Quick Answer: Can You Over Insulate A Wall?

What is the R value of 12 inches of blown insulation?

R-value of Materials and DepthsMaterialR-value/in12″Fiberglass blown (attic)2.2 – 4.326.4 – 51.6Fiberglass blown (wall)3.7 – 4.344.4 – 51.6Mineral Wool (batt)3.1 – 3.437.2 – 40.832 more rows•Feb 6, 2013.

What is the best cavity wall insulation?

Foam FoamFoam. Foam offers the best thermal cavity wall insulation, but installation is tricky and needs expert attention, and some foams have been known to degrade in the long term.

Should I remove old attic insulation before adding new?

According to ENERGY STAR®, you can put new insulation over old insulation, “unless it is wet. … “Faced” insulation should not be placed on top of existing insulation in the attic. Any new roll or batt insulation installed over existing insulation in the attic needs to be without a vapor retarder (face).

Can you lay insulation over electrical wires in attic?

It’s caveman simple to install residential attic insulation batts on top of an existing ceiling when you’re in an attic. … Don’t step on any cables or wires in the attic.

Can too much insulation cause mold?

Tightly sealed windows are an important part of insulating a home. There can be too much of a good thing, insulation included. … But several readers mentioned that going overboard with insulation and sealing a house can cause serious problems – from moisture buildup and mold to polluted indoor air.

Can you put too much insulation in attic?

But there may be a theoretical point of “too much.” If a home is over-insulated and is too tightly sealed, moisture can get trapped inside. Without proper ventilation, a home can build up too much moisture, especially in the attic (warm air rises), which can cause mold problems and, overall, lower indoor air quality.

Is blown in insulation better than rolls?

The environmentalists in your family will likely favor it over the rolled kind of fiberglass insulation. Blown fiberglass insulation scores an R-value of 3.2 to 3.8, making it slightly less likely than rolled fiberglass to prevent the flow of heat into and out of your house.

What are the disadvantages of cavity wall insulation?

General Cavity Insulation Disadvantages: If moisture gets into your cavity insulation, its ability to keep your home warm will diminish. Cavity fill insulation means you’ll no longer have a void in the cavity to prevent moisture getting across to the inner leaf of the wall. If poorly fitted it won’t be as effective.

How much installation should be in the 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.

When should you replace wall insulation?

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.

What are the disadvantages of insulation?

No type of insulation completely stops heat transfer and fiberglass has other drawbacks, as well.Coverage Issues. Fiberglass batts are available in precut widths of 16 inches or 24 inches. … Air Exchange Issues. … Moisture Issues. … Mold Issues.

What does the R mean for insulation?

resistance to heat flow”R” means resistance to heat flow. The higher the R-value, the greater the insulating power. Almost all insulation products have to tell you their R-value — pipe and duct insulation are the only exceptions.

Can mold grow on spray foam insulation?

As a product, spray foam insulation does not attract mold. And unlike wood or metal, spray foam does not rot, rust or deteriorate. … It will control indoor humidity and condensation, and therefore prevent mold from growing and spreading.

Can you double up insulation?

Doubling the thickness of insulation will double the insulation’s R-value, cutting heat loss in half. … In some cases, like an attic, it’s worth piling on more insulation because there is plenty of room. It’s much more expensive to add that much insulation to exterior walls.

Can you put insulation over existing insulation?

You can absolutely new insulation over old insulation… as long as it isn’t wet. … Remove any wet insulation. Wet insulation can lead to mold, mildew, or even the rotting of your ceiling or roof rafters.” In fact, you can add new insulation over the existing installation in other areas of your home, not just the attic.

How thick is r60 insulation?

17 inchesThe average recommended level is 17 inches of R60.