How much insulation is too much?

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.

Can you put too much insulation in?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

What happens if you double up insulation?

ABOUT INSULATION

The thermal barrier of a home should consist of a continuous layer of insulation on all sides—including the lowest floor, the exterior walls, and the ceiling or roof. Doubling the thickness of insulation will double the insulation's R-value, cutting heat loss in half.

What is a good level of insulation?

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. See the Department of Energy's (DOE) ranges for recommended levels of insulation below.

How much insulation should I have in my attic?

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 much Insulation Do I Need? Expert advice.

Can you put too much insulation in an attic?

It's possible to over-insulate an attic as too much will cause moisture buildup and eventually result in mold. Eventually, adding more insulation leads to diminishing returns in trapping heat as well.

Is 6 inches of attic insulation enough?

Most joists are six to seven inches tall, and if they are completely filled with material, they are insulated at R-21. However, the DOE recommends that attics in Southern homes be insulated with 13 to 14 inches, or R-38, of insulation at minimum.

What is a good R-value for interior walls?

Depending on the insulation properties of the existing wall, in general the R-values of the renovated walls can be between R-19 and R-22 (0.25 to 0.30 W / m² K) - without additional risk to the structure.

Is R-30 insulation Good for attic?

The average recommended level is 14 inches of R49. In Zone 2, the average minimum requirement for attic insulation is 9 inches of R30 fill. The average recommended level is 17 inches of R60. In Zone 3, the average minimum requirement for attic insulation is 9 inches of R30 fill.

Does insulation lose R-value over time?

Yes. Cellulose insulation does lose its R-value when it is compressed. The amount of loss depends on how much insulation is decompressed but typically ranges anywhere from 15% to 20% of its initial value.

Can you put 2 layers of insulation?

You should install two layers of insulation in your attic; wood joists must be covered to allow the air to move. The first layer will sit between the joists, and the second layer will run perpendicular over the joists. The first layer should have the facing against the drywall to act as a vapor barrier.

Can I put new insulation on top of old?

Yes! You can absolutely new insulation over old insulation… as long as it isn't wet. Energy Star advises as follows: “If it… appears that the insulation [is wet or] has previously been wet, you should look for the cause and repair the problem to prevent a reoccurrence.

Should you remove old 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.

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.

Will adding more insulation attic make difference?

In the simplest terms, R-Value is the degree to which your attic insulation is able to block heat from either escaping or entering your home. Insulation with a higher R-Value is successfully able to slow heat from being transferred out of your home in the winter and into your home in the summer.

Is R60 too much insulation?

Recommended R-Value Varies by State

You need exactly as much as the area you live in determines. Here, where temps get pretty hot for much of the year, attics should have from R30 to R60 (average is R38). Those living up north want anything from R49 to R60. This helps insulate against the extreme cold weather.

Is R-38 insulation Good for attic?

So, for your attic insulation, we have a minimum standard of R-38, and a recommended standard of R-49. R-Value is explained as thus: “the resistance, or strength of a material to slowing down the flow (movement) of heat”.

Is it worth insulating internal walls?

As much as 35% of heat loss occurs through insufficiently insulated walls. Therefore installing a thermal layer inside the home can significantly reduce your energy bills. It will improve ventilation and reduce condensation and working with the right experts mean you can make it hassle free.

Is it common to insulate interior walls?

While it's uncommon for most interior walls to be insulated, it's a relatively low-cost, high benefit job using batt or blown-in fiberglass or mineral wool insulation. With most people spending extra time indoors, there couldn't be a better time to offer this beneficial option.

Is r13 insulation good for garage walls?

If your exterior walls are constructed from 2-by-4 inch studs, the most insulation that can go into the wall while retaining its R-value is R-13 or R-15 as these are both made to fit a cavity 3 1/2 inches deep.

How do you tell if attic is well insulated?

How do I know if I need more insulation in my attic?

Looking across your attic, if the insulation is level with or below the attic floor joists, you probably need to add more insulation. Assumes R-3/inch. If you cannot see any of the floor joists because the insulation is well above them, you probably have enough, and adding more insulation may not be cost-effective.

What R-value is 6 inches of insulation?

Fiberglass blankets or rolls provide an R-value of up to 3.2 per inch, so a 6-inch fiberglass batt may achieve an R-value of 19.2, and some high-performance products are rated at R-21.

How often should insulation be replaced?

Unless damaged, it can last 80 to 100 years in most houses before it needs to be replaced. However, insulation can start falling from fiberglass batts after 15 to 20 years, so if your insulation was installed in batts well over a decade ago, it might be time for an inspection or a home energy audit.