Fiberglass Chart

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What is the thickness of R-38 insulation?

The R-38 high-performance batts are 10˝ to 10-1/4˝ thick as opposed to stan- dard R-38 fiber glass insulation batts of 12˝.

Is R38 attic insulation enough?

The higher the R-Value, the better the thermal performance of the insulation. The recommended level for most attics is to insulate to R-38 or about 10 to 14 inches, depending on insulation type.

How thick is R30 attic insulation?

Typical R-30 fiberglass insulation is 10-inches-thick. Prior to buying fiberglass insulation, it is important to measure the joint spacing you are working with. Note that the actual space between the framing members will be less than 16 or 24 inches, but the foam batts can easily be stuffed between these lengths.

What is the R-value of 4 inches of blown insulation?

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

How do you get a R38 on the ceiling?

An insulation value of R-38 is at the high end and requires a minimum thickness of 12 inches. R-value does not depend on a single layer of insulation. To achieve R-38, you can use two layers of R-19 or three layers of R-13, which give slightly higher thermal resistance.

Is R49 better than R-38?

A ceiling with an R-value of 38 lets through only 1/38 of the amount of energy per square foot that passes through that window, or about 2.6% of the energy; a ceiling with an R-value of 49 lets through only 1/49 of the amount of energy per square foot that passes through that window, or about 2.0 % of the energy.

What R-value is needed for ceiling insulation?

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.

Can you have too much insulation in an 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 do you need for R30?

If your attic has fiberglass material, 5 inches gives about an R-11 insulation level, 8 to 9 inches around R-19, 12 inches R-26 and 13 to 14 inches is around R-30.

What is the R-value of 1 foot of blown insulation?

R-Value of Insulation by Type Fiberglass (blown): 2.2 – 2.9. Fiberglass (batts): 2.9 – 3.8. Cellulose (blown): 3.1 – 3.8. Rock Wool (loose): 2.2 – 3.3.

How thick does blown insulation need to 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).

How many inches of insulation is R60?

The average recommended level is 17 inches of R60.