-in cellulose is 23% better per inch than fiberglass batts! According to research done at the Oak Ridge National Lab, fiberglass loses up to 50% of its R-value in very cold conditions; making cellulose a better choice for homes in northern climates.

How long does blown in insulation last?

How Long Does Blown in Attic Insulation Last? Regardless of what kind of insulation you choose, blown insulation is a permanent solution. Cellulose insulation lasts 20-30 years because it is made from recycled natural materials, whereas fiberglass materials will last much longer because it does not degrade.

What is the best R-value for 2x4 walls?

Insulation for 2x4 Walls

In most wall applications, you will use R-13 or R-15 kraft-faced fiberglass insulation rolls for these two-by-four stud walls. While rated differently, these two types of insulation are close enough in thickness that they can both fit into modern two-by-four wall systems.

Should I remove old attic insulation before adding new?

Expert contractors that specialize in insulation advise that removing old fiberglass insulation is best before installing new cellulose insulation because of possible mildew, mold, or rodent excrement.

Which blown insulation is best?

Fiberglass, cotton, and mineral wool can all work as loose-fill insulation material, but the far and away top choice for blown-in insulation is fiberglass. Contrary to batts insulation, blown-in fiberglass insulation is perfect for filling in tight voids around wiring, pipes, or any area with awkward framing.

How many inches thick is R30 insulation?

Rock Wool Batt Insulation

For R30 insulation, a thickness of 8.87 inches of rock wool batts should be used. This can be used in both wood and steel.

How many inches of blown insulation is R60?

If you have approximately 6" of existing insulation, you'll need to add an additional 17" to reach R-60. If you have approximately 10" of existing insulation, you'll need to add an additional 13" to reach R-60. If you have no insulation, you'll need 23" to reach R-60.

Why is cellulose insulation bad?

Cellulose insulation made of formaldehyde and small fibres are hazardous from environmental point of view. Individuals with preexisting skin disorders and asthma are allergic to cellulose, because of its itch inducing particles. The particles can be irritating to the eyes, skin, and lungs.

What is the R-value of 2 inch Styrofoam?

With an R-value of 13.1 for a 2" thick sheet only two 2" sheets are required to achieve R-25. 2. Extruded polystyrene or XPS (foam is usually pink or blue) XPS has an R-value of 5 per inch of thickness requiring 5" of insulation to achieve R-25.

How thick is r49 attic insulation?

A: Hello Shelly, Owens Corning R-49 Fiberglas Batt Insulation is 14" thick and will be compressed if installed into a 2x10 or 2x12 rafter. Compressing insulation will reduce the R-value of the product.

What insulation has the highest R-value per inch?

Vacuum insulated panels have the highest R-value, approximately R-45 (in U.S. units) per inch; aerogel has the next highest R-value (about R-10 to R-30 per inch), followed by polyurethane (PUR) and phenolic foam insulations with R-7 per inch.

What is the difference between pink and blue foam board?

Both are manufactured using the same process and contain similar chemical components. The two products also have the same insulating power. However, blue foam boards are manufactured by Dow Chemical Co. whereas the pink foam boards are manufactured by Owens Corning company.