In general, either batt or rolled insulation or blown
The answer is yes, you can put new insulation over old. But there are some circumstances that would require insulation removal first, such as in the case of contaminated insulation from pests, water or smoke. Moisture is the biggest culprit, as it can lead to mold and mildew, as well as ceiling and roof rafter rot.
As a general guideline, it's advisable to install double layers of thermal insulation throughout your house. Nevertheless, this may not be feasible in all areas due to space limitations. Typically, it's not practical to add two layers of insulation within the walls of your home.
Insulation needs to have room to expand to its full size to be effective, so the old definitely needs to be removed. Not to mention the old stuff is full of dust, probably some rodent excrement, and who knows what else that has accumulated in your attic over the years, so that's another reason to get rid of it.
Any reputable insulation installer will thoroughly remove old insulation before putting in the new. However, as a homeowner, you should double-check that they remove all of the old insulation as a first step.
In general, either batt or rolled insulation or blown loose-fill insulation (fiberglass or cellulose) can be installed on top of old insulation. If you need to add new insulation on top of old insulation please note the following: Draftproofing should be completed prior to the addition of more insulation.
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.
Leaving Too Many Gaps
One of the biggest problems DIY homeowners face is leaving too many gaps in their insulation. Gaps or insulation that isn't secured correctly can leave the building structure open to air and moisture leaks. Spray foam insulation is best for reaching into small cracks and any areas left open.
R19 Insulation offers superior thermal insulation compared to R13. With a typical thickness of 6.25 inches, R19 fiberglass is designed for use in 2x6 wall cavities, making them suitable for colder climates where higher thermal resistance is necessary.
The recommended thickness for attics is typically 12-16 inches. Spray foam insulation: As discussed earlier, the recommended spray foam insulation thickness can vary depending on factors like climate and location. For attics, a thickness of 2-4 inches is usually sufficient.
The primary purpose of double insulation is to protect the user from the risk of electric shock. If the first layer of insulation fails for any reason, the second layer acts as a backup, preventing any live parts from becoming exposed.
The average U.S. homeowner spends about $1,852 to install insulation. Depending on the type of insulation, square footage, site location, and material, you might spend anywhere from $498 to $4,500. Insulation can keep your home cozy and warm on long winter nights or cool and comfortable on hot sunny days.
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.
Benefits of upgrading insulation in an older home
The most significant advantage is improved energy efficiency, which can lead to substantial cost savings on heating and cooling bills. Properly installed and effective insulation can reduce energy usage by up to 20%, making it a worthwhile investment for any homeowner.
The Big Question: Do I Need to Remove Old Insulation Before Installing New? In the majority of cases, removal of old insulation is NOT necessary before adding new.
Best Time of Year to Buy Insulation
In this case, the spring is the best time, because you will also start to see savings in the summer months. The same is true for warmer climates, just different times of year because you'll want the job finished before the heat sets in.
Adding new insulation depends on various factors. If your old insulation is damp or water-damaged, it must be removed and replaced. If the current insulation has always been dry, you can add fresh insulation on top of it.
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. That being said, though, blown fiberglass insulation isn't meant to cover huge areas like rolled fiberglass insulation.
Double the Defense, Superior Performance:
Once the first layer is secured, a second layer of unfaced fiberglass insulation is installed. This layer is positioned perpendicular to the roof purlins, running from the peak to the eave, and directly over the top of the first layer.
If your old insulation is made of mineral wool or natural fibers, you can take it a recycling center. Fiberglass insulation can also be recycled, but it requires more specialized facilities, so you can call the center beforehand and inquire about the kind of insulation materials they readily accept.
According to experts from Realtor.com, old homes, especially ones built on or before the 1960s, weren't built with insulation in mind.
The short answer is yes, upgrading insulation can increase the resale value of a home.